System for treating off-gas from a smelting furnace

Abstract

The present application relates to smelting furnace tail gas treatment technical field, especially to be used for smelting furnace tail gas treatment system.Its technical scheme includes that the fuming furnace tail exhaust electric precipitator and sulfuric acid tail exhaust electric precipitator are connected with the SCR denitration system through the first connecting pipe, the second connecting pipe.The present application utilizes the cooperation of the structures such as branch pipe, multiple groups of valves, sampling pipe, detection mechanism and control mechanism, first, the first valve, the second valve and the third valve are added in the connecting pipe, the valves are closed when the acid making system is shut down for maintenance, the system is independently isolated, and the smoke backflow and stream mixing are avoided;second, the bypass flue is formed by branch pipe, the second valve is closed, and the third valve is opened when the denitration system is maintained or the tail gas nitrogen oxide reaches the standard, so that the standard smoke is directly discharged, the denitration equipment is not needed to be started, the full line shutdown is avoided, the energy consumption is reduced, the problems of smoke backflow, maintenance shutdown and high energy consumption are completely solved, the tail gas desulfurization and denitration system operation is more stable, the adjustment is more flexible, and the environmental protection emission is controllable.

Description

Technical Field

[0001] This invention relates to the field of smelting furnace exhaust gas treatment technology, and more particularly to a smelting furnace exhaust gas treatment system. Background Technology

[0002] Currently, during the plant's production operation, the process exhaust gas generated from the acid production process undergoes desulfurization purification and is directly fed into the main flue gas pipeline for deep denitrification treatment by the downstream SCR denitrification system. Figure 1 The diagram shows the overall process flow of the furnace exhaust gas treatment system before its modification.

[0003] There are two core process defects in the existing flue gas transmission pipeline layout. First, the flue gas pipeline at the tail gas desulfurization outlet lacks a dedicated control valve. When the acid production system is shut down for maintenance, the desulfurization flue gas from the fuming furnace is highly susceptible to backflow and cross-flow, easily leading to excessive environmental emissions and posing significant safety hazards. Furthermore, it prevents the acid production system from being independently isolated from the fuming furnace desulfurization system, making it impossible to effectively prevent cross-flow of flue gas. Second, the desulfurization outlet of the fuming furnace lacks a bypass flue, forcing all desulfurized flue gas to flow directly into the denitrification system. Once the denitrification equipment undergoes maintenance, the entire production line must be shut down; even if the nitrogen oxide levels in the flue gas meet environmental emission standards, the denitrification equipment still needs to be forcibly activated, increasing overall energy consumption and severely restricting production continuity.

[0004] Therefore, this application proposes a system for treating exhaust gas from a smelting furnace. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the background art by proposing a system for treating exhaust gas from smelting furnaces.

[0006] The technical solution of this invention is for a smelting furnace tail gas treatment system, including a fume extraction electrostatic precipitator and a sulfuric acid tail gas electrostatic precipitator connected to an SCR denitrification system via a first connecting pipe and a second connecting pipe. The SCR denitrification system is also equipped with a large chimney connected via a third connecting pipe. The system further includes: a branch pipe installed in the middle of the third connecting pipe and the first connecting pipe to connect the two pipes; a third valve installed on the branch pipe; a second valve installed on the first connecting pipe; and a first valve installed on the second connecting pipe; and a sampling pipe fixedly connected to the outer wall of the first connecting pipe, the first connecting pipe being used for supplying nitrogen oxide flue gas; the sampling pipe being equipped with a detection mechanism corresponding to the nitrogen oxide concentration.

[0007] Optionally, the detection mechanism includes an insertion-type pipeline gas detector installed on the sampling tube. The outer wall of the sampling tube is provided with a first controller. The output end of the first controller is electrically connected to a third valve, and the input end of the first controller is electrically connected to the insertion-type pipeline gas detector.

[0008] Optionally, the detection mechanism further includes a hydraulic cylinder fixedly connected to the end of the sampling tube away from the first connecting tube. The piston rod of the hydraulic cylinder moves through the sampling tube. A pair of sealing plates are slidably provided inside the sampling tube. A connecting rod is fixedly connected to the middle of the sealing plate. One of the sealing plates is fixedly connected to the piston rod of the hydraulic cylinder. The sampling tube is also provided with a temperature measuring mechanism.

