A multi-stage denitration system for smelting flue gas to prepare analytically pure sulfuric acid

Abstract

The present application relates to smelting flue gas preparation of analytical pure sulfuric acid technical field, disclose a kind of smelting flue gas multistage denitration preparation of analytical pure sulfuric acid system, including primary fine denitration system and secondary purification system, the primary fine denitration system includes ozone generator, drying tower, wherein the ozone generator is arranged at the flue of drying tower inlet smoke port, the secondary purification system includes precision filter and nicotinic acid washing tower, most of NO in flue gas is first oxidized to high-valence nitrogen oxides by ozone, then absorbed by the drying tower circulating acid and denitration, the remaining small amount of NO is catalytically oxidized to high-valence nitrogen oxides by acid preparation conversion process, after secondary filtration and washing purification of precision filter and nicotinic acid washing tower, it enters analytical pure absorption tower, the circulating tank of drying tower and nicotinic acid washing tower is mutually acid, the present application is by " primary fine denitration+two-stage purification " process, the nitrate content in the analytical pure sulfuric acid produced reaches standard.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of smelting flue gas for preparing analytical pure sulfuric acid, and particularly relates to a smelting flue gas multi-stage denitration system for preparing analytical pure sulfuric acid. BACKGROUND

[0002] For the current absorption method for preparing analytical pure process, the NOx content of the flue gas from the smelting furnace (low-blowing furnace, side-blowing furnace, etc. oxygen-rich, high-temperature smelting process) of the non-ferrous smelting industry is relatively high (500-2000 mg / m3), and the subsequent acid-making process, whether it is a two-stage two-absorption process for high-concentration SO2 flue gas acid-making or a one-stage one-absorption process for low-concentration SO2 flue gas acid-making, is divided into two types: gas separation and concentration: ion liquid absorption and desorption + one-stage one-absorption process for preparing analytical pure; without gas separation and concentration: ion liquid system absorption and desorption gas for preparing analytical pure, the prepared analytical pure nitrate (NO3 - ) is over standard (referring to GB / T 625-2007). SUMMARY

[0003] The purpose of the present application is to provide a smelting flue gas multi-stage denitration system for preparing analytical pure sulfuric acid, which can make the nitrate content in the prepared analytical pure sulfuric acid meet the standard by using a “one-stage fine denitration + two-stage purification” process.

[0004] The above technical purpose of the present application is achieved by the following technical scheme: a smelting flue gas multi-stage denitration system for preparing analytical pure sulfuric acid, comprising a one-stage fine denitration system and a two-stage purification system, the one-stage fine denitration system comprising an ozone generator and a drying tower, wherein the ozone generator is arranged at the flue of the flue gas inlet of the drying tower, the two-stage purification system comprising a precision filter and a nicotinic acid washing tower, the one-stage fine denitration system comprising an ozone generator and a drying tower, wherein the ozone generator is arranged at the flue of the flue gas inlet of the drying tower, the two-stage purification system comprising a precision filter and a nicotinic acid washing tower, in the absorption method for preparing analytical pure process after the acid-making conversion section, the converted flue gas is subjected to two-stage purification treatment by using the precision filter, the nicotinic acid washing purification tower and the analytical pure absorption tower process, the liquid tank at the bottom of the drying tower is communicated with the liquid tank below the nicotinic acid washing tower through the first circulation pipe and the second circulation pipe, and the drying tower and the nicotinic acid washing tower are mutually connected.

[0005] By using the above technical scheme, most of the NO in the flue gas is first oxidized to high-valence nitrogen oxides by ozone and then absorbed by the circulating acid of the drying tower to remove nitrogen oxides, and the remaining small amount of NO is further catalytically oxidized to high-valence nitrogen oxides by the acid-making conversion section, and then enters the analytical pure absorption tower after two-stage filtration and washing purification by the precision filter and the nicotinic acid washing tower, and the circulating tanks of the drying tower and the nicotinic acid washing tower are mutually connected.

[0006] The application adopts a new combined process of "one-stage fine denitration + two-stage purification", which can ensure that the product analysis nitrate index is qualified. The one-stage fine denitration process is as follows: the nitrogen monoxide is removed by being oxidized by ozone and then being absorbed by dry concentrated acid. Specifically, an ozone generator is arranged before the entrance of the drying tower of the dry absorption process. The ozone generator must be arranged after the acid-making purification electric demisting and before the entrance of the drying tower. The ozone generator is used to oxidize the NO in the flue gas into high-valence nitrogen oxides, which are then absorbed by the circulating 93% acid in the drying tower. The one-stage fine denitration process can remove more than 90% of the nitrogen oxides, so that the content of the nitrogen oxides in the flue gas entering the acid-making conversion process is reduced to below 50 mg / m3. The two-stage purification process is as follows: the fine filter purification + the nicotinic acid washing purification process. The purpose of the one-stage fine filter purification is to remove the conversion catalyst dust carried by the flue gas. The purpose of the two-stage nicotinic acid washing purification is to remove the small amount of nitrogen monoxide in the flue gas which is not removed by the one-stage fine denitration. The nitrogen monoxide generates high-valence nitrogen oxides in the acid-making conversion process, which can be dissolved in the nicotinic acid to generate nitrosyl sulfuric acid in the nicotinic acid washing tower. Finally, the nitrate content in the product analysis is completely up to the standard by using the above new combined process. In the process, the nicotinic acid is regularly discharged to the drying tower. The concentrated sulfuric acid produced by the drying tower can reach the first-class product of GB / T534-2014, which can be sold externally, and has good economic benefits.

