Fume hood device and system for reducing SO2 content in exhaust gas from belt roaster

Abstract

This invention discloses a fume hood device and system for reducing the SO2 content in the exhaust gas of a belt roaster during the drying process. The belt roaster includes a drying section and an extraction section. The drying section includes a drying fume hood and a drying air box connected vertically to the trolley. The extraction section includes an extraction fume hood and an extraction air box connected vertically to the trolley. The fume hood device includes a fume hood partition and an air curtain duct. The fume hood partition is vertically installed inside the extraction fume hood, close to the drying fume hood. Except for the bottom edge, the partition is connected to the inner edge of the extraction fume hood. The bottom edge of the partition is located close to the trolley. The air curtain duct is arranged outside the drying air box and includes a first end and a second end. The first end is connected to the drying air box, and the second end is connected to the extraction fume hood and located at the lower end of the fume hood partition. The outlet of the second end faces downward. During operation, an air-blocking air curtain is formed between the fume hood partition and the trolley through the air curtain duct.

Description

Technical Field

[0001] This invention relates to the field of pellet roasting technology in belt roasters, and particularly to a fume hood device and system for reducing the SO2 content in the exhaust gas from belt roasters. Background Technology

[0002] Currently, in domestically operational belt-type calciner pelletizing production lines, the exhaust gas systems for the drying process only have dust removal facilities, lacking desulfurization facilities. Due to the cross-contamination of exhaust gas from the drying hood, the SO2 content in the exhaust gas is consistently ≥80 mg / Nm³. 3 The plant failed to meet emission standards and was ordered by environmental protection authorities to add desulfurization facilities or cease production. This situation increased the investment, construction, and operating costs for the pellet plant. Summary of the Invention

[0003] This application provides a fume hood device and system for reducing the SO2 content in the dry exhaust gas of a belt calciner, which solves the technical problem of SO2 content in the dry exhaust gas exceeding emission standards in the pelletizing process production line of a belt calciner.

[0004] This application provides a fume hood device for reducing the SO2 content in the exhaust gas of a belt roaster. The belt roaster includes a drying section and an extraction section. The drying section includes a drying fume hood and a drying air box connected vertically to the trolley. The extraction section includes an extraction fume hood and an extraction air box connected vertically to the trolley. The fume hood device includes a fume hood partition and an air curtain duct. The fume hood partition is vertically installed inside the extraction fume hood and is close to the drying fume hood. Except for the bottom edge, the fume hood partition is connected to the inner edge of the extraction fume hood. The bottom edge of the fume hood partition is located close to the trolley. The air curtain duct is arranged outside the drying air box and includes a first end and a second end. The first end is connected to the drying air box, and the second end is connected to the extraction fume hood and located at the lower end of the fume hood partition. The outlet of the second end faces downward. In operation, an air-blocking air curtain is formed between the fume hood partition and the trolley through the air curtain duct.

[0005] In some embodiments, the fume hood device further includes: a first partition seal, installed on a first crossbeam at the junction of the blower box and the desiccant box, for floating seal of the gap between the first crossbeam and the worktable; a blower box partition and a second partition seal, wherein the blower box partition is vertically installed inside the desiccant box, the blower box partition is located directly below the fume hood partition, the blower box partition is connected to the inner edge of the desiccant box except for the top side, a second crossbeam is installed on the top side of the blower box partition, and the second partition seal is installed on the second crossbeam for floating seal of the gap between the second crossbeam and the worktable.

[0006] In some implementations, both the fume hood baffle and the bellows baffle are made of R345 steel.

[0007] In some embodiments, the fume hood device further includes: an air-cooled beam, the inlet of which is ambient cold air, the outlet of which is connected to the exhaust fan box, and the air-cooled beam is equipped with a regulating valve. The air-cooled beam is used to cool the partition wall between the blower section and the exhaust section.

[0008] A fume hood system for reducing SO2 content in the exhaust gas from a belt roaster includes a drying fume hood, a drying air box, an extraction fume hood, an extraction air box, and the aforementioned fume hood devices. A trolley is installed between the drying fume hood and the drying air box, and between the extraction fume hood and the extraction air box. The drying fume hood is connected to the drying exhaust fan, the drying air box is connected to the drying blower, the extraction fume hood is connected to the reheat fan, and the extraction air box is connected to the main induced draft fan.

[0009] In some implementations, compensators are installed at the inlet and outlet of the blower, the dryer blower, the regenerating blower, and the main induced draft fan to prevent the connecting pipes from being damaged by thermal expansion.

