Flue gas treatment system for roasting furnace

Abstract

The invention belongs to the technical field of high-temperature flue gas treatment, and discloses a flue gas treatment system for a roasting furnace, which comprises a desulfurization tower, a shell-and-tube heat exchanger, a fin heat exchanger, a pump body and a spray head, the spray head is mounted at the upper part of a cavity of the desulfurization tower, and the top of the desulfurization tower is fixedly communicated with an exhaust port; a shell air inlet and a shell air outlet which are communicated with each other are formed in the shell-and-tube heat exchanger. According to the scheme, slurry at the bottom of the desulfurizing tower is pumped out by operating the pump body and enters the shell part of the fin type heat exchanger through the fourth pipeline and the shell liquid inlet, and normal-temperature liquid in the heat exchange pipe part of the fin type heat exchanger is subjected to heat exchange and preheating in a liquid-liquid heat exchange mode; at the moment, the slurry sprayed downwards and the flue gas flowing upwards are subjected to efficient heat exchange in a direct contact manner, and sulfur oxides in the flue gas are absorbed, so that the effects of saving energy and cooling the slurry and preheating normal-temperature liquid are achieved.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature flue gas treatment technology, specifically a flue gas treatment system for a roasting furnace. Background Technology

[0002] A roasting furnace is an industrial furnace used to heat ores, concentrates, or other solid materials under conditions of air isolation or limited air supply. During operation, it generates gases such as sulfur oxides and nitrogen oxides, which must be treated before being released.

[0003] The initial flue gas temperature discharged from the roasting furnace is very high (up to 800-1000℃). The flue gas first recovers heat through a heat exchanger, and then it is sent to the desulfurization tower for treatment. However, the flue gas temperature is still high during this process (around 200℃). At this time, the high-temperature flue gas will exchange heat with the alkaline slurry in the desulfurization tower, causing the temperature of the alkaline slurry to rise rapidly. This leads to a decrease in the absorption efficiency of the alkaline slurry for sulfur oxides in the flue gas. Therefore, the operators need to configure a corresponding cooling system in the desulfurization tower, which will cause a sharp increase in energy consumption.

[0004] For the room-temperature liquid (20°C) that initially enters the heat exchanger, its low temperature will cause it to interact with the flue gas entering the heat exchanger, resulting in a rapid temperature change in the metal material of the heat exchanger, which will generate stress and lead to metal fatigue and damage.

[0005] Therefore, in order to solve the above problems, a flue gas treatment system for roasting furnaces is proposed. Summary of the Invention

[0006] To address the problems mentioned in the background section, this invention provides a flue gas treatment system for a roasting furnace, which solves the problems of high energy consumption in existing flue gas treatment systems and the easy damage to heat exchangers in waste heat recovery equipment due to the synergistic effect of high-temperature flue gas and low-temperature liquid.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a flue gas treatment system for a roasting furnace, comprising a desulfurization tower, a shell-and-tube heat exchanger, a finned heat exchanger, a pump body, and a nozzle. The nozzle is installed on the upper part of the desulfurization tower cavity. An exhaust port is fixedly connected to the top of the desulfurization tower. The shell-and-tube heat exchanger is provided with a shell air inlet and a shell air outlet that are interconnected, as well as a tube liquid inlet and a tube liquid outlet. An exhaust gas pipe connected to the middle of the desulfurization tower is installed on the shell air outlet. The finned heat exchanger is provided with a tube body inlet 2 and a tube body outlet 2 that are interconnected, as well as a shell inlet and a shell outlet. A pipe 2 is fixedly connected to the shell outlet, and the other end of the pipe 2 is connected to the nozzle. The tube body outlet 2 and the tube body inlet 1 are connected through a pipe. The pump body has an input end and an output end in pipe three and pipe four, respectively. The other end of pipe three is connected to the bottom cavity of the desulfurization tower, and the other end of pipe four is connected to the liquid inlet of the shell. The exhaust pipe is located inside the desulfurization tower with its outlet facing downwards, and the bottom of the desulfurization tower stores slurry.

