Efficient waste heat recovery system based on secondary lead smelting and cascade use method thereof

Abstract

The invention relates to the technical field of waste heat recovery, and particularly discloses an efficient waste heat recovery system based on secondary lead smelting and a cascade using method thereof.The efficient waste heat recovery system comprises a smelting furnace, an air preheater, a cyclone dust collector, a box type dust collector, a waste heat boiler and a raw material drying machine which are sequentially connected; a vertical cylinder with the lower end extending out is concentrically fixed to the top of the heat preservation outer shell, a heat exchange rotor is rotationally arranged at the upper end of the vertical cylinder, the interior of the heat exchange rotor is evenly divided into a plurality of sealed fan-shaped spaces, the fan-shaped spaces are filled with phase change heat storage materials, and a plurality of sets of vertical tubes are arranged in each fan-shaped space. A plurality of groups of radial through heat exchange tubes are arranged in each fan-shaped space; according to the waste heat efficient recovery system and the waste heat cascade using method, on the premise that high-temperature flue gas waste heat is efficiently utilized, corrosion of high-temperature strong acid gas to the heat exchange pipes and the heat exchange media can be avoided, and the service life of the air preheater is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of waste heat recovery, and specifically discloses a high-efficiency waste heat recovery system based on secondary lead smelting and its cascade utilization method. Background Art

[0002] Lead metal plays a crucial role in many fields such as battery manufacturing, chemical industry, and electronics. However, primary lead ore resources are non-renewable resources. With the increasingly strict environmental protection requirements, the recycling of secondary lead has positive significance in aspects such as resource utilization efficiency, energy consumption, and environmental pollution control. The existing recycling of secondary lead mainly uses pyrometallurgy, that is, crushed waste lead materials (such as waste lead-acid batteries, lead alloys, etc.) are added into a smelting furnace together with coke, flux, etc. By blowing air to make the coke burn to generate high temperature, a series of physical and chemical reactions occur to the waste lead materials at high temperature to achieve recycling. However, during the lead metal smelting process, flue gas at about 300 - 400 °C will be generated, and the effective utilization of the heat in the flue gas also has positive significance in terms of energy conservation and environmental protection in the secondary lead smelting and recycling process.

[0003] At present, the waste heat utilization in the secondary lead smelting process mainly uses heat energy recovery equipment such as air preheaters and waste heat boilers to achieve waste heat recovery. Especially during the process of recovering the waste heat of the secondary lead smelting flue gas by an air preheater, since the flue gas not only has a large dust content but also has a strong acidity, when using a tubular air preheater for preheating recovery, the surface of its internal heat exchange tubes is extremely easy to adhere to dust, and it is impossible to clean it online in time, resulting in a significant decline in the heat exchange effect; during the process of using a traditional rotary air preheater for preheating recovery, after some acidic dust adheres to the surface of the heat absorption fins and then exchanges heat with the incoming air, the moisture in the air is easy to dissolve the acidic dust, resulting in serious corrosion of the heat absorption fins and reducing their service life. Therefore, aiming at the technical problems and deficiencies existing in the process of preheating and recovering the secondary lead smelting flue gas by the existing air preheater, this application proposes a high-efficiency waste heat recovery system based on secondary lead smelting and its waste heat cascade utilization method. Summary of the Invention

[0004] The present invention aims to provide a high-efficiency waste heat recovery system based on secondary lead smelting and its cascade utilization method to solve the problems of waste heat utilization in the existing secondary lead smelting process, especially the problems of the decline in heat exchange effect caused by the inability to clean dust online when directly using an air preheater to heat exchange the high-temperature flue gas, and the easy corrosion of fins and pipelines caused by the combination of strong acid flue gas and moisture in the air.