[0009] Optionally, the temperature measuring mechanism includes a temperature sensor mounted on the sampling tube, and the outer wall of the sampling tube is also provided with a second controller. The output end of the second controller is electrically connected to the hydraulic cylinder, and the input end of the second controller is electrically connected to the temperature sensor.

[0010] Optionally, a water-cooling coil is fitted on the outer wall of the sampling tube, and the water-cooling coil is correspondingly arranged with a pair of sealing plugs inside the sampling tube.

[0011] Optionally, a pair of sealing plates are arranged symmetrically with respect to the connecting rod.

[0012] Optionally, one of the sealing plates is extended into the first connecting pipe by a hydraulic cylinder, and the other sealing plate is located in the sampling pipe by a hydraulic cylinder.

[0013] Optionally, the sampling tube has several exhaust micro-holes at the end away from the first connecting tube.

[0014] Optionally, the sealing plate is interference-fitted with the inner wall of the sampling tube.

[0015] Optionally, the hydraulic cylinder has at least three preset extension lengths.

[0016] Compared with the prior art, this application includes at least one of the following beneficial technical effects:

[0017] This invention utilizes a combination of components including branch pipes, multiple sets of valves, sampling pipes, detection mechanisms, and control mechanisms. Firstly, a first, second, and third valve are added to the connecting pipe. These valves are closed during acid production system shutdowns for maintenance, achieving independent system isolation and preventing backflow of flue gas. Secondly, a bypass flue is formed through the branch pipes. When the denitrification system is under maintenance or the nitrogen oxide emissions from the tail gas meet standards, the second valve is closed and the third valve is opened, allowing the compliant flue gas to be directly discharged without needing to activate the denitrification equipment, avoiding complete production line shutdowns, and reducing energy consumption. This approach completely solves the problems of flue gas backflow, boiler shutdowns during maintenance, and high energy consumption, making the tail gas desulfurization and denitrification system more stable, more flexible in adjustment, and with fully controllable environmental emissions. Attached Figure Description

[0018] Figure 1 This is a process flow diagram for the modification of the tail gas treatment system of the smelting furnace.

[0019] Figure 2 This is a process flow diagram for the modified tail gas treatment system of the smelting furnace.

[0020] Figure 3 This is a schematic diagram of the structure of the first connecting pipe;

[0021] Figure 4 for Figure 3 First-state cross-sectional view;

[0022] Figure 5 for Figure 4 Enlarged view of point A in the middle;

[0023] Figure 6 for Figure 3 The second-state cross-sectional view;

[0024] Figure 7 for Figure 6 Enlarged diagram of point B in the middle.

[0025] Reference numerals: 1. Sulfuric acid tail gas electrostatic precipitator; 2. Fume furnace tail gas electrostatic precipitator; 3. SCR denitrification system; 4. Large chimney; 5. First connecting pipe; 51. Sampling pipe; 52. Hydraulic cylinder; 53. First controller; 54. Second controller; 55. Insertion-type pipeline gas detector; 56. Temperature sensor; 57. Water-cooled coil; 58. Connecting rod; 59. Sealing plate; 6. Second connecting pipe; 7. Third connecting pipe; 8. Branch pipe; 9. First valve; 10. Second valve; 11. Third valve. Detailed Implementation

[0026] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0027] The components of the embodiments of the invention described and shown in the accompanying drawings can typically be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0028] 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.

[0029] Example: Figures 1 to 7As shown, the smelting furnace exhaust gas treatment system proposed in this invention includes a fume extraction furnace tail gas electrostatic precipitator 2 and a sulfuric acid tail gas electrostatic precipitator 1 connected to an SCR denitrification system 3 via a first connecting pipe 5 and a second connecting pipe 6. The SCR denitrification system 3 also includes a large chimney 4 connected via a third connecting pipe 7. A branch pipe 8 is installed between the third connecting pipe 7 and the first connecting pipe 5, connecting the first connecting pipe 5 and the third connecting pipe 7 to form a bypass flue, enabling direct discharge of compliant flue gas. A third valve 11 is installed on the branch pipe 8, controlled by a first controller 53, to achieve automatic bypass discharge of compliant flue gas. A second valve 10 is installed on the first connecting pipe 5, controlling the flow of fume extraction furnace exhaust gas into the SCR denitrification system 3. A first valve 9 is installed on the second connecting pipe 6, controlling the flow of sulfuric acid process exhaust gas, achieving independent system isolation. A sampling tube 51 is fixedly connected to the outer wall of the first connecting pipe 5. The sampling tube 51 provides a sampling and protection chamber for flue gas detection. The first connecting pipe 5 is used to supply nitrogen oxide flue gas, and the sampling tube 51 is equipped with a detection mechanism corresponding to the nitrogen oxide concentration.