[0008] Preferably, a plurality of demisters are equidistantly arranged on the exhaust port.

[0009] Preferably, the desulfurization tower is equipped with a heat insulation component to prevent the upper wall of the desulfurization tower from contacting hot gas.

[0010] Preferably, the heat insulation component includes a flow guide ring located at the top of the desulfurization tower cavity and fixedly sleeved at the bottom of the exhaust port, and an annular cylinder located on the outer periphery of the flow guide ring is fixedly installed at the top of the exhaust pipe cavity, with a gap between the upper surface of the flow guide ring and the bottom of the annular cylinder. A branch pipe is also connected to the second pipe, and the other end of the branch pipe is located above the heat insulation component and connected to the top of the desulfurization tower cavity.

[0011] Preferably, the annular cylinder and the portion of the guide ring located below it overlap in the vertical direction, and the outer diameter of the bottommost end of the guide ring is smaller than the inner diameter of the annular cylinder.

[0012] Preferably, the bottom of the desulfurization tower cavity is also provided with a gas guide located above the outlet end of the waste gas pipe; The gas guiding component includes a second guiding ring and a funnel component fixed inside the desulfurization tower. There is a gap between the bottom of the second guiding ring and the bottom of the funnel component, and the gap is larger than the gap between the first guiding ring and the annular cylinder. The bottom outer diameter of the funnel component is larger than the bottom outer diameter of the guide ring.

[0013] Preferably, a circular plate is fixedly installed on the top of the second guide ring, and a plurality of fan blades are provided on the circular plate.

[0014] Preferably, a support is also provided at the lower part of the desulfurization tower cavity, and an anti-cavitation mechanism located below the exhaust gas pipe outlet is installed on the support.

[0015] Preferably, the anti-cavitation mechanism includes a limiting rod fixedly installed in the middle of the bracket, a counterweight rod vertically movably sleeved on the outer periphery of the limiting rod, a spring combination ring movably sleeved on the outer periphery of the counterweight rod, the top end of the spring portion of the spring combination ring being fixedly connected to the step on the counterweight rod, a plurality of connecting rods one being hinged in a ring array at the bottom end of the counterweight rod, a connecting rod two being hinged in the middle of the connecting rod one, the top end of the connecting rod two being hinged to the spring combination ring, and a corrosion-resistant elastic membrane covering the outer periphery of the counterweight rod; The bottom end of the counterweight rod is bonded to the inner wall of the corrosion-resistant elastic membrane; one end of the connecting rod is rotatably connected to a roller for supporting the inner wall of the corrosion-resistant elastic membrane.