[0005] The present invention is achieved by the following technical solutions: A high-efficiency waste heat recovery system based on secondary lead smelting, comprising a smelting furnace, an air preheater, a cyclone dust collector, a box-type dust collector, a waste heat boiler and a raw material dryer connected in sequence, and the high-temperature air outlet of the air preheater is connected to the bottom of the smelting furnace through a pipeline; The air preheater includes a heat-insulating outer shell, a vertical cylinder with its lower end extending out is fixedly arranged concentrically at the top of the heat-insulating outer shell, a heat exchange rotor cooperating with the heat-insulating outer shell is rotatably arranged at the upper end of the vertical cylinder, and a rotary drive assembly is connected between the outer end of the heat exchange rotor extending out of the heat-insulating outer shell and the end of the annular gap at the lower end of the vertical cylinder; The interior of the heat exchange rotor is evenly divided into a plurality of sealed fan-shaped spaces, and phase change heat storage materials are filled in the fan-shaped spaces. A plurality of groups of vertical tubes arranged circumferentially and penetrating up and down are arranged in each fan-shaped space, and a plurality of groups of heat exchange tubes penetrating radially are arranged in each fan-shaped space, and the plurality of groups of heat exchange tubes are arranged along the center line of the included angle between two adjacent groups of vertical tubes; A flue gas outlet and a flue gas inlet are respectively arranged at the upper and lower ends of the heat-insulating outer shell, and the part where the flue gas inlet and the flue gas discharge port are aligned up and down covers the annular track area of the rotation movement of each group of vertical tubes. A conduction port communicating with the inner ends of all the heat exchange tubes in the fan-shaped space is opened on the vertical cylinder downstream of the flue gas inlet, and a wind collecting hood is arranged on the heat-insulating outer shell on the radial outer side of the conduction port. The outer end of the wind collecting hood is connected with a hot air conduit, and a blower is connected to the lower end of the vertical cylinder.

[0006] The high-efficiency waste heat recovery system disclosed by the invention can utilize the waste heat of the high-temperature flue gas in the secondary lead smelting process three times successively. The first waste heat utilization generates high-temperature air to supply oxygen for the smelting furnace. The high-temperature steam and hot water generated by the second waste heat utilization can be used for power generation and meet the hot water supply. The third waste heat utilization can dry the crushed and mixed lead waste materials to reduce the water vapor in the flue gas during the smelting process. Especially in the process of the first waste heat utilization, the supply air of the smelting furnace is directly heated to more than 150 °C through a specially designed air preheater, so that it can not only provide sufficient oxygen for the smelting process, but also the high-temperature air can prevent the temperature of the molten liquid in the furnace from dropping, effectively reducing the fuel consumption of the smelting furnace when smelting waste lead materials.

[0007] Meanwhile, the air preheater in the present invention takes the traditional rotary air preheater as the main framework, but uses vertical tubes, phase change heat storage materials, and heat exchange tubes as the heat transfer and heat storage media. During the up-and-down axial flow of the high-temperature flue gas, heat is transferred to the phase change heat storage materials through the absorption of heat by the vertical tubes, causing them to heat up and store heat. Then, the heat exchange tubes enable the air to flow radially through the phase change heat storage materials, thereby absorbing the released heat and heating it up. Compared with the traditional rotary air preheater, the flow areas of the high-temperature flue gas and the air are completely separated, which can prevent the attached acidic dust from generating strong acid substances when encountering moisture in the air and corroding the heat transfer and conduction media, effectively ensuring its service life.

[0008] As a further setting of the above solution, an automatic air blowing cleaning mechanism for sequentially cleaning each group of vertical tubes is provided on the heat preservation outer shell located downstream of the air collecting hood and upstream of the flue gas inlet.

[0009] As a further setting of the above solution, the automatic air blowing cleaning mechanism includes a compressed air source and a strip-shaped box arranged on the upper surface of the heat preservation outer shell. A compressed air pipe extending into the strip-shaped box is connected to the compressed air source. The end of the compressed air pipe is connected to an automatic on-off device, and the other end of the automatic on-off device is connected to a jet pipe. Nozzles that are vertically aligned with the circular trajectories of each vertical tube in a group of vertical tubes are arranged on the lower surface of the jet pipe.

[0010] As a further setting of the above solution, the automatic on-off device includes a valve body with both ends respectively connected to the jet pipe and the compressed air pipe. A vertical channel is arranged in the middle of the valve body. A plug column is connected in the vertical channel through a spring, and air flow through holes aligned with the jet pipe and the compressed air pipe are provided on the plug column. The plug column is connected to a magnet attracting block extending out through a lifting rod. Magnets corresponding to each group of vertical tubes are arranged at the upper ends of the fan-shaped spaces. The magnets are arranged on the extension lines of the connections of each group of vertical tubes and are vertically aligned with the magnet attracting block during rotation.