[0010] In some implementations, a bag filter is installed in the connecting pipe between the drying fume hood and the drying exhaust fan, and an electrostatic precipitator is installed in the connecting pipe between the drying air box and the main induced draft fan.

[0011] In some implementations, a first high-temperature butterfly valve is installed on the outlet pipe of the drying blower, and a second high-temperature butterfly valve is installed on the outlet pipe of the regenerating blower.

[0012] In some embodiments, the outlet of the blower box is equipped with a first double-layer ash discharge valve, through which dust and particulate matter are discharged onto the belt conveyor; the outlet of the desiccant box is equipped with a second double-layer ash discharge valve, through which dust and particulate matter are discharged onto the belt conveyor.

[0013] In some implementations, when the belt roaster is in operation, the internal pressure of the drying air box is 3.0 to 5.5 kPa, the internal pressure of the drying fume hood is -0.01 to -0.1 kPa, and the internal pressure of the drying air box is -1.5 to -4.0 kPa.

[0014] The beneficial effects of this application are as follows: It provides a fume hood device for reducing the SO2 content in the exhaust gas of a belt roaster, including a fume hood partition and an air curtain duct. The fume hood partition is vertically installed inside the drying fume hood, close to the drying fume hood. Except for the bottom edge, the partition is connected to the inner edge of the drying fume hood. The bottom edge of the partition is located close to the trolley. The air curtain duct is arranged outside the drying air box, and includes a first end and a second end. The first end communicates with the drying air box, and the second end communicates with and is located in the drying fume hood. At the lower end of the fume hood partition, the second end of the air outlet faces downwards. Using the fume hood device of this application, the pressure difference between the positive pressure inside the blower box and the negative pressure inside the fume hood during operation causes some of the hot air from the blower box to enter the fume hood along the air curtain duct. The hot air then exits downwards from the lower end of the fume hood partition from the second end of the air curtain duct, thus forming an air-blocking curtain between the fume hood partition and the trolley. Combined with the fume hood partition vertically installed inside the fume hood, this prevents the SO2 content inside the fume hood from exceeding 80 mg / Nm³. 3 The flue gas enters the drying hood, and the SO2 content of the hot air in the drying box is ≤20mg / Nm³. 3 This invention enables the SO2 content of the exhaust gas from the drying process to meet emission standards. The fume hood device of this application has the advantages of simple manufacturing, low cost and convenient modification. It can quickly modify the drying section and extraction section of the existing belt calciner pellet production line to make the exhaust gas from the drying process meet emission standards, reduce plant costs, maintain the continued operation of the belt calciner and ensure normal production. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention.

[0016] Figure 1 A schematic diagram of the overall structure of the fume hood device and system for reducing SO2 content in the exhaust gas of a belt roaster provided in this application;

[0017] Figure 2 for Figure 1 A schematic diagram of the gas path involved in the middle blower fume hood and the blower box;

[0018] Figure 3 for Figure 1 A schematic diagram of the gas path involved in the extraction fume hood and extraction air box.

[0019] Attached diagram labels: 1-Drying exhaust fan, 2-Bag filter, 3-Regulating valve, 4-Air-cooled beam, 5-Drying fume hood, 6-Air curtain duct, 7-Trolley, 8-Drying air box, 91-First double-layer ash discharge valve, 92-Second double-layer ash discharge valve, 10-Belt conveyor, 111-First high-temperature butterfly valve, 112-Second high-temperature butterfly valve, 12-Drying blower, 13-Regenerating fan, 14-Drying fume hood, 15-Fume hood partition, 161-First partition seal, 162-Second partition seal, 17-Air box partition, 18-Drying air box, 19-Electrostatic precipitator, 20-Main induced draft fan. Detailed Implementation

[0020] Example 1

[0021] A fume hood device for reducing SO2 content in the exhaust gas from a belt roaster is disclosed. For more information on belt roasters, please refer to [link to relevant documentation]. Figure 1 The belt roasting machine includes a trolley 7, which includes a drying section and a desiccation section arranged sequentially in the process.

[0022] The drying section includes a drying air box 8 located below the trolley 7 and a drying fume hood 5 located above the trolley 7. The drying air box 8 is connected to the drying fume hood 5, the drying fume hood 5 is connected to the drying exhaust fan 1, and the drying air box 8 is connected to the drying blower 12. Figure 2 A schematic diagram of the relevant gas path is shown. Hot air from the cooling section fume hood enters the drying air box 8 through the drying blower 12, acts on the pellets on the passing trolley 7, and then goes to the exhaust chimney through the drying exhaust fan 1 via the drying fume hood 5.