[0016] Preferably, the outer periphery of the corrosion-resistant elastic membrane and the portion located below the connecting rod are provided with a plurality of ribs in an annular array.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The above scheme involves feeding room-temperature liquid into the heat exchange tubes of the finned heat exchanger through the second inlet of the tube body. The pump extracts the slurry from the bottom of the desulfurization tower and feeds it into the shell of the finned heat exchanger through the fourth pipe and the shell inlet. The room-temperature liquid in the heat exchange tubes of the finned heat exchanger is preheated through liquid-liquid heat exchange. The preheated liquid then enters the heat exchange tubes of the tube-and-shell heat exchanger through the second outlet of the tube body, the pipe, and the first inlet of the tube body. High-temperature flue gas enters the shell of the tube-and-shell heat exchanger through the shell inlet and is output to the desulfurization tower through the shell outlet and the exhaust pipe. Meanwhile, the slurry in the shell of the finned heat exchanger is re-sprayed through the shell outlet and the nozzle and enters the desulfurization tower. At this time, the downward sprayed slurry directly contacts the upward flowing flue gas for efficient heat exchange and absorbs sulfur oxides in the flue gas, thereby achieving energy-saving cooling of the slurry and preheating of the room-temperature liquid. The above scheme allows the slurry to flow back into the space between the guide ring and the annular cylinder through the branch pipe and leave through the gap between them, forming an annular water curtain wall. At this time, the flue gas discharged through the exhaust pipe and the slurry sprayed through the nozzle will undergo efficient heat exchange and chemical absorption reaction in the annular water curtain wall. The water curtain formed can also absorb the heat of the flue gas and the nitrogen oxides therein, thereby avoiding the situation where the flue gas flowing in the desulfurization tower comes into contact with the inner wall of the desulfurization tower and conducts heat to the outside, resulting in heat waste. The above-mentioned solution utilizes a corrosion-resistant elastic membrane and a portion thereof that initially float on the liquid surface. When the pump extracts slurry, it blocks the vortex generated by the slurry in the desulfurization tower. As the vortex intensifies, its suction increases, and the corrosion-resistant elastic membrane is attracted by the vortex, causing the counterweight rod to descend. Since the diameter of the vortex decreases as it deepens, the counterweight rod, under the influence of slurry pressure and buoyancy, forces several connecting rods to rotate in opposite directions. This, in turn, pushes the spring assembly ring through connecting rod two, compressing and storing its spring portion. This allows the device to follow the changes in the vortex diameter, avoiding situations where excessive vortex coverage leads to increased energy consumption, or where insufficient vortex coverage fails to effectively reduce the gas extracted by the pump. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the frontal planar structure of the present invention; Figure 2 This is a frontal perspective view of the present invention; Figure 3 This is a front cross-sectional view of the desulfurization tower of the present invention; Figure 4 for Figure 3 Enlarged view of point A in the middle; Figure 5 for Figure 3 Enlarged view of point B in the middle; Figure 6 This is a schematic diagram of the circular plate of the present invention; Figure 7 This is a schematic diagram of the structure of the bracket of the present invention; Figure 8 This is a front cross-sectional view of the elastic film of the present invention; Figure 9 This is a front cross-sectional view of the counterweight rod of the present invention.

[0019] In the diagram: 1. Shell and tube heat exchanger; 11. Shell air inlet; 12. Shell air outlet; 13. Tube liquid inlet 1; 14. Tube liquid outlet 1; 2. Finned heat exchanger; 21. Tube liquid inlet 2; 22. Tube liquid outlet 2; 23. Shell liquid inlet; 24. Shell liquid outlet; 3. Desulfurization tower; 31. Exhaust gas pipe; 32. Pipe 2; 321. Branch pipe; 33. Exhaust port; 331. Demister; 34. Support frame; 4. Pump body; 41. Pipeline 3; 42. Pipeline 4; 5. Heat insulation component; 51. Flow guide ring 1; 52. Annular cylinder; 6. Air guide component; 61. Flow guide ring 2; 611. Circular plate; 612. Fan blade; 62. Funnel component; 7. Anti-cavitation mechanism; 71. Limiting rod; 72. Counterweight rod; 73. Connecting rod 1; 731. Roller; 74. Connecting rod 2; 75. Spring combination ring; 76. Corrosion-resistant elastic membrane; 8. Nozzle. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] like Figures 1 to 9 As shown, the present invention provides a flue gas treatment system for a roasting furnace, including a desulfurization tower 3, a shell and tube heat exchanger 1, a finned heat exchanger 2, a pump body 4, and a nozzle 8. The nozzle 8 is installed on the upper part of the cavity of the desulfurization tower 3. An exhaust port 33 is fixedly connected to the top of the desulfurization tower 3. The shell and tube heat exchanger 1 is provided with a shell air inlet 11 and a shell air outlet 12 that are interconnected, as well as a tube liquid inlet 13 and a tube liquid outlet 14. An exhaust pipe 31 that is connected to the middle of the desulfurization tower 3 is installed on the shell air outlet 12. The finned heat exchanger 2 is provided with a tube body inlet 21 and a tube body outlet 22 that are interconnected, as well as a shell inlet 23 and a shell outlet 24. A pipe 32 is fixedly connected to the shell outlet 24, and the other end of the pipe 32 is connected to the nozzle 8. The tube body outlet 22 and the tube body inlet 13 are connected through the pipe. The input end and output end of the pump body 4 are respectively pipe 3 41 and pipe 42. The other end of pipe 3 41 is connected to the bottom cavity of the desulfurization tower 3, and the other end of pipe 42 is connected to the liquid inlet 23 of the shell. The exhaust pipe 31 has one end with its outlet facing downward inside the desulfurization tower 3, and the bottom of the desulfurization tower 3 stores slurry. Several demisters 331 are equidistantly arranged on the exhaust port 33.

