Flue gas waste heat utilization system

Abstract

The invention provides a flue gas waste heat utilization system, and relates to the technical field of aluminum oxide production. A heat exchange water pipe; the flue gas pipeline and the heat exchange water pipe realize heat exchange through the first heat exchange equipment, so that water in the heat exchange water pipe is heated to a second specified temperature; the second heat exchange equipment is used for heating the filtrate in the filtrate tank; the filtrate tank is provided with a filtrate inlet and a filtrate outlet; the filtrate inlet is sequentially connected with red mud filter pressing equipment for producing aluminum oxide, red mud washing equipment and low-temperature dissolution equipment; and the red mud filter pressing equipment is connected with the flue gas pipeline through a shunting pipeline. According to the invention, the filtrate in the filtrate tank is heated by using flue gas and then is sent back to the low-temperature dissolution equipment. Flue gas is guided into the red mud filter pressing equipment through the flow dividing pipeline, so that filter cakes obtained after filter pressing are heated, and the dehydration rate of the filter cakes is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of alumina production, and in particular to a flue gas waste heat utilization system. Background Art

[0002] Refer to Figure 1 , the production of alumina includes processes such as raw pulp grinding, low-temperature digestion, red mud separation, roasting, etc. Among them, the roasting process generates flue gas at 600-900°C; the red mud obtained after red mud separation needs to go through processes such as red mud washing and red mud pressure filtration. In the red mud pressure filtration process, the filtrate obtained can be sent back to the low-temperature digestion process after being heated to 80-90°C, playing a role in alkali recovery.

[0003] If the flue gas generated in the roasting process is directly filtered through a bag filter, the waste heat of the flue gas will be wasted, which does not conform to the company's concept of energy conservation and emission reduction.

[0004] In order to make full use of the waste heat of the flue gas generated in processes such as the roasting process, the present application uses the waste heat of the flue gas to heat the above-mentioned filtrate, which conforms to the company's concept of energy conservation and emission reduction. In addition, using the waste heat of the flue gas to heat the filter cake after pressure filtration improves the dehydration rate of the filter cake. Summary of the Invention

[0005] In view of the above situation, the present invention provides a flue gas waste heat utilization system, which can use the waste heat of the flue gas to heat the filtrate, conforming to the company's concept of energy conservation and emission reduction. In addition, using the waste heat of the flue gas to heat the filter cake after pressure filtration improves the dehydration rate of the filter cake.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a flue gas waste heat utilization system, including:

[0008] A flue gas pipeline for transporting flue gas with a first specified temperature;

[0009] A heat exchange water pipe for transporting industrial water or raw water;

[0010] A first heat exchange device, through which the flue gas pipeline and the heat exchange water pipe perform heat exchange to heat the industrial water or raw water in the heat exchange water pipe to a second specified temperature;

[0011] A second heat exchange device for heating the filtrate in the filtrate tank to 80-90°C;

[0012] Wherein, the filtrate tank has a filtrate inlet and a filtrate outlet; the filtrate inlet is successively connected with a red mud pressure filtration device, a red mud washing device and a low-temperature digestion device for producing alumina; the filtrate outlet is connected to the inlet of the low-temperature digestion device through a filtration device;

[0013] The red mud pressure filtration equipment is connected to the flue gas pipeline through a shunt pipeline. The shunt pipeline is used to introduce the flue gas into the red mud pressure filtration equipment to heat the filter cake after pressure filtration and improve the dehydration rate of the filter cake.

[0014] In some embodiments of the present invention, the red mud pressure filtration equipment includes a fixing plate and pressure filtration plates;

[0015] A plurality of pressure filtration plates are arranged horizontally and movably on the right side of the fixing plate; the left side of the pressure filtration plate has a groove, and an extrusion plate is slidably connected horizontally in the groove. The left side of the extrusion plate and the side wall of the groove form a pressure filtration cavity; the pressure filtration plate located on the leftmost side can be in contact with the right side of the fixing plate to block the pressure filtration cavity of the pressure filtration plate, and two adjacent pressure filtration plates can be in contact with each other to block the corresponding pressure filtration cavity;

[0016] The right side of the pressure filtration plate has a mud inlet communicating with the pressure filtration cavity, the lower part has a liquid discharge port communicating with the pressure filtration cavity, the upper part has a smoke exhaust port communicating with the pressure filtration cavity, the liquid discharge port is connected with a mud inlet head, and the mud inlet head is connected with the shunt pipeline.