[0023] The drying section includes a drying air box 18 located below the trolley 7 and a drying fume hood 14 located above the trolley 7. The drying air box 18 and the drying fume hood 14 are connected. Figure 1 As shown, the exhaust fan 18 is connected to the forced-dry fan 8, and a partition wall is installed at the connection point, which serves as the partition wall between the forced-dry section and the exhaust fan section. Figure 1 As shown, the exhaust hood 14 is connected to the regenerating fan 13, and the exhaust air box 18 is connected to the main induced draft fan 20. Figure 3 A schematic diagram of the relevant gas path is shown. The flue gas from the roasting section air box enters the drying hood 14 through the reheating fan 13. After acting on the pellets on the passing trolley 7, it goes to the flue gas treatment system through the drying air box 18 and then to the main induced draft fan 20.

[0024] This application discloses a fume hood device for reducing the SO2 content in the exhaust gas of a belt roaster. Please refer to [reference needed]. Figure 1The fume hood device includes a fume hood baffle 15 and an air curtain duct 6. The fume hood baffle 15 is installed inside the desiccation fume hood 14, and is vertically mounted above the trolley 7. The fume hood baffle 15 is spaced apart from the trolley 7 to avoid obstructing the movement of the pellets on the trolley 7. The fume hood baffle 15 is relatively close to the desiccation fume hood 5 because its purpose is to prevent gas from entering the desiccation fume hood 5. Its proximity to the desiccation fume hood 5 provides a better blocking effect and maintains the normal operation of the desiccation fume hood 14.

[0025] Please refer to Figure 1 The fume hood partition 15 is designed to be connected to the inner edge of the desiccant fume hood 14 except for the bottom edge, and the bottom edge of the fume hood partition 15 is located close to the trolley 7. The main body of the air curtain duct 6 is arranged outside the blower box 8, and both ends of the air curtain duct 6 are connected to the blower box 8 and the desiccant fume hood 14, respectively.

[0026] In detail, the two opposite ends of the air curtain duct 6 are the first end and the second end (not shown in the figure). The first end is connected to the drying air box 8, and the second end is connected to the extraction fume hood 14. The second end is located at the lower end of the fume hood partition 15, and the air outlet of the second end faces downward. When in operation, the drying air box 8 is under positive pressure, with an internal pressure of 3.0 to 5.5 kPa. The extraction fume hood 14 is under negative pressure, with an internal pressure of -0.01 to -0.1 kPa. This creates a pressure difference between the two opposite ends of the air curtain duct 6, causing some of the hot air in the drying air box 8 to enter the extraction fume hood 14 along the air curtain duct 6 and exit downward from the lower end of the fume hood partition 15 from the second end of the air curtain duct 6. This forms an air-blocking air curtain between the fume hood partition 15 and the trolley 7.

[0027] The SO2 content of the smoke inside the fume hood 14 is ≥80mg / Nm³. 3 The SO2 content of the hot air inside the blower box 8 is ≤20mg / Nm³. 3 The air curtain formed by the air curtain duct 6 during operation, together with the baffle plate 15 installed vertically in the exhaust hood 14, prevents the flue gas in the exhaust hood 14 from entering the drying hood 5. Overall, it works in conjunction with the partition wall and other structures originally set in the belt roaster, so that the SO2 content of the drying exhaust gas meets the emission standards.

[0028] The use of this fume hood device has the advantages of simple manufacturing, low cost and convenient modification. It can quickly modify the drying section and extraction section of the existing belt calciner pellet production line, so that the exhaust gas from the drying section meets the emission standards, reduces the cost of the plant, maintains the continued operation of the belt calciner and ensures normal production.

[0029] Please refer to Figure 1It also involves the hot air blocking setting of the exhaust fan 18. In some embodiments, the fume hood device also includes a first partition seal 161 and a second partition seal 162, the second partition seal 162 cooperating with the fan partition 17.

[0030] Specifically, below the trolley 7, the belt roaster has a first crossbeam at the junction of the drying air box 8 and the exhaust air box 18. Figure 1 The triangle shape indicated by 161 is shown in the middle. The first partition seal 161 is installed on the first crossbeam at the junction of the blower air box 8 and the desiccant air box 18. By setting the first partition seal 161, the gap between the first crossbeam and the trolley 7 is floated and sealed. The floating seal design can adapt to the passage of the trolley 7.