[0030] Among them, such as Figures 3 to 5 As shown, the detection mechanism includes an insertion-type pipeline gas detector 55 installed on the sampling tube 51. The insertion-type pipeline gas detector 55 is an industrial-grade device specifically designed for online monitoring of gas concentrations within pipelines. It achieves real-time, continuous measurement of gas composition or concentration by directly inserting a sensor probe into the pipeline. The insertion-type pipeline gas detector 55 is used to detect the concentration of nitrogen oxides in the exhaust gas within the first connecting pipe 5 in real time and transmits the signal. A first controller 53 is provided on the outer wall of the sampling tube 51. The output of the first controller 53 is electrically connected to the third valve 11, and the input of the first controller 53 is electrically connected to the insertion-type pipeline gas detector 55.

[0031] Secondly, such as Figures 3 to 7 As shown, the detection mechanism also includes a hydraulic cylinder 52 fixedly connected to the end of the sampling tube 51 away from the first connecting tube 5. The hydraulic cylinder 52 receives instructions from the second controller 54 to drive the sealing plate 59 to slide, thereby controlling the opening and closing of the sampling chamber. The piston rod of the hydraulic cylinder 52 moves through the sampling tube 51. A pair of sealing plates 59 are slidably provided inside the sampling tube 51. The sealing plates 59 are interference-fitted with the inner wall of the sampling tube 51 to ensure sealing. The sealing plates 59 isolate high-temperature flue gas, protect the insertion-type pipeline gas detector 55, and maintain the chamber seal. A connecting rod 58 is fixedly connected to the middle of the sealing plate 59. One of the sealing plates 59 is fixedly connected to the piston rod of the hydraulic cylinder 52. A temperature measuring mechanism is also provided on the sampling tube 51. Several exhaust micro-holes are opened at the end of the sampling tube 51 away from the first connecting tube 5. The exhaust micro-holes maintain the air pressure balance in the chamber on the side of the sealing plate 59 away from the first connecting tube 5 that is close to the hydraulic cylinder 52.

[0032] In addition, such as Figures 3 to 7 As shown, the temperature measuring mechanism includes a temperature sensor 56 mounted on the sampling tube 51. The temperature sensor 56 is a device that converts a physical quantity of temperature into a measurable electrical signal (such as voltage or resistance). The temperature sensor 56 is used to monitor the flue gas temperature inside the sampling tube 51 in real time and feeds the temperature signal back to the second controller 54. The outer wall of the sampling tube 51 is also equipped with a second controller 54. The output terminal of the second controller 54 is electrically connected to the hydraulic cylinder 52, and the input terminal of the second controller 54 is electrically connected to the temperature sensor 56.

[0033] It is worth noting that, such as Figures 3 to 7 As shown, a water-cooled coil 57 is fitted onto the outer wall of the sampling tube 51. The water-cooled coil 57 is a heat exchange device that uses flowing cold water as a refrigerant to exchange heat with air (or liquid) through the metal tube wall, thereby removing heat and achieving cooling. A pair of sealing plates 59 are correspondingly arranged in the water-cooled coil 57 and the sampling tube 51. The sealing plates 59 are symmetrically arranged with the connecting rod 58 as the center. One of the sealing plates 59 is extended into the first connecting tube 5 by the drive of the hydraulic cylinder 52, and the other sealing plate 59 is located in the sampling tube 51 by the drive of the hydraulic cylinder 52.

[0034] Furthermore, through real-time monitoring, automatic control, and high-temperature protection working in tandem, accurate detection and safe, stable operation of nitrogen oxides in exhaust gas are achieved. A sampling tube 51 is fixed to the outer wall of the first connecting pipe 5, and an insertion-type pipeline gas detector 55 and a temperature sensor 56 are installed on the tube. The insertion-type pipeline gas detector 55 collects nitrogen oxide concentration data in real time and transmits it to the first controller 53, which automatically controls the opening and closing of the third valve 11. Compliant flue gas can be directly discharged via a bypass without denitrification, effectively reducing energy consumption and improving the level of intelligent emission control. The temperature sensor 56 monitors the flue gas temperature and feeds it back to the second controller 54, which controls the hydraulic cylinder 52 to drive the sealing plate 59 to dynamically isolate the high-temperature flue gas. The water-cooled coil 57 on the outer wall of the sampling tube 51 continuously cools the gas, providing double protection to prevent high-temperature damage to the insertion-type pipeline gas detector 55, extending equipment life, reducing maintenance costs, ensuring accurate and stable detection, and guaranteeing safe and efficient system operation and stable compliance with emission standards.