[0017] In some embodiments of the present invention, the red mud pressure filtration equipment further includes:

[0018] A connecting pipe is connected in the mud inlet, and the left end of the connecting pipe extends into the groove;

[0019] A sleeve is horizontally movably sleeved on the outer wall of the connecting pipe; the outer wall of the sleeve is slidably connected with the pressure filtration plate and the extrusion plate; a plurality of through holes are circumferentially distributed on the circumferential side of the left part of the sleeve; the left end of the sleeve is closed and has a first convex ring, and the left side of the extrusion plate has a clamping groove matching the first convex ring.

[0020] In some embodiments of the present invention, the red mud pressure filtration equipment further includes:

[0021] A second convex ring is connected to the right end of the sleeve;

[0022] A placement cavity is located in the pressure filtration plate, the second convex ring is slidably connected with the placement cavity, and an air cavity is formed between the left side of the second convex ring and the placement cavity;

[0023] A second compressed air joint is communicated with the air cavity.

[0024] In some embodiments of the present invention, a plurality of sleeves are evenly distributed on the pressure filtration plate, and a discharge conveyor belt is arranged below the pressure filtration plate.

[0025] In some embodiments of the present invention, the top of the pressure filtration plate is connected with a first compressed air joint, and the bottom of the groove has a jet port communicated with the first compressed air joint.

[0026] In some embodiments of the present invention, the filtration equipment includes:

[0027] A filter box, having a liquid inlet and a liquid outlet, and the liquid outlet is located above the liquid inlet;

[0028] Baffles, detachably connected to the inner wall of the filter box;

[0029] Wherein, a plurality of baffles are longitudinally arranged in a staggered manner between the liquid inlet and the liquid outlet to form a flow channel that extends upward in a meandering manner.

[0030] In some embodiments of the present invention, the upper side of the baffle is inclined.

[0031] In some embodiments of the present invention, the ratio of the vertical distance from the liquid inlet to the bottom of the filter box to the height of the filter box is 1 / 6 - 1 / 5.

[0032] In some embodiments of the present invention, the inlet of the flow channel and the liquid inlet are located on opposite sides of the filter box.

[0033] The embodiments of the present invention have at least the following advantages or beneficial effects:

[0034] First, the filtrate first enters the filtrate tank through the filtrate inlet for storage, and then returns to the low-temperature digestion equipment through the filtrate outlet to achieve alkali recovery. The flue gas pipeline and the heat exchange water pipe perform heat exchange in the first heat exchange equipment to heat the industrial water or raw water in the heat exchange water pipe. The filtrate in the filtrate tank and the industrial water or raw water in the heat exchange water pipe achieve heat exchange through the second heat exchange equipment, so as to first heat the filtrate in the filtrate tank to 80 - 90 °C and then send it back to the low-temperature digestion equipment.

[0035] Second, under the filtration action of the filtration equipment, the particulate matter mixed in the filtrate can be filtered out to prevent these particulate matters from adhering to the corresponding conveying pipeline and causing blockage.

[0036] Third, the red mud pressure filtration equipment is connected to the flue gas pipeline through a shunt pipeline, and the shunt pipeline is used to introduce the flue gas into the red mud pressure filtration equipment to heat the filter cake after pressure filtration and improve the dehydration rate of the filter cake.

[0037] Other features and advantages of the present invention will be described in the subsequent description, and, in part, will become apparent from the description or be understood by implementing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0039] Figure 1 It is a process flow diagram of alumina production provided by the present application;

[0040] Figure 2 Structural schematic diagram of the flue gas waste heat utilization system provided for this application;

[0041] Figure 3 Structural schematic diagram of the filtration equipment provided for Embodiment 2;

[0042] Figure 4 Structural schematic diagram of the filtration equipment provided for Embodiment 3;

[0043] Figure 5 Structural schematic diagram of the filtration equipment provided for Embodiment 4;

[0044] Figure 6 Structural schematic diagram of the red mud pressure filtration equipment provided for Embodiment 5;

[0045] Figure 7 Structural schematic diagram of the filter plate;

[0046] Figure 8 For Figure 7 Partial enlarged view of position A in

[0047] Icon:

[0048] 1 - Flue gas pipeline, 2 - Heat exchange water pipe, 3 - First heat exchange equipment, 4 - Second heat exchange equipment, 5 - Filtrate tank, 51 - Filtrate inlet, 52 - Filtrate outlet,

[0049] 6 - Red mud pressure filtration equipment, 61 - Shunt pipeline, 62 - Fixed plate, 63 - Filter plate, 631 - Groove, 632 - Extrusion plate, 633 - Pressure filtration cavity, 634 - Mud inlet, 635 - Drainage port, 636 - Smoke exhaust port, 637 - Cigarette butt inlet, 638 - Connecting pipe, 639 - Sleeve, 641 - Through hole, 642 - First convex ring, 643 - First compressed air joint, 644 - Jet port, 645 - Second convex ring, 646 - Storage cavity, 647 - Second compressed air joint, 648 - Air cavity, 64 - Discharge conveyor belt,

[0050] 7 - Red mud washing equipment, 8 - Low - temperature digestion equipment, 9 - Filtration equipment, 91 - Filter box, 92 - Baffle, 93 - Flow channel, 94 - Liquid inlet, 95 - Liquid outlet. Detailed implementation manners

[0051] In the following, only some exemplary embodiments are briefly described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the embodiments of the present invention.

[0052] In the description of the embodiments of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "left", "right", "top", "bottom", "inner", "circumferential", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation on the embodiments of the present invention.

[0053] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, the meaning of "a plurality" is two or more unless otherwise specifically defined.

[0054] In the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0055] The embodiments of the present invention will be described in detail below.

[0056] Embodiment 1

[0057] See Figures 1 to 2 , this embodiment provides a flue gas waste heat utilization system, including a flue gas pipeline 1, a heat exchange water pipe 2, a first heat exchange device 3, a second heat exchange device 4, and a filtrate tank 5.

[0058] The flue gas pipeline 1 is used to transport flue gas with a first specified temperature. The flue gas includes, for example, flue gas at 600 - 900 °C generated by a roasting device for producing alumina. High-temperature flue gas from other sources is also possible.

[0059] The heat exchange water pipe 2 is used to transport industrial water or raw water.

[0060] The first heat exchange device 3 includes a vertical finned tube heat exchanger; the flue gas pipeline 1 and the heat exchange water pipe 2 pass through the first heat exchange device 3 to achieve heat exchange, so as to heat the industrial water or raw water in the heat exchange water pipe 2 to a second specified temperature. After the flue gas pipeline 1 passes through the first heat exchange device 3, it is filtered by a bag filter and then discharged to other treatment devices.

[0061] The second heat exchange device 4 includes a heat exchange jacket which is sleeved outside the filtrate tank 5; the second heat exchange device 4 is used to heat the filtrate in the filtrate tank 5 to 80 - 90 °C.

[0062] The filtrate tank 5 has a filtrate inlet 51 and a filtrate outlet 52; the filtrate inlet 51 is successively connected with a red mud pressure filtration device 6 for producing alumina, a red mud washing device 7 and a low - temperature digestion device 8; the filtrate outlet 52 is connected to the inlet of the low - temperature digestion device 8 through a filtration device 9.

[0063] Red mud is produced in the low - temperature digestion device 8. Specifically, during the alumina production process, after the bauxite is digested at low temperature, a mixed slurry of red mud and sodium aluminate is formed. Red mud mainly consists of solid residues formed by non - aluminum minerals in the bauxite during the digestion process. After the red mud is discharged from the bottom of the low - temperature digestion device 8 and undergoes washing and pressure filtration, the filtrate is obtained. The filtrate first enters the filtrate tank 5 through the filtrate inlet 51 for storage, and then returns to the low - temperature digestion device 8 through the filtrate outlet 52 to achieve alkali recovery. The flue gas pipeline 1 and the heat exchange water pipe 2 exchange heat in the first heat exchange device 3 to heat the industrial water or raw water in the heat exchange water pipe 2. The filtrate in the filtrate tank 5 exchanges heat with the industrial water or raw water in the heat exchange water pipe 2 through the second heat exchange device 4, so that the filtrate in the filtrate tank 5 is first heated to 80 - 90 °C and then sent back to the low - temperature digestion device 8. Under the filtration action of the filtration device 9, the particulate matter mixed in the filtrate can be filtered out to prevent these particulate matters from adhering to the corresponding conveying pipelines and causing blockage.