[0007] The application further provides that the mass fraction of the circulating liquid at the bottom of the drying tower is 93% sulfuric acid.

[0008] The application further provides that the mass fraction of the circulating liquid in the nicotinic acid washing tower is 105% sulfuric acid.

[0009] By using the above technical scheme, the first circulating pipe and the second circulating pipe are arranged between the drying tower and the nicotinic acid washing tower. Since the sulfuric acid in the liquid tank of the drying tower is regularly discharged as industrial concentrated sulfuric acid, the circulating liquid in the drying tower is reduced. The concentrated sulfuric acid at the bottom of the nicotinic acid washing tower can supplement the circulating liquid of the drying tower through the first circulating pipe. At the same time, since the concentration of the concentrated sulfuric acid in the nicotinic acid washing tower is further increased in the reaction process, the lower concentration of the concentrated sulfuric acid in the drying tower is transported to the nicotinic acid washing tower through the second circulating pipe to maintain the balance of the volume and concentration of the concentrated sulfuric acid in the drying tower and the nicotinic acid washing tower.

[0010] The application further provides that the inner membrane of the fine filter is coated with a polytetrafluoroethylene coating.

[0011] By adopting the technical scheme, the precise filter device in the application adopts stainless steel 316L material, the filter inner cylinder adopts imported polytetrafluoroethylene film, and special process is prepared to ensure stable operation of the device; the nicotinic acid washing tower device shell adopts stainless steel 316L material, is lined with special acid-resistant ceramic tiles, has good adaptability to the mixed environment of concentrated nitric acid and concentrated sulfuric acid, and is suitable for the working condition of high-temperature concentrated acid circulation spraying and washing.

[0012] Further, the nicotinic acid washing tower comprises a tower body, an inlet and an outlet arranged on the tower body, and the tower body is sequentially provided with a liquid tank, reaction filler, a spraying system and demisting filler from bottom to top, the spraying system comprises a liquid pipe, a three-way pipe, an upper spraying pipe and a lower spraying pipe, the liquid pipe is communicated with the liquid tank below the nicotinic acid washing tower and the three-way pipe, the upper spraying pipe is communicated with the upper part of the three-way pipe, the lower spraying pipe is communicated with the lower part of the three-way pipe, a plurality of spray heads are arranged on the upper spraying pipe and the lower spraying pipe, a distance adjusting mechanism is arranged between the upper spraying pipe and the lower spraying pipe, and the distance adjusting mechanism drives the upper spraying pipe to move close to or away from the lower spraying pipe.

[0013] By adopting the technical scheme, the content of tail gas NOx can be further reduced, and the ammonia nitrogen absorption rate can be improved; when the content of ammonia nitrogen in flue gas is high, the distance between the upper spraying pipe and the lower spraying pipe is increased through the distance adjusting mechanism, the reaction channel of flue gas and spraying liquid sulfuric acid is increased, and the ammonia nitrogen compound in flue gas can fully react with concentrated sulfuric acid.

[0014] Further, the distance adjusting mechanism comprises an adjusting motor, a driving gear, a driven gear, a driving sleeve, a vertical bevel gear, a horizontal bevel gear and a moving sleeve, a support is arranged on the side wall of the tower body, the adjusting motor and the driving gear are rotationally connected to the support, the driving gear is fixedly connected to the output end of the adjusting motor, the three-way pipe comprises a horizontal pipe, a lower vertical pipe and an upper vertical pipe, the driving sleeve is rotationally sleeved on the horizontal pipe, the driven gear is fixedly connected to the end of the driving sleeve in the radial direction, the driving gear is engaged with the driven gear, the moving sleeve is sleeved on the upper vertical pipe, the horizontal bevel gear is rotationally connected to the upper vertical pipe in the radial direction, the vertical bevel gear is fixedly connected to the end of the driving sleeve, the vertical bevel gear is engaged with the horizontal bevel gear, a control member is arranged in the moving sleeve, the driving gear controls the control member to drive the moving sleeve to move up and down along the upper vertical pipe, and the upper spraying pipe is connected to the moving sleeve and is communicated with the moving sleeve in the interior.