[0031] A baffle plate 17 is installed on the exhaust fan 18. The baffle plate 17 is vertically oriented and positioned directly below the fume hood baffle plate 15. Except for its top side, the baffle plate 17 is connected to the inner edge of the exhaust fan 18. A second crossbeam is installed on the top side of the baffle plate 17. Figure 1 The triangle shape indicated by 162 is shown in the middle. There is a gap between the second crossbeam and the trolley 7. The gap between the second crossbeam and the trolley 7 is floated and sealed by the second partition seal 162 installed on the second crossbeam. The floating seal design can adapt to the passage of the trolley 7.

[0032] A dummy air box is formed by setting an air box partition 17 inside the exhaust air box 18. The two ends of the dummy air box are double-sealed by a first partition seal 161 and a second partition seal 162 to prevent the flue gas inside the exhaust air box 18 from entering the blower air box 8.

[0033] This fume hood device, applied in a belt roaster, prevents flue gas from the extraction fume hood 14 from entering the drying fume hood 5 by setting up fume hood baffles 15 and air curtain ducts 6. A dummy air box is installed between the drying and extraction sections in the extraction air box 18, employing double-partition sealing to prevent flue gas from the extraction air box 18 from entering the drying air box 8. Overall, this ensures an SO2 content ≥80mg / Nm³. 3 The flue gas does not enter the drying hood 5, ensuring that the SO2 content of the flue gas inside the drying hood 5 is ≤20mg / Nm³. 3 .

[0034] Regarding the fume hood baffle 15, it is made of R345 steel to reduce thermal expansion and burn-off. Similarly, the wind box baffle 17 is also made of R345 steel to reduce thermal expansion and burn-off.

[0035] To maintain the normal operation of the partition wall between the drying section and the extraction section, please refer to... Figure 1In some embodiments, the fume hood device further includes a cooling beam 4, which has an inlet and an outlet. The inlet of the cooling beam 4 is ambient cold air, and the outlet of the cooling beam 4 is connected to the extraction air box 18. The cooling beam 4 is equipped with a regulating valve 3. The internal pressure of the extraction air box 18 is negative, specifically between -1.5 and -4.0 kPa. The pressure difference allows cold air to automatically enter the cooling beam 4 and then into the extraction air box 18 to cool the partition wall between the blower section and the extraction section.

[0036] Example 2

[0037] Example 1 discloses a fume hood device for reducing the SO2 content in the exhaust gas of a belt roaster. This application also protects a fume hood system for reducing the SO2 content in the exhaust gas of a belt roaster. The fume hood system includes a drying fume hood 5, a drying air box 8, an extraction fume hood 14, an extraction air box 18, and the fume hood device in Example 1, with the fume hood device installed accordingly.

[0038] like Figure 1 As shown, the trolley 7 is installed between the drying fume hood 5 and the drying air box 8, and between the extraction fume hood 14 and the extraction air box 18. The drying fume hood 5 is connected to the drying exhaust fan 1, the drying air box 8 is connected to the drying blower 12, the extraction fume hood 14 is connected to the regenerating fan 13, and the extraction air box 18 is connected to the main induced draft fan 20. This configuration can be combined with... Figure 2 and Figure 3 Understand gas pathways.

[0039] In some implementations, compensators are installed at the inlet and outlet of the blower 1, blower 12, regenerating fan 13 and main induced draft fan 20 to prevent the connecting pipes from being damaged by thermal expansion.

[0040] In some implementation methods, please refer to Figure 1 and Figure 2 A bag filter 2 is installed in the connecting pipe between the blower hood 5 and the blower exhaust fan 1. After the blower exhaust gas passes the dust removal standard, it is discharged into the atmosphere through the chimney.

[0041] In some implementation methods, please refer to Figure 1 and Figure 3 An electrostatic precipitator 19 is installed in the connecting pipe between the exhaust fan 18 and the main exhaust fan 20. After the main exhaust flue gas passes through the dust removal and meets the standards, it goes to the flue gas treatment system.

[0042] In some implementation methods, please refer to Figure 1 and Figure 2 A first high-temperature butterfly valve 111 is installed on the outlet pipe of the blower 12 to regulate the air volume and pressure entering the blower box 8.

[0043] In some implementation methods, please refer to Figure 1 and Figure 3 A second high-temperature butterfly valve 112 is installed on the outlet pipe of the regenerating fan 13 to regulate the air volume and hood pressure entering the exhaust hood 14.

[0044] In some implementation methods, please refer to Figure 1 and Figure 2 The outlet of the blower box 8 is equipped with a first double-layer ash discharge valve 91. Dust and particulate matter are discharged onto the belt conveyor 10 through the first double-sided ash discharge valve and then transported out of the system. Figure 1 The direction of operation of belt conveyor 10 is indicated by an arrow at belt conveyor 10.