[0011] The above is a further optimized design of the present invention for on-line cleaning of the air preheater. In the gap area between flue gas heat release and air heat absorption, high-pressure air flow discharged from the compressed air source is used to on-line blow and clean the dust and impurities attached to each group of vertical tubes. During the specific operation process, when a group of vertical tubes rotates and moves to align vertically with the spray pipe, the magnetic attraction block in the automatic on-off device will also align vertically with the corresponding magnet at this time. Then, under the action of magnetic attraction, the plug column is stretched downward in the vertical channel, so that the air flow channel on the plug column is connected to the spray pipe and the compressed air pipe. Then, the compressed gas can pass smoothly and finally be discharged from the nozzle. When a group of vertical tubes moves away from directly below the spray pipe, the plug column will reset again under the action of the spring, so as to cut off the compressed air discharged from the compressed air pipe and avoid waste of compressed air discharge. The design of the entire automatic air blowing and cleaning mechanism not only realizes the sequential cleaning of each group of vertical tubes, but also does not require setting solenoid valves, sensors and controllers to control the start and stop of the automatic air blowing and cleaning mechanism, making the start and stop of the automatic air blowing and cleaning mechanism synchronized with the rotation process of the heat exchange rotor.

[0012] As a further setting of the above solution, the heat exchange rotor includes an inner ring plate and an outer ring plate that are concentrically arranged inside and outside. The inner ring plate is rotatably arranged in contact with the outer surface of the vertical cylinder, and the outer ring plate is arranged in contact with the inner wall of the heat preservation housing. A plurality of radially arranged partitions are evenly arranged between the inner ring plate and the outer ring plate, and the partitions equally divide the space between the inner ring plate and the outer ring plate into a plurality of fan-shaped spaces. Sealing plates are fixedly arranged at both the upper and lower ends of each fan-shaped space.

[0013] As a further setting of the above solution, the inner ring plate extends downward out of the heat preservation housing, and a gear ring is arranged at the lower end of the inner ring plate. The rotation drive assembly includes a power motor, and a power gear meshing with the gear ring is connected to the power motor.

[0014] As a further setting of the above solution, a circular hole is opened at the center of the lower end of the heat preservation housing, and a sealing bearing connected to the inner ring plate is arranged in the circular hole.

[0015] As a further setting of the above solution, the vertical tubes in each group of vertical tubes are arranged at intervals in the radial direction, and the heat exchange tubes in each group of heat exchange tubes are arranged at intervals up and down.

[0016] As a further setting of the above solution, a fin ring is arranged on the outer surface of the vertical tube, and the cross-sectional dimension or pipe diameter of the heat exchange tube extending from the radially inner end to the outer end gradually increases.

[0017] The present invention also discloses a method for cascaded use of waste heat based on the above waste heat efficient recovery system, which is characterized by including the following steps: 1) The high-temperature flue gas discharged from the smelting furnace is directly heat-exchanged by the air preheater to generate high-temperature air and primary heat-exchanged flue gas, and the generated high-temperature air is introduced into the bottom of the smelting furnace to supply oxygen during the smelting process; 2) The primary heat-exchanged flue gas is subjected to dust removal treatment, and after dust removal, it is introduced into the waste heat boiler for heat exchange. The high-temperature steam and high-temperature hot water generated by the waste heat boiler are used for power generation and water supply respectively; 3) The secondary heat-exchanged flue gas discharged from the waste heat boiler is introduced into the raw material dryer to dry the waste lead material. The tertiary heat-exchanged flue gas generated after drying is sent to the flue gas treatment equipment for treatment, and the waste lead material treated by the raw material dryer is sent to the smelting furnace for smelting and recovery.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The waste heat high-efficiency recovery system and waste heat cascade utilization method for secondary lead smelting disclosed by the present invention not only realize the three-stage utilization of high-temperature flue gas during the secondary lead smelting process, effectively avoid heat loss, but also can effectively reduce the fuel consumption during the secondary lead smelting process, and have better energy conservation and emission reduction effects.

[0019] The air preheater in the present invention directly utilizes the waste heat of the high-temperature flue gas discharged from the smelting furnace, which can avoid the high-temperature heat loss during the process of first dust removal and then waste heat utilization. And through the special structural design of the whole air preheater, on the premise of realizing the high-efficiency utilization of the waste heat of the high-temperature flue gas, it can avoid the corrosion of the heat exchange tubes and heat exchange medium caused by high-temperature strong acidic gases, and ensure the service life of the air preheater.