[0035] It is worth mentioning that the hydraulic cylinder 52 has at least three preset extension lengths, which are used for sampling, cooling and detection, respectively.

[0036] In this embodiment, when using the smelting furnace tail gas treatment system, the sulfuric acid tail gas electrostatic precipitator 1 is connected to the SCR denitrification system 3 through the second connecting pipe 6 and the first connecting pipe 5, and the fuming furnace tail gas electrostatic precipitator 2 is directly connected to the SCR denitrification system 3 through the first connecting pipe 5. The SCR denitrification system 3 is then connected to the large chimney 4 through the third connecting pipe 7. The branch pipe 8 is connected between the first connecting pipe 5 and the third connecting pipe 7 to realize the two-way interconnection. The second valve 10 is installed on the first connecting pipe 5, the first valve 9 is installed on the second connecting pipe 6, and the third valve 11 is installed on the branch pipe 8.

[0037] When the system is operating normally and requires denitrification treatment of the exhaust gas, open the first valve 9 and the second valve 10, and close the third valve 11. The exhaust gas generated by the electrostatic precipitator 2 at the tail end of the fuming furnace enters the SCR denitrification system 3 through the first connecting pipe 5 and the second valve 10. The exhaust gas generated by the electrostatic precipitator 1 at the tail end of the sulfuric acid furnace enters the SCR denitrification system 3 through the second connecting pipe 6, the first valve 9, and the first connecting pipe 5. The two exhaust gases undergo denitrification and purification in the SCR denitrification system 3, and after meeting the standards, they are transported to the large chimney 4 through the third connecting pipe 7 and finally discharged to the outside.

[0038] When the SCR denitrification system 3 requires maintenance, all valves are shut off to effectively isolate the acid production system from the flue gas desulfurization system. Closing the valves during shutdown prevents backflow of flue gas. When the nitrogen oxide concentration in the exhaust gas from the electrostatic precipitator 2 at the tail end of the flue gas furnace has reached the environmental emission standards and denitrification is not required, the second valve 10 is closed and the third valve 11 is opened. The exhaust gas generated by the electrostatic precipitator 2 at the tail end of the flue gas furnace flows directly into the third connecting pipe 7 through the first connecting pipe 5, the branch pipe 8, and the third valve 11, and is then discharged through the large chimney 4. There is no need to start the SCR denitrification system 3, avoiding a complete shutdown and reducing operating energy consumption.

[0039] A sampling tube 51 is fixedly installed on the outer wall of the first connecting pipe 5. An insertion-type pipeline gas detector 55 and a temperature sensor 56 are installed on the sampling tube 51. The insertion-type pipeline gas detector 55 detects the nitrogen oxide concentration of the exhaust gas in the first connecting pipe 5 in real time and transmits the concentration signal to the first controller 53. The first controller 53 automatically controls the opening and closing of the third valve 11 according to the preset concentration threshold, so as to realize the automatic bypass discharge of the compliant exhaust gas.

[0040] Temperature sensor 56 monitors the flue gas temperature in sampling tube 51 in real time and feeds the temperature signal back to second controller 54. Second controller 54 controls the start and stop of hydraulic cylinder 52 based on the temperature data. The piston rod of hydraulic cylinder 52 drives connecting rod 58 to move, and connecting rod 58 drives a pair of symmetrically arranged sealing plates 59 to slide inside sampling tube 51. Under high temperature conditions, one sealing plate 59 extends into the first connecting tube 5, while the other sealing plate 59 remains in sampling tube 51 to maintain the seal of the detection chamber. Subsequently, hydraulic cylinder 52 retracts, driving the pair of sealing plates 59 back into sampling tube 51. At this time, the flue gas in the first connecting tube 5 enters sampling tube 51, presenting a... Figure 5 As shown, avoid direct contact between high-temperature flue gas and the insertion-type pipeline gas detector 55.