[0064] The red mud pressure filtration device 6 is connected to the flue gas pipeline 1 through a diversion pipeline. The diversion pipeline is used to introduce flue gas into the red mud pressure filtration device 6 to heat the filter cake after pressure filtration and improve the dehydration rate of the filter cake.

[0065] Embodiment 2

[0066] See Figures 1 to 3 , the filtration device 9 includes a filter box 91 and a baffle 92. The filter box 91 has a liquid inlet 94 and a liquid outlet 95, and the liquid outlet is located above the liquid inlet. The baffle 92 is detachably connected to the inner wall of the filter box 91 in a snap - fit, threaded connection or other ways; a plurality of baffles 92 are longitudinally arranged in a staggered manner between the liquid inlet and the liquid outlet to form a flow channel 92 that extends upward in a meandering manner.

[0067] The filtrate flows upward along the flow channel 92, while the particulate matter settles under the action of gravity and the blocking of the baffle 92, realizing solid - liquid separation, thereby preventing the particulate matter in the filtrate from entering the subsequent pipelines and causing pipeline blockage.

[0068] The baffle 92 is detachably connected to the inner wall of the filter box 91, which is convenient for the disassembly, installation and cleaning of the baffle 92.

[0069] In this embodiment, the liquid inlet is close to the bottom of the filter tank 91, and the liquid outlet is located at the upper part of the filter tank 91.

[0070] Embodiment 3

[0071] This embodiment is a further improvement based on Embodiment 2.

[0072] See Figures 1 to 4 , the upper side of the baffle 92 is inclined. In this way, the particulate matter sedimented on the upper side of the baffle 92 can roll down to the bottom of the filter tank 91, avoiding the influence on the size of the flow channel 92 and the flow rate of the liquid outlet due to the gradual accumulation of particulate matter on the baffle 92.

[0073] In this embodiment, the ratio of the vertical distance from the liquid inlet to the bottom of the filter tank 91 to the height of the filter tank 91 is 1 / 6 - 1 / 5. In this way, the position of the liquid inlet is appropriately raised to avoid the filtrate entering the filter tank 91 from the liquid inlet directly impacting the bottom of the filter tank 91, causing serious resuspension of the sediment.

[0074] In this embodiment, the inlet of the flow channel 92 and the liquid inlet are located on the same side of the filter tank 91.

[0075] Embodiment 4

[0076] See Figures 1 to 5 , different from Embodiment 3, in this embodiment, the inlet of the flow channel 92 and the liquid inlet are located on the opposite sides of the filter tank 91, that is, the inlet of the flow channel 92 is located on the left side of the filter tank 91, and the liquid inlet is located on the right side of the filter tank 91. In this way, the distance between the inlet of the flow channel 92 and the liquid inlet is relatively far. Even if there is still a slight resuspension of the sediment, the resuspended sediment is not easily directly introduced into the flow channel 92 from the inlet of the flow channel 92 under the blockage of the lowermost baffle 92.

[0077] Embodiment 5

[0078] See Figures 1 to 8 , in this embodiment, the red mud pressure filtration device 6 includes a fixing plate 62, a pressure filtration plate 63 and a discharge conveyor belt 64.

[0079] The fixing plate 62 is fixedly arranged at a specified position.

[0080] A plurality of filter pressing plates 63 are arranged horizontally and movably on the right side of the fixed plate 62. The left side of the filter pressing plate 63 has a groove 631, and a pressing plate 632 is slidably connected horizontally in the groove 631. The left side of the pressing plate 632 and the side wall of the groove 631 form a filter pressing cavity 633; the filter pressing plate 63 located on the leftmost side can be in contact with the right side of the fixed plate 62 to block the filter pressing cavity 633 of this filter pressing plate 63, and two adjacent filter pressing plates 63 can be in contact with each other to block the corresponding filter pressing cavity 633; the right side of the filter pressing plate 63 has a mud inlet 634 communicating with the filter pressing cavity 633, the lower part has a liquid discharge port 635 communicating with the filter pressing cavity 633, and the upper part has a smoke exhaust port 636 communicating with the filter pressing cavity 633. The liquid discharge port 635 is connected with a tobacco inlet 637 through a three-way joint, and the tobacco inlet 637 is connected with the shunt pipe 61.