[0020] The air preheater in the present invention is further provided with an automatic air-blowing cleaning mechanism, which not only realizes the on-line air-blowing cleaning of the vertical tubes, but also the air-blowing cleaning process is arranged after the air heat absorption process, which can effectively reduce the heat loss caused by the air-blowing cleaning process. The cleaned vertical tubes can maintain high-efficiency heat absorption performance of high-temperature flue gas, and overall effectively improve the waste heat utilization efficiency of the whole air preheater. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. 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 be obtained based on these drawings.

[0022] Figure 1 It is a schematic connection structure diagram of the waste heat high-efficiency recovery system of the present invention; Figure 2 It is a three-dimensional structure diagram of the first angle of the air preheater in the present invention; Figure 3 This is a three-dimensional structural schematic diagram of the air preheater in the present invention from a second angle; Figure 4 This is a three-dimensional structural schematic diagram of the heat exchange rotor in the present invention from a first angle; Figure 5 This is a three-dimensional structural schematic diagram of the heat exchange rotor in the present invention from a second angle; Figure 6 This is a three-dimensional structural schematic diagram when the vertical tubes and the heat exchange tubes are arranged relatively in the present invention; Figure 7 This is a three-dimensional structural schematic diagram inside the heat preservation outer shell and the vertical cylinder in the present invention; Figure 8 This is a three-dimensional structural schematic diagram of the automatic air blowing cleaning mechanism in the present invention; Figure 9 This is an internal planar structural schematic diagram of the automatic on-off device in the present invention; Figure 10 This is a planar structural schematic diagram of each interval section of the air preheater in the present invention. Detailed implementation manners

[0023] In order to enable those skilled in the art to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0024] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following will refer to the attached Figures 1 to 10 drawings and describe this application in detail in conjunction with the embodiments. Embodiment 1

[0025] Embodiment 1 discloses a waste heat efficient recovery system based on secondary lead smelting. Referring to the attached Figure 1 drawings, the main body of this system includes a smelting furnace 100, an air preheater 200, a cyclone dust collector 300, a box-type dust collector 400, a waste heat boiler 500, and a raw material dryer 600. Among them, the smelting furnace 100 is connected to the flue gas inlet of the air preheater 200 through a heat preservation pipeline, and the flue gas outlet of the air preheater 200 is sequentially connected to the cyclone dust collector 300 and the box-type dust collector 400 through a heat preservation pipeline. At the same time, the high-temperature air outlet of the air preheater 200 is connected to the bottom of the smelting furnace 100 through a pipeline. The air outlet of the box-type dust collector 400 is connected to the waste heat boiler 500 through a heat preservation pipeline, and the air outlet of the waste heat boiler 500 is connected to the raw material dryer 600 through a pipeline.

[0026] During the operation of the entire recycling system, the high-temperature flue gas in the smelting furnace 100 is introduced into the air preheater 200 to heat the air. The heated high-temperature air is directly introduced into the bottom of the smelting furnace 100 to supply oxygen and provide appropriate heat. The secondary flue gas after heat exchange in the air preheater 200 enters the cyclone dust collector 300 for cyclone dust removal to remove most of the large particle impurities, and then enters the box-type dust collector 400 to be filtered by sintered filter elements or dust removal cloth bags. The flue gas after secondary dust removal then enters the waste heat boiler 500 for heat exchange. The high-temperature steam generated by the waste heat boiler 500 is directly introduced into the steam turbine for power generation, and the generated high-temperature hot water is introduced into the external pipe network to meet the hot water supply demand. The tertiary flue gas after heat exchange in the waste heat boiler 500 is then introduced into the raw material dryer 600 to dry the waste lead material. The dried waste lead material is directly sent into the smelting furnace 100 for smelting and extraction. Finally, the tail gas discharged from the raw material dryer 600 is sent into the corresponding flue gas treatment equipment for treatment and discharged after meeting the emission requirements.

[0027] In the air preheater 200 in this Embodiment 1, it is directly connected to the smelting furnace 100, so that the high-temperature flue gas generated by the smelting furnace 100 can be effectively utilized to generate high-temperature air in the first time, avoiding heat loss caused by the process of dust removal first and then heat exchange, ensuring that the temperature of the air introduced into the smelting furnace 100 after heat exchange is as high as 150 °C. Then, the air at this temperature is introduced into the smelting furnace 100, which can not only provide sufficient oxygen for the smelting process, but also the high-temperature air can prevent the temperature of the molten liquid in the furnace from dropping, effectively reducing the fuel consumption of the smelting furnace 100 when smelting the waste lead material.