[0022] Using the above scheme, ambient temperature liquid is introduced into the heat exchange tubes of the finned heat exchanger 2 through the tube inlet 21. Pump 4 draws out the slurry from the bottom of the desulfurization tower 3 and introduces it into the shell portion of the finned heat exchanger 2 through pipe 42 and shell inlet 23. After preheating the ambient temperature liquid in the heat exchange tube portion of the finned heat exchanger 2 via liquid-liquid heat exchange, the preheated liquid enters the heat exchange tubes of the shell-and-tube heat exchanger 1 through the tube outlet 22, pipe, and tube inlet 13. High-temperature flue gas enters the shell portion of the tube heat exchanger 1 through the shell inlet 11 and is output to the desulfurization tower 3 through the shell outlet 12 and the exhaust pipe 31. Meanwhile, the slurry in the shell of the finned heat exchanger 2 is re-sprayed through the shell outlet 24 and the nozzle 8 and enters the desulfurization tower 3. At this time, the downward sprayed slurry directly contacts the upward flowing flue gas for efficient heat exchange and absorbs sulfur oxides in the flue gas, thereby achieving energy-saving cooling of the slurry and preheating of the room temperature liquid. It is worth noting that the downward-facing outlet of the exhaust pipe 31 allows the flue gas initially entering the desulfurization tower 3 to come into contact with the slurry and react, thus improving the heat exchange and desulfurization effect of the flue gas.

[0023] like Figures 2-5 As shown, the desulfurization tower 3 is equipped with a heat insulation component 5 to prevent the upper wall of the desulfurization tower 3 from contacting the hot gas. The heat insulation component 5 includes a guide ring 51 located at the top of the desulfurization tower 3 cavity and fixedly sleeved at the bottom of the exhaust port 33. An annular cylinder 52 located on the outer periphery of the guide ring 51 is fixedly installed at the top of the exhaust pipe 31 cavity. A gap is left between the upper surface of the guide ring 51 and the bottom of the annular cylinder 52. A branch pipe 321 is also connected to the second pipe 32. The other end of the branch pipe 321 is located above the heat insulation component 5 and is connected to the top of the desulfurization tower 3 cavity. Using the above scheme, the slurry that flows back will also enter the space between the guide ring 51 and the annular cylinder 52 through the branch pipe 321 and leave through the gap between them, forming an annular water curtain wall. At this time, the flue gas discharged through the exhaust pipe 31 and the slurry sprayed through the nozzle 8 will undergo efficient heat exchange and chemical absorption reaction in the annular water curtain wall. The water curtain formed can also absorb the heat of the flue gas and the nitrogen oxides therein, thereby avoiding the situation where the flue gas flowing in the desulfurization tower 3 contacts the inner wall of the desulfurization tower 3 and conducts heat to the outside, resulting in heat waste. It is worth noting that the annular cylinder 52 and the guide ring 51 located below it overlap in the vertical direction, and the outer diameter of the bottom of the guide ring 51 is smaller than the inner diameter of the annular cylinder 52. At this time, the slurry discharged through the gap will converge at the bottom of the guide ring 51, thus making the formed annular water curtain wall more stable and thick.