[0041] A water-cooling coil 57 is fitted onto the outer wall of the sampling tube 51. During continuous operation, cooling water is continuously circulated to cool the sampling tube 51, effectively resisting the heat radiation of the high-temperature flue gas and protecting the insertion-type pipeline gas detector 55 on the sampling tube 51. After cooling, the flue gas is restarted by the hydraulic cylinder 52, driving a pair of sealing plates 59 to push the cooled flue gas inside the sampling tube 51 to the detection position of the insertion-type pipeline gas detector 55. Figure 7 As shown, this avoids damage to the insertion-type pipeline gas detector 55 due to excessively high flue gas temperature.

[0042] The preferred embodiments of the present invention described above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A system for treating exhaust gas from a smelting furnace, comprising an electrostatic precipitator (2) for the tail gas of a fuming furnace and an electrostatic precipitator (1) for the tail gas of a sulfuric acid furnace, which are connected to an SCR denitrification system (3) via a first connecting pipe (5) and a second connecting pipe (6), wherein the SCR denitrification system (3) is further provided with a large chimney (4) connected via a third connecting pipe (7), characterized in that, Also includes: A branch pipe (8) is installed in the middle of the third connecting pipe (7) and the first connecting pipe (5) to connect the third connecting pipe (7) and the first connecting pipe (5). A third valve (11) is installed on the branch pipe (8), a second valve (10) is installed on the first connecting pipe (5), and a first valve (9) is installed on the second connecting pipe (6). The sampling tube (51) is fixedly connected to the outer wall of the first connecting tube (5). The first connecting tube (5) is used to supply nitrogen oxide flue gas. The sampling tube (51) is equipped with a detection mechanism corresponding to the nitrogen oxide concentration.

2. The smelting furnace exhaust gas treatment system according to claim 1, characterized in that, The detection mechanism includes an insertion-type pipeline gas detector (55) installed on a sampling tube (51). The outer wall of the sampling tube (51) is provided with a first controller (53). The output end of the first controller (53) is electrically connected to a third valve (11), and the input end of the first controller (53) is electrically connected to the insertion-type pipeline gas detector (55).

3. The smelting furnace exhaust gas treatment system according to claim 1, characterized in that, The detection mechanism also includes a hydraulic cylinder (52) fixedly connected to the end of the sampling tube (51) away from the first connecting tube (5). The piston rod of the hydraulic cylinder (52) moves through the sampling tube (51). A pair of sealing plates (59) are slidably provided inside the sampling tube (51). A connecting rod (58) is fixedly connected to the middle of the sealing plate (59). One of the sealing plates (59) is fixedly connected to the piston rod of the hydraulic cylinder (52). The sampling tube (51) is also provided with a temperature measuring mechanism.

4. The smelting furnace exhaust gas treatment system according to claim 3, characterized in that, The temperature measuring mechanism includes a temperature sensor (56) installed on the sampling tube (51). The outer wall of the sampling tube (51) is also provided with a second controller (54). The output end of the second controller (54) is electrically connected to the hydraulic cylinder (52), and the input end of the second controller (54) is electrically connected to the temperature sensor (56).

5. The smelting furnace exhaust gas treatment system according to claim 3, characterized in that, The outer wall of the sampling tube (51) is fitted with a water-cooling coil (57), and the water-cooling coil (57) is correspondingly set with a pair of sealing plugs (59) inside the sampling tube (51).

6. The smelting furnace exhaust gas treatment system according to claim 3, characterized in that, The pair of sealing plates (59) are arranged symmetrically with respect to the connecting rod (58).

7. The smelting furnace exhaust gas treatment system according to claim 3, characterized in that, One of the sealing plates (59) is extended into the first connecting pipe (5) by the drive of the hydraulic cylinder (52), and the other sealing plate (59) is located in the sampling pipe (51) by the drive of the hydraulic cylinder (52).

8. The smelting furnace exhaust gas treatment system according to claim 3, characterized in that, The sampling tube (51) has several exhaust micro-holes at the end away from the first connecting tube (5).

9. The smelting furnace exhaust gas treatment system according to claim 3, characterized in that, The sealing plate (59) is interference-fitted with the inner wall of the sampling tube (51).

10. The smelting furnace exhaust gas treatment system according to claim 3, characterized in that, The hydraulic cylinder (52) has at least three preset extension lengths.

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