[0028] Reference appendix Figures 2 - 9 Referring to the appendix, the air preheater 200 in this Embodiment 1 includes a cylindrical heat-insulating outer shell 1. A circular hole is opened at the center of the lower end of the heat-insulating outer shell 1, and a sealed bearing 101 is arranged in the circular hole. Then, a plurality of support legs 2 are also arranged on the lower surface of the heat-insulating outer shell 1, so that the entire heat-insulating outer shell 1 can be stable on the ground. A vertical cylinder 3 is arranged at the center of the top of the heat-insulating outer shell 1 and penetrates through the sealed bearing 101 vertically downward. Then, a heat exchange rotor 4 adapted to the inner cavity of the heat-insulating outer shell 1 is rotatably arranged in a fitting manner on the outer surface of the cylinder 3.

[0029] The specific heat exchange rotor 4 includes an inner ring plate 401 and an outer ring plate 402 which are concentrically arranged inside and outside. The inner ring plate 401 is rotatably arranged in contact with the outer surface of the vertical cylinder 3, and its lower end extends out of the annular gap between the sealing bearing 101 and the vertical cylinder 3. Then, a gear ring 403 is arranged at the lower end of the inner ring plate 401. One end of the gear ring 403 meshes with a power gear 5, and the power gear 5 is connected to a power motor 6. The outer ring plate 402 is in contact with the inner wall of the heat preservation outer shell 1. Then, a plurality of radially arranged partition plates 404 are evenly arranged between the inner ring plate 401 and the outer ring plate 402. Through the partition plates 404, a plurality of fan-shaped spaces are formed in the heat exchange rotor 4, and sealing plates 405 are fixedly arranged at both the upper and lower ends of each fan-shaped area. Then, a phase change heat storage material is filled in the fan-shaped space between the upper and lower sealing plates 405.

[0030] A plurality of groups of vertically penetrating vertical tubes 406 are arranged between the upper and lower sealing plates 405. The plurality of groups of vertical tubes 406 are circumferentially and evenly arranged in the fan-shaped space, and the vertical tubes 406 in each group of vertical tubes 406 are arranged at intervals in the radial direction. In addition, in order to enhance the heat conduction capacity of the vertical tubes 406 to the high-temperature flue gas, corresponding fin rings 4061 are additionally arranged on the outer surface of the vertical tubes 406, so that the heat absorbed by the vertical tubes 406 can be quickly transferred to the phase change heat storage material. A plurality of groups of radially penetrating heat exchange tubes 407 are arranged in the fan-shaped space between the upper and lower sealing plates 405. The plurality of groups of heat exchange tubes 407 are arranged along the center line of the included angle between two adjacent groups of vertical tubes 406. And the heat exchange tubes 407 in each group of heat exchange tubes 407 are arranged at intervals up and down. At the same time, during the process of the heat exchange tubes 407 extending from the radially inner end to the outer end, their cross-sectional dimensions or pipe diameters are gradually increased.

[0031] A flue gas inlet 102 is arranged at one end of the lower surface of the heat preservation outer shell 1, and a flue gas outlet 103 is arranged on the upper surface of the heat preservation outer shell 1 directly above the flue gas inlet 102. And the area where the flue gas inlet 102 and the flue gas outlet 103 are vertically aligned can completely cover the annular track area where each group of vertical tubes 406 rotates and moves. A blower 7 is arranged directly below the heat preservation outer shell 1, and an air inlet pipe 8 which is hermetically extended into the vertical cylinder 3 is connected to the blower 7. A conduction port 301 which is communicated with the inner ends of all the heat exchange tubes 407 in a fan-shaped space is arranged on one side surface of the upper end of the vertical cylinder 3. Then, a wind collecting cover 9 is arranged on the outer circular surface of the heat preservation outer shell 1 radially outside the conduction port 301, and the wind collecting cover 9 is radially aligned with the conduction port 301. Finally, a hot air duct 10 is connected to the outer end of the wind collecting cover 9, and the hot air duct 10 can be connected to the bottom of the smelting furnace 100 so as to continuously provide the smelting furnace 100 with the heat-exchanged high-temperature air.