[0024] like Figure 2 , Figure 3 , Figure 5 and Figure 6 As shown, a gas guide 6 is also provided at the bottom of the desulfurization tower 3 chamber, located above the outlet end of the exhaust pipe 31; The gas guiding component 6 includes a second guiding ring 61 and a funnel component 62 fixed in the desulfurization tower 3. There is a gap between the bottom of the second guiding ring 61 and the bottom of the funnel component 62, and the gap is larger than the gap between the first guiding ring 51 and the annular cylinder 52. The bottom outer diameter of the funnel component 62 is larger than the bottom outer diameter of the first guide ring 51; a circular plate 611 is fixedly installed on the top of the second guide ring 61, and several fan blades 612 are provided on the circular plate 611. By adopting the above scheme, through the setting of the second guide ring 61 and the funnel component 62, when the annular water curtain formed by the heat insulation component 5 is blocked and cut off by the pipe end of the exhaust pipe 31, the gap between the second guide ring 61 and the funnel component 62 is sealed by the sealing slurry, thereby reducing the occurrence of gas entering the annular water curtain wall and the inner wall of the desulfurization tower 3 through the gap between the second guide ring 61 and the funnel component 62. At the same time, the top of the second guide ring 61 directly guides the gas discharged from the exhaust pipe 31 into the annular water curtain wall, further increasing the effect of the heat insulation component 5. When the flue gas passes through the fan blade 612, it will drive the fan blade 612 to rotate and generate turbulence, so that the sprayed slurry and the flue gas can come into more full contact in the turbulent space.

[0025] like Figure 3 , Figure 5 , Figure 7 and Figure 9 As shown, a support 34 is also provided at the lower part of the desulfurization tower 3 cavity, and an anti-cavitation mechanism 7 located below the outlet of the exhaust pipe 31 is installed on the support 34. The anti-cavitation mechanism 7 includes a limiting rod 71 fixedly installed in the middle of the bracket 34. A counterweight rod 72 is vertically movably sleeved on the outer periphery of the limiting rod 71. A spring combination ring 75 is movably sleeved on the outer periphery of the counterweight rod 72. The top end of the spring part on the spring combination ring 75 is fixedly connected to the step on the counterweight rod 72. Several connecting rods 73 are hinged in a ring array at the bottom end of the counterweight rod 72. A connecting rod 74 is hinged in the middle of the connecting rod 73. The top end of the connecting rod 74 is hinged to the spring combination ring 75. The counterweight rod 72 is wrapped with a corrosion-resistant elastic membrane 76. The bottom end of the counterweight rod 72 is bonded to the inner wall of the corrosion-resistant elastic membrane 76; one end of the connecting rod 73 is rotatably connected to a roller 731 for supporting the inner wall of the corrosion-resistant elastic membrane 76. A number of ribs are arranged in a ring array on the outer periphery of the corrosion-resistant elastic membrane 76 and below the connecting rod 73. Using the above scheme, the corrosion-resistant elastic membrane 76 and its inner part initially float on the liquid surface and block the vortex generated by the slurry in the desulfurization tower 3 when the pump body 4 draws slurry. When the vortex intensifies, its suction will increase, and the corrosion-resistant elastic membrane 76 will be attracted by the vortex and drive the counterweight rod 72 downward. Since the diameter of the vortex becomes smaller as it goes deeper, the counterweight rod 72 will be forced to rotate in opposite directions by the slurry pressure and buoyancy during its descent. This will push the spring combination ring 75 to move through the connecting rod 74 and compress and store the spring part, thus achieving the effect that the device can follow the change of the vortex diameter. This avoids the situation where the vortex coverage is too large, which would lead to an increase in equipment energy consumption, and the situation where the vortex coverage area is too small, which would not effectively reduce the gas drawn by the pump body 4. The ribs allow the corrosion-resistant elastic membrane 76 and internal counterweight rods 72 to rotate with the vortex, and reduce the resistance between the vortex and the corrosion-resistant elastic membrane 76 when the vortex rotates. It is worth noting that the corrosion-resistant elastic membrane 76 can be made of PTFE or PTFE composite membrane, which can almost completely withstand all media in the desulfurization tower, and the material can work for a long time at -190°C to +260°C, completely covering the working conditions of the desulfurization tower.