[0045] In some implementation methods, please refer to Figure 1 and Figure 3 The outlet of the exhaust fan 18 is equipped with a second double-layer ash discharge valve 92. Dust and particulate matter are discharged onto the belt conveyor 10 through the second double-layer ash discharge valve 92 and then transported out of the system.

[0046] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0047] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A hood system for reducing the SO2 content of the exhaust gases from a drum of a belt roaster, characterised in that, The device comprises a drum drying fume hood, a drum drying air box, a drawing drying fume hood, a drawing drying air box, and a fume hood device for reducing the SO2 content of drum drying exhaust gas of a belt-type roaster, a trolley is arranged between the drum drying fume hood and the drum drying air box and between the drawing drying fume hood and the drawing drying air box, the drum drying fume hood is connected with a drum drying exhaust fan, the drum drying air box is connected with a drum drying air fan, the drawing drying fume hood is connected with a regenerative air fan, and the drawing drying air box is connected with a main induced draft fan; The belt-type roaster comprises a drum drying section and a drawing drying section, the drum drying section comprises a drum drying fume hood and a drum drying air box which are connected in sequence on a trolley, the drawing drying section comprises a drawing drying fume hood and a drawing drying air box which are connected in sequence on a trolley, and the fume hood device comprises: A fume hood partition plate is vertically arranged in the drawing drying fume hood, the fume hood partition plate is close to the drum drying fume hood, the fume hood partition plate is connected with the inner edge of the drawing drying fume hood except the bottom side edge, and the bottom side of the fume hood partition plate is close to the trolley; An air curtain pipe is arranged outside the drum drying air box, the air curtain pipe comprises opposite first and second ends, the first end is connected with the drum drying air box, the second end is connected with the drawing drying fume hood and is located at the lower end of the fume hood partition plate, the air outlet of the second end faces downward, and in a running state, an air resistance wind curtain is formed between the fume hood partition plate and the trolley through the air curtain pipe; A first partition sealing is arranged on a first cross beam at the joint of the drum drying air box and the drawing drying air box, and is used for floatingly sealing the gap between the first cross beam and the trolley; and An air box partition plate and a second partition sealing are arranged, the air box partition plate is vertically arranged in the drawing drying air box, the air box partition plate is arranged directly below the fume hood partition plate, the air box partition plate is connected with the inner edge of the drawing drying air box except the top side, the top side of the air box partition plate is provided with a second cross beam, and the second partition sealing is arranged on the second cross beam and is used for floatingly sealing the gap between the second cross beam and the trolley, wherein the first partition sealing, the second partition sealing, the air box partition plate, the wall of the drawing drying air box and the trolley form a false air box; Compensators are arranged at the inlets and outlets of the drum drying exhaust fan, the drum drying air fan, the regenerative air fan and the main induced draft fan, so as to prevent the connecting pipelines from being damaged due to thermal expansion. A bag-type dust collector is arranged in the connecting pipeline between the drum drying fume hood and the drum drying exhaust fan, and an electric dust collector is arranged in the connecting pipeline between the drawing drying air box and the main induced draft fan.

2. The hood system of claim 1, wherein, The materials of the fume hood partition plate and the air box partition plate comprise R345 steel.

3. The hood system according to any one of claims 1 or 2, wherein The fume hood device further comprises: An air cooling beam, the inlet of the air cooling beam is connected with ambient cold air, the outlet of the air cooling beam is connected with the drawing drying air box, a regulating valve is arranged on the air cooling beam, and the air cooling beam is used for cooling the partition wall between the drum drying section and the drawing drying section.

4. The hood system of claim 1, wherein, A first high-temperature butterfly valve is arranged on the outlet pipeline of the drum drying air fan, and a second high-temperature butterfly valve is arranged on the outlet pipeline of the regenerative air fan.

5. The hood system of claim 1, wherein, A first double-layer dust discharging valve is arranged at the outlet of the drum drying air box, and dust and particulate matter are discharged onto a belt conveyor through the first double-layer dust discharging valve. A second double-layer dust discharging valve is arranged at the outlet of the drawing drying air box, and dust and particulate matter are discharged onto a belt conveyor through the second double-layer dust discharging valve.

6. The hood system of any one of claims 1, 4, 5, wherein, In the running state of the belt roaster, the inner pressure of the drum dry wind box is 3.0-5.5 kPa, the inner pressure of the dry smoke hood is -0.01--0.1 kPa, and the inner pressure of the dry wind box is -1.5--4.0 kPa.

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