[0032] During the specific operation of the air preheater 200 disclosed in this Embodiment 1, under the meshing drive of the power motor 6, the power gear 5 and the gear ring 403, the heat exchange rotor 4 rotates uniformly in the annular space between the heat preservation housing 1 and the vertical cylinder 3. At this time, the high-temperature flue gas discharged from the top of the smelting furnace 100 directly passes through the flue gas inlet 102. The introduced high-temperature flue gas will flow upward and pass through the vertical tubes 406 that are aligned with it at this time. When the high-temperature flue gas flows in the vertical tubes 406, its own heat will be absorbed by the vertical tubes 406 and transferred to the phase change heat storage material in the fan-shaped space, causing the phase change heat storage material to increase in temperature and store heat, while the cooled high-temperature flue gas is discharged from the flue gas outlet 103.

[0033] Subsequently, when this fan-shaped space rotates and moves between the conduction port 301 and the air collecting hood 9, since the blower 7 continuously introduces air into the vertical cylinder 3, the air pressure in the vertical cylinder 3 will be greater than the external air pressure. When the radially inner end of the heat exchange tube 407 in this fan-shaped space is aligned and connected with the conduction port 301, the air in the vertical cylinder 3 will flow radially outward along the heat exchange tube 407, and the air will absorb the heat emitted by the phase change heat storage material when flowing in the heat exchange tube 407. At the same time, due to the design of the heat exchange tube 407 with a narrow inner part and a wide outer part, the flow velocity of the air will become slower and slower, improving the actual heat exchange between the air and the phase change heat storage material in the heat exchange tube 407, so that the temperature of the air finally entering the air collecting hood 9 can exceed 150°C, and finally the heated high-temperature air is introduced into the smelting furnace 100. Embodiment 2

[0034] Embodiment 2 discloses a waste heat efficient recovery system based on secondary lead smelting that further optimizes the design of the air preheater 200 based on the technical solution in Embodiment 1. The same parts as in Embodiment 1 will not be described again.

[0035] This Embodiment 2 also provides an automatic air blowing cleaning mechanism 11 on the air preheater 200. The automatic air blowing cleaning mechanism 11 is arranged downstream of the air collecting hood 9 and upstream of the flue gas inlet 102. It includes a compressed air source 111. Specifically, the compressed air source 111 can be a compressed air bag or an air compressor, and a compressed air pipe 112 is connected to the compressed air source 111. At the same time, a strip-shaped box 104 protruding upward is arranged on the upper surface of the heat preservation housing 1, and the compressed air pipe 112 is extended into the strip-shaped box 104. Then, a jet pipe 114 is connected to the end of the compressed air pipe 112 through an automatic on-off device 113. The jet pipe 114 is arranged radially, and nozzles 115 that are vertically aligned with the annular track of each vertical tube 406 are arranged on the lower surface of the jet pipe 114.

[0036] The automatic on-off device 113 in this Embodiment 2 includes a valve body 1131 with two ends respectively connected to the air injection pipe 114 and the compressed air pipe 112. A vertical channel 1132 is provided in the middle of the valve body 1131. A plug column 1134 is connected in the vertical channel 1132 through a spring 1133, and an air flow hole 1135 aligned with the air injection pipe 114 and the compressed air pipe 112 is opened at the upper end of the plug column 1134. Then, a protruding lifting rod 1136 is connected to the lower end of the plug column 1134, and a magnetic attraction block 1137 is provided at the lower end of the lifting rod 1136. In addition, a magnet 1138 corresponding to each group of vertical tubes 406 is fixedly installed on the upper surface of each upper sealing plate 405. The magnet 1138 is arranged on the radial extension line of the connection line of a corresponding group of vertical tubes 406 and can be vertically aligned with the magnetic attraction block 1137 during rotation.

[0037] Finally, a dust suction pipe 12 is connected to the lower surface of the heat preservation outer shell 1 directly below the strip box 104. The end of the dust suction pipe 12 is connected to a filter box 13, and a negative pressure fan 14 is connected to the other end of the filter box 13.