[0081] The discharge conveyor belt 64 is arranged below the filter pressing plate 63.

[0082] The working principle of the red mud filter pressing device 6 is as follows: A plurality of filter pressing plates 63 are arranged horizontally and movably on the right side of the fixed plate 62. Push these filter pressing plates 63 from right to left so that the filter pressing plates 63 are in close contact with each other in turn, and between the fixed plate 62 and the leftmost filter pressing plate 63; after the red mud enters the filter pressing cavity 633 from the mud inlet 634, move the pressing plate 632 to the left to squeeze the liquid out of the red mud to obtain filtrate and filter cake. The filtrate is discharged from the liquid discharge port 635, and the filter cake is left in the filter pressing cavity 633; after the filtrate is completely discharged from the liquid discharge port 635, open the valve on the tobacco inlet 637 to allow high-temperature flue gas to enter the filter pressing cavity 633. The upward flow of the high-temperature flue gas causes the water remaining in the filter cake to evaporate and be discharged from the smoke exhaust port 636, thereby reducing the water content of the filter cake; subsequently, the filter pressing plates 63 are separated from each other, and between the fixed plate 62 and the leftmost filter pressing plate 63, and the filter cake drops downward onto the discharge conveyor belt 64 for transportation.

[0083] The red mud filter pressing device 6 further includes a connecting pipe 638 and a sleeve 639.

[0084] A connecting pipe 638 is connected inside the mud inlet 634, and the left end of the connecting pipe 638 extends into the groove 631.

[0085] The sleeve 639 is horizontally movably sleeved on the outer wall of the connecting pipe 638; the outer wall of the sleeve 639 is slidably connected with the filter pressing plate 63 and the pressing plate 632; a plurality of through holes 641 are circumferentially distributed on the left circumferential side surface of the sleeve 639; the left end of the sleeve 639 is closed and has a first convex ring 642, and the left side of the pressing plate 632 has a clamping groove matching with the first convex ring 642.

[0086] When the red mud enters the pressure filtration chamber 633, the red mud first enters the connecting pipe 638. The red mud will push the sleeve 639 to the left, causing the through hole 641 on the sleeve 639 to move leftward and expose from the extrusion plate 632 to open the through hole 641. Then the red mud enters the pressure filtration chamber 633 successively through the connecting pipe 638 and the through hole 641.

[0087] To facilitate the leftward movement of the extrusion plate 632, the top of the pressure filtration plate 63 is connected with a first compressed air joint 643. The bottom of the groove 631 has a jet port 644 communicating with the first compressed air joint 643. In this way, after connecting the first compressed air joint 643 with an external air source, the compressed gas enters between the bottom of the groove 631 and the right side of the extrusion plate 632, thus pushing the extrusion plate 632 to the left; when the extrusion plate 632 moves leftward, it can close the through hole 641 again and drive the sleeve 639 to move leftward together through the first convex ring 642.

[0088] The red mud pressure filtration device 6 further includes a second convex ring 645, a storage chamber 646 and a second compressed air joint 647.

[0089] The second convex ring 645 is connected to the right end of the sleeve 639.

[0090] The storage chamber 646 is located in the pressure filtration plate 63. The second convex ring 645 is slidably connected with the storage chamber 646, and an air chamber 648 is formed between the left side of the second convex ring 645 and the storage chamber 646.

[0091] The second compressed air joint 647 communicates with the air chamber 648.

[0092] After the extrusion plate 632 moves leftward to pressure-filter the red mud to form a filter cake, the first compressed air joint 643 is closed. After connecting the second compressed air joint 647 with an external air source, the compressed gas enters the air chamber 648, pushing the sleeve 639 to the left. The sleeve 639 knocks on a part of the filter cake, causing the filter cake to break up, which helps to reduce the water content of the filter cake by high-temperature flue gas subsequently.

[0093] Furthermore, multiple sleeves 639 are evenly distributed on the pressure filtration plate 63. In this way, the filter cake can be broken up evenly, and the crushed materials falling on the discharge conveyor belt 64 subsequently can be evenly distributed, avoiding adverse phenomena such as the deviation of the discharge conveyor belt 64.