[0026] Working principle and usage process of this invention: First, room temperature liquid is input through pipe inlet 21 and enters the heat exchange tubes in finned heat exchanger 2. Pump 4 extracts the slurry from the bottom of desulfurization tower 3 through pipe 3 41 and enters the shell part of finned heat exchanger 2 through pipe 42 and shell inlet 23. After the room temperature liquid in the heat exchange tube part of finned heat exchanger 2 is preheated by liquid-liquid heat exchange, the preheated liquid enters the heat exchange tubes in tube heat exchanger 1 through pipe outlet 22, pipe and pipe inlet 13. At this time, high temperature flue gas enters the shell part of tube heat exchanger 1 through shell inlet 11 and is output to desulfurization tower 3 through shell outlet 12 and exhaust pipe 31. The slurry in the shell of finned heat exchanger 2 will be sprayed again through shell outlet 24 and nozzle 8 and enter desulfurization tower 3. At this time, the downward sprayed slurry has direct contact with the upward flowing flue gas for efficient heat exchange and absorbs sulfur oxides in the flue gas. The returned slurry will also enter the space between the guide ring 51 and the annular cylinder 52 through the branch pipe 321 and leave through the gap between them, forming an annular water curtain wall. At this time, the flue gas discharged through the exhaust pipe 31 and the slurry sprayed through the nozzle 8 will undergo efficient heat exchange and chemical absorption reaction in the annular water curtain wall. The water curtain formed can also absorb the heat of the flue gas and the nitrogen oxides therein, thereby avoiding the situation where the flue gas flowing in the desulfurization tower 3 comes into contact with the inner wall of the desulfurization tower 3 and conducts heat to the outside, resulting in heat waste. When the pump body 4 draws slurry from the bottom of the desulfurization tower 3 chamber, it will cause a vortex in the slurry at the bottom of the desulfurization tower 3. The corrosion-resistant elastic membrane 76 and part of it will float on the liquid surface and block the top of the vortex. When the vortex intensifies, its suction will increase, and the corrosion-resistant elastic membrane 76 will be attracted by the vortex and drive the counterweight rod 72 downward. Since the diameter of the vortex is smaller as it goes deeper, the counterweight rod 72 will be forced to rotate in opposite directions by the slurry pressure and buoyancy during its descent. This will push the spring combination ring 75 to move through the connecting rod 74 and compress and store the spring part, thus achieving the effect of the device following the change of the vortex diameter. This avoids the situation where the vortex coverage is too large, which would increase the energy consumption of the equipment, or the situation where the vortex coverage area is too small, which would not effectively reduce the gas drawn by the pump body 4.

[0027] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0028] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A flue gas treatment system for a roasting furnace, comprising a desulfurization tower (3), a tube heat exchanger (1), a finned heat exchanger (2), a pump body (4), and a nozzle (8), wherein the nozzle (8) is installed on the upper part of the cavity of the desulfurization tower (3), and an exhaust port (33) is fixedly connected to the top of the desulfurization tower (3), characterized in that: The shell-and-tube heat exchanger (1) is provided with a shell air inlet (11) and a shell air outlet (12) that are interconnected, as well as a tube liquid inlet (13) and a tube liquid outlet (14). The shell air outlet (12) is equipped with a waste gas pipe (31) that is connected to the middle of the desulfurization tower (3). The finned heat exchanger (2) is provided with a tube body inlet 2 (21) and a tube body outlet 2 (22) that are interconnected, as well as a shell inlet 23 and a shell outlet 24. A pipe 2 (32) is fixedly connected to the shell outlet 24, and the other end of the pipe 2 (32) is connected to the nozzle (8). The tube body outlet 2 (22) and the tube body inlet 1 (13) are connected through a pipe. The input end and output end of the pump body (4) are pipe three (41) and pipe four (42) respectively. The other end of pipe three (41) is connected to the bottom cavity of the desulfurization tower (3), and the other end of pipe four (42) is connected to the liquid inlet (23) of the shell. The exhaust pipe (31) is located inside the desulfurization tower (3) with one end of its outlet facing downwards, and the bottom of the desulfurization tower (3) stores slurry.