[0038] The design of the automatic air blowing and cleaning mechanism 11 in this Embodiment 2 can perform on-line cleaning of the vertical tubes 406. During specific operation, the fan-shaped space after air heat exchange will rotate and move towards one side of the automatic air blowing and cleaning mechanism 11. At this time, after the phase change heat storage material in the fan-shaped space undergoes air heat exchange, most of the heat has been absorbed and carried away by the air, and even if the remaining small amount of waste heat is treated by air blowing, it will not cause excessive heat waste. When a group of vertical tubes 406 to be cleaned move to be vertically aligned with the air injection pipe 114, at this time, not only each nozzle 115 is located directly above the corresponding vertical tube 406, but also the magnet 1138 on the upper surface of the sealing plate 405 is vertically aligned with the magnetic attraction block 1137 in the automatic on-off device 113. Then, under the action of magnetic attraction, the magnetic attraction block 1137, the lifting rod 1136 and the plug column 1134 move downward against the acting force of the spring 1133, so that the air flow hole 1135 on the plug column 1134 is aligned and communicated with the left and right ends of the valve body 1131. The compressed air in the compressed air source 111 can enter the air injection pipe 114 and be discharged from the nozzle 115, thereby blowing off the dust and impurities attached to the inner wall of the vertical tube 406. The blown-off dust and impurities will be sucked by the negative pressure fan 14, introduced into the filter box 13 through the dust suction pipe 12, and discharged by the negative pressure fan 14 after filtration.

[0039] After cleaning is completed, a group of vertical tubes 406 rotate to be staggered from the air injection pipe 114. At this time, the magnetic suction force weakens or even disappears. Then, under the action of the spring 1133, the automatic on-off device 113 automatically cuts off the compressed gas in the pipeline, avoiding the loss of compressed air flow. After the next group of vertical tubes 406 move to align with the air injection pipe 114, the above actions are repeated for air blowing and cleaning, so as to clean all the vertical tubes 406 after heat exchange one by one. Before they move to pass through the high-temperature flue gas, there is no dust and impurities on the inner wall, effectively ensuring the heat absorption effect of the vertical tubes 406 on the high-temperature flue gas heat. Embodiment 3

[0040] Embodiment 3 discloses a method for cascaded use of waste heat using the waste heat high-efficiency recovery system disclosed in the above Embodiment 1 or Embodiment 2, which includes the following steps: S1: Use the air preheater 200 to directly exchange heat with the high-temperature flue gas discharged from the smelting furnace 100 to generate high-temperature air and primary heat-exchanged flue gas, and introduce the generated high-temperature air into the bottom of the smelting furnace 100 to supply oxygen during the smelting process; S2: The primary heat-exchanged flue gas is successively dust-removed by using a cyclone dust collector 300 and a box-type dust collector 400, and after dust removal, it is introduced into the waste heat boiler for heat exchange. The high-temperature steam generated by the waste heat boiler is introduced into the steam turbine for power generation, and the high-temperature hot water generated by the waste heat boiler is introduced into the external pipe network to meet the hot water supply demand; S3: The secondary heat-exchanged flue gas discharged from the waste heat boiler is introduced into the raw material dryer 600 to dry the waste lead material. The tertiary heat-exchanged flue gas generated after drying is sent to the flue gas treatment equipment for treatment, and after reaching the standard, it is discharged. The waste lead material dried by the raw material dryer 600 is then sent to the smelting furnace 100 for smelting and recovery.

[0041] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A waste heat efficient recovery system based on secondary lead smelting, characterized in that: It includes a smelting furnace, an air preheater, a cyclone dust collector, a box-type dust collector, a waste heat boiler and a raw material dryer which are connected in sequence, and the high-temperature air outlet of the air preheater is connected to the bottom of the smelting furnace through a pipeline; The air preheater comprises an insulating outer shell, a vertical cylinder is concentrically fixed on the top of the insulating outer shell and the lower end of the vertical cylinder is extended, a heat exchange rotor matching the insulating outer shell is rotatably arranged on the upper end of the vertical cylinder, and the end of the heat exchange rotor extending out of the insulating outer shell and the annular gap at the lower end of the vertical cylinder is connected to a rotary drive assembly; The interior of the heat exchange rotor is evenly divided into a plurality of sealed fan-shaped spaces, and the fan-shaped spaces are filled with phase-change heat storage materials, each of the fan-shaped spaces is provided with a plurality of groups of vertical tubes evenly arranged in the circumferential direction and penetrating up and down, each of the fan-shaped spaces is provided with a plurality of groups of radially penetrating heat exchange tubes, and the plurality of groups of heat exchange tubes are arranged along the center line of the angle between two adjacent groups of vertical tubes; The upper and lower ends of the thermal insulation outer shell are respectively provided with a smoke outlet and a smoke inlet which are aligned vertically, and the vertically aligned parts of the smoke inlet and the smoke outlet cover the annular trajectory area of ​​the rotation and movement of each group of vertical array tubes, and a conducting port connected to the inner ends of all heat exchange tubes in the fan-shaped space is opened on the vertical cylinder located downstream of the smoke inlet, and an air collecting hood is arranged on the thermal insulation outer shell radially outside the conducting port, and the outer end of the air collecting hood is connected to a hot air duct, and the lower end of the vertical cylinder is connected to a blower.