[0094] Finally, it should be noted that: The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Without conflict, the embodiments of the present application and the features in the embodiments can be combined arbitrarily. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A flue gas waste heat utilization system, characterized in that: include: a flue gas duct for conveying flue gas having a first specified temperature; Hot water exchange pipes, used to transport industrial water or raw water; a first heat exchange device, wherein the flue gas duct and the hot water exchange pipe are subjected to heat exchange by the first heat exchange device, so as to heat the industrial water or raw water in the hot water exchange pipe to a second specified temperature; The second heat exchange device is used to heat the filtrate in the filtrate tank to 80-90°C; The filtrate tank has a filtrate inlet and a filtrate outlet; the filtrate inlet is sequentially connected to a red mud filter press device, a red mud washing device and a low-temperature dissolution device for producing alumina; the filtrate outlet is connected to the inlet of the low-temperature dissolution device through a filtering device; The red mud filter press equipment is connected to the flue gas pipeline via a shunt pipeline, and the shunt pipeline is used to introduce the flue gas into the red mud filter press equipment to heat the filter cake after filtration and improve the dehydration rate of the filter cake.

2. The flue gas waste heat utilization system according to claim 1, characterized in that: The red mud filter press equipment comprises a fixed plate and a filter press plate; A plurality of filter press plates are arranged in a transversely movable manner on the right side of the fixed plate; a groove is provided on the left side of the filter press plate, a pressing plate is transversely slidably connected in the groove, and a filter press chamber is formed between the left side of the pressing plate and the side wall of the groove; The filter press plate located on the far left can contact with the right side of the fixed plate to block the filter press cavity of the filter press plate, and two adjacent filter press plates can contact with each other to block the corresponding filter press cavities; The right side of the filter press plate has a mud inlet connected to the filter press chamber, the lower part has a liquid discharge port connected to the filter press chamber, and the upper part has a smoke exhaust port connected to the filter press chamber. The liquid discharge port is connected to a cigarette inlet head, and the cigarette inlet head is connected to the diversion pipe.

3. The flue gas waste heat utilization system according to claim 2, characterized in that: The red mud filter press equipment also includes: A connecting pipe connected to the mud inlet, wherein the left end of the connecting pipe extends into the groove; A sleeve is movably sleeved laterally on the outer wall of the connecting tube; the outer wall of the sleeve is slidably connected with the filter plate and the extrusion plate; a plurality of through holes are circumferentially distributed on the left circumferential side surface of the sleeve; the left end of the sleeve is closed and has a first convex ring, and the left side of the extrusion plate has a groove matching the first convex ring.

4. The flue gas waste heat utilization system according to claim 3, characterized in that: The red mud filter press equipment also includes: A second convex ring connected to the right end of the sleeve; A storage cavity is located in the filter press plate, the second convex ring is slidably connected to the storage cavity, and an air cavity is formed between the left side of the second convex ring and the storage cavity; The second compressed air connector is communicated with the air cavity.

5. The flue gas waste heat utilization system according to claim 4, characterized in that: The plurality of sleeves are evenly distributed on the filter press plate, and a discharge conveyor belt is arranged below the filter press plate.

6. The flue gas waste heat utilization system according to claim 3, characterized in that: The top of the filter press plate is connected with a first compressed air connector, and the bottom of the groove is provided with an air jet port connected with the first compressed air connector.

7. The flue gas waste heat utilization system according to any one of claims 1 to 6, characterized in that: The filtering device comprises: A filter box having a liquid inlet and a liquid outlet, wherein the liquid outlet is located above the liquid inlet; a baffle, detachably connected to the inner wall of the filter box; Wherein, a plurality of baffles are arranged in a longitudinally staggered manner between the liquid inlet and the liquid outlet to form a flow channel extending upwardly in a winding manner.

8. The flue gas waste heat utilization system according to claim 7, characterized in that: The upper side of the baffle is arranged inclined.

9. The flue gas waste heat utilization system according to claim 7, characterized in that: The ratio of the vertical distance from the liquid inlet to the bottom of the filter box to the height of the filter box is 1 / 6 to 1 / 5.

10. The flue gas waste heat utilization system according to claim 9, characterized in that: The inlet of the flow channel and the liquid inlet are located on opposite sides of the filter box.

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