2. The flue gas treatment system for a roasting furnace according to claim 1, characterized in that: Several demisters (331) are equidistantly arranged on the exhaust port (33).

3. The flue gas treatment system for a roasting furnace according to claim 1, characterized in that: The desulfurization tower (3) is equipped with a heat insulation component (5) to prevent the upper wall of the desulfurization tower (3) from contacting hot gas.

4. The flue gas treatment system for a roasting furnace according to claim 3, characterized in that: The heat insulation component (5) includes a flow guide ring (51) located at the top of the cavity of the desulfurization tower (3) and fixedly sleeved at the bottom of the exhaust port (33). An annular cylinder (52) located on the outer periphery of the flow guide ring (51) is fixedly installed at the top of the cavity of the exhaust pipe (31). A gap is left between the upper surface of the flow guide ring (51) and the bottom of the annular cylinder (52). A branch pipe (321) is also connected to the second pipe (32). The other end of the branch pipe (321) is located above the heat insulation component (5) and is connected to the top of the cavity of the desulfurization tower (3).

5. The flue gas treatment system for a roasting furnace according to claim 4, characterized in that: The portion of the annular cylinder (52) and the portion of the guide ring (51) located below it overlaps in the vertical direction, and the outer diameter of the bottom end of the guide ring (51) is smaller than the inner diameter of the annular cylinder (52).

6. The flue gas treatment system for a roasting furnace according to claim 5, characterized in that: The bottom of the desulfurization tower (3) cavity is also provided with a gas guide (6) located above the outlet end of the exhaust pipe (31). The gas guiding component (6) includes a second guiding ring (61) and a funnel component (62) fixed in the desulfurization tower (3). There is a gap between the bottom of the second guiding ring (61) and the bottom of the funnel component (62), and the gap is larger than the gap between the first guiding ring (51) and the annular cylinder (52). The bottom outer diameter of the funnel component (62) is larger than the bottom outer diameter of the guide ring (51).

7. The flue gas treatment system for a roasting furnace according to claim 6, characterized in that: A circular plate (611) is fixedly installed on the top of the second guide ring (61), and a number of fan blades (612) are provided on the circular plate (611).

8. The flue gas treatment system for a roasting furnace according to claim 1, characterized in that: The lower part of the cavity of the desulfurization tower (3) is also provided with a support (34), and an anti-cavitation mechanism (7) located below the outlet of the exhaust pipe (31) is installed on the support (34).

9. The flue gas treatment system for a roasting furnace according to claim 8, characterized in that: The anti-cavitation mechanism (7) includes a limiting rod (71) fixedly installed in the middle of the bracket (34). A counterweight rod (72) is vertically movably sleeved on the outer periphery of the limiting rod (71). A spring combination ring (75) is movably sleeved on the outer periphery of the counterweight rod (72). The top end of the spring part on the spring combination ring (75) is fixedly connected to the step on the counterweight rod (72). Several connecting rods (73) are hinged in a ring array at the bottom end of the counterweight rod (72). A connecting rod (74) is hinged in the middle of the connecting rod (73). The top end of the connecting rod (74) is hinged to the spring combination ring (75). The counterweight rod (72) is wrapped with a corrosion-resistant elastic membrane (76). The bottom end of the counterweight rod (72) is bonded to the inner wall of the corrosion-resistant elastic membrane (76); One end of the connecting rod (73) is rotatably connected to a roller (731) for supporting the inner wall of the corrosion-resistant elastic membrane (76).

10. The flue gas treatment system for a roasting furnace according to claim 9, characterized in that: The outer periphery of the corrosion-resistant elastic membrane (76) and the portion below the connecting rod (73) are provided with several ribs in a ring array.

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