2. The waste heat efficient recovery system based on secondary lead smelting according to claim 1 is characterized in that: An automatic air blowing cleaning mechanism for sequentially cleaning each group of vertical tubes is arranged on the heat-insulating outer shell located downstream of the wind collecting hood and upstream of the smoke inlet.

3. The waste heat efficient recovery system based on secondary lead smelting according to claim 2 is characterized in that: The automatic air blowing cleaning mechanism includes a compressed air source and a strip box arranged on the upper surface of the heat-insulating outer shell, the compressed air source is connected to a compressed air pipe extending into the strip box, the end of the compressed air pipe is connected to an automatic on-off device, the other end of the automatic on-off device is connected to an air jet pipe, and the lower surface of the air jet pipe is provided with a nozzle aligned up and down with the annular trajectory of each vertical column of tubes in a group of vertical columns of tubes.

4. The waste heat efficient recovery system based on secondary lead smelting according to claim 3 is characterized in that: The automatic on-off device includes a valve body whose two ends are respectively connected to the air jet pipe and the compressed air pipe, a vertical channel is arranged in the middle of the valve body, a blocking column is connected to the vertical channel through a spring, and an air flow hole aligned with the air jet pipe and the compressed air pipe is opened on the blocking column, the blocking column is connected to a protruding magnetic block through a lifting rod, and a magnet corresponding to each group of vertical tubes is arranged at the upper end of the fan-shaped space, the magnet is arranged on the extension line of the connection line of each group of vertical tubes and is aligned with the magnetic block up and down during rotation.

5. The waste heat efficient recovery system based on secondary lead smelting according to claim 1 is characterized in that: The heat exchange rotor includes an inner ring plate and an outer ring plate which are concentrically arranged inside and outside. The inner ring plate is arranged to rotate in contact with the outer surface of the vertical cylinder, and the outer ring plate is arranged to fit the inner wall of the thermal insulation outer shell. A plurality of radially arranged partitions are evenly arranged between the inner ring plate and the outer ring plate, and the partitions divide the space between the inner ring plate and the outer ring plate into a plurality of fan-shaped spaces. Sealing plates are fixedly arranged at the upper and lower ends of each fan-shaped space.

6. The waste heat efficient recovery system based on secondary lead smelting according to claim 5 is characterized in that: The inner ring plate extends downward from the heat-insulating outer shell, and a gear ring is arranged at the lower end of the inner ring plate. The rotary drive assembly includes a power motor, and a power gear meshing with the gear ring is connected to the power motor.

7. The waste heat efficient recovery system based on secondary lead smelting according to claim 6 is characterized in that: A circular hole is provided at the center of the lower end of the heat-insulating outer shell, and a sealing bearing connected to the inner ring plate is arranged in the circular hole.

8. The waste heat efficient recovery system based on secondary lead smelting according to claim 1 is characterized in that: The vertical tubes in each group of vertical tubes are arranged at intervals in the radial direction, and the heat exchange tubes in each group of heat exchange tubes are arranged at intervals up and down.

9. The waste heat efficient recovery system based on secondary lead smelting according to claim 8 is characterized in that: The outer surface of the vertical tube array is provided with a fin ring, and the cross-sectional size or tube diameter of the heat exchange tube extending from the radial inner end to the outer end is gradually increased.

10. A method for using waste heat in stages based on the waste heat efficient recovery system according to any one of claims 1 to 9, characterized in that: The steps include: 1) Use the air preheater to directly heat the high-temperature flue gas discharged from the smelting furnace to generate high-temperature air and primary heat exchange flue gas, and pass the generated high-temperature air into the bottom of the smelting furnace to provide nourishment for the smelting process; 2) The flue gas from the primary heat exchange is subjected to dust removal treatment and then introduced into the waste heat boiler for heat exchange. The high-temperature steam and high-temperature hot water generated by the waste heat boiler are used for power generation and water supply respectively; 3) The secondary heat exchange flue gas discharged from the waste heat boiler is passed into the raw material dryer to dry the scrap lead. The tertiary heat exchange flue gas generated after drying is sent to the flue gas treatment equipment for treatment. The scrap lead treated by the raw material dryer is sent to the smelting furnace for smelting and recovery.

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