[0015] The further arrangement of the present application is that the control member comprises a guide rod, a guide hole, a fixed block, an annular sliding slot and a sliding column, the guide rod is axially arranged on the horizontal bevel gear, the guide hole is axially arranged below the moving sleeve, the guide rod is movably inserted into the guide hole, the fixed block is axially fixedly connected to the upper vertical pipe inside the moving sleeve, the annular sliding slot is annularly formed in the side surface of the fixed block, the moving sleeve is slidably connected to the outside of the fixed block, and the sliding column is radially fixedly connected to the inside of the moving sleeve and slidably connected to the annular sliding slot.

[0016] The further arrangement of the present application is that the annular sliding slot on the fixed block is arranged at an inclined angle.

[0017] By adopting the above technical scheme, the motor drives the driving gear to rotate, the driving gear drives the driven gear to rotate, the driven gear drives the driving sleeve to rotate at the same time, the driving sleeve drives the horizontal bevel gear to rotate through the vertical bevel gear, in the process of rotation of the horizontal bevel gear, the guide rods on both sides of the horizontal bevel gear are inserted into the moving sleeve, so that the horizontal bevel gear drives the moving sleeve to rotate at the same time through the guide rods, since the sliding column is radially fixedly connected to the inside of the moving sleeve and slidably connected to the annular sliding slot of the fixed block, when the moving sleeve rotates, the sliding column rotates along the annular sliding slot, since the height of the annular sliding slot on the fixed block is not uniform, the height of one side of the annular sliding slot on the fixed block is higher than that of the other side, so that the sliding column drives the moving sleeve to move up and down when moving in the annular sliding slot, further driving the upper spraying pipe to rise, increasing the distance between the upper spraying pipe and the lower spraying pipe, increasing the reaction channel of the flue gas and the spraying liquid sulfuric acid, so that the ammonia nitrogen compound in the flue gas can fully react with the concentrated sulfuric acid.

[0018] The further arrangement of the present application is that the reaction filler is provided below the guide plate, and the guide plate is inclined to the axis of the tower body.

[0019] By adopting the above technical scheme, the arrangement of the guide plate can avoid the flue gas from escaping along the wall, and the guide plate can concentrate the flue gas in the middle of the tower body, so that the flue gas diffuses upward from the middle, improving the reaction and washing degree of the flue gas.

[0020] The present application has the following beneficial effects:

[0021] 1. The application adopts a new combined process of "one-stage fine denitration + two-stage purification", which can ensure that the product analysis nitrate indicators are qualified. First, one-stage fine denitration process is adopted: that is, the nitrogen monoxide is removed after being oxidized by ozone and then absorbed by dry concentrated acid. Specifically, an ozone generator is arranged before the entrance of the drying tower of the flue gas into the dry absorption process. The ozone generator must be arranged after the acid-making purification electric demisting and before the entrance of the drying tower. The ozone generator is used to oxidize NO in the flue gas into high-valence nitrogen oxides, which are then absorbed by the circulating 93% acid in the drying tower. The one-stage fine denitration process can remove more than 90% of nitrogen oxides, so that the content of nitrogen oxides in the flue gas entering the acid-making conversion process is reduced to below 50 mg / m3.

[0022] 2. Two-stage purification process is adopted: that is, precision filter purification + nicotinic acid washing purification process. The purpose of the first-stage precision filter purification is to remove the conversion catalyst dust carried by the flue gas. The purpose of the second-stage nicotinic acid washing purification is to remove a small amount of nitrogen monoxide in the flue gas which is not removed by the first-stage fine denitration (the principle is that nitrogen monoxide generates high-valence nitrogen oxides in the acid-making conversion process, which can be dissolved in the nicotinic acid in the nicotinic acid washing tower to generate nitrosyl sulfuric acid). Finally, through the use of the above new combined process, the nitrate content in the finished product analysis is completely up to standard. In this process, the nicotinic acid is regularly discharged to the drying tower, and the concentrated sulfuric acid produced in the drying tower can reach GB / T 534-2014 first-class product, which can be sold externally, and has good economic benefits.

[0023] 3. The first circulation pipe and the second circulation pipe are arranged between the drying tower and the nicotinic acid washing tower. Since the sulfuric acid in the liquid tank of the drying tower will be periodically discharged as industrial concentrated sulfuric acid, the circulating liquid in the drying tower is reduced, and the concentrated sulfuric acid at the bottom of the nicotinic acid washing tower will supplement the circulating liquid of the drying tower through the first circulation pipe. At the same time, since the concentration of the concentrated sulfuric acid in the nicotinic acid washing tower will further increase during the reaction process, in order to maintain the concentration balance of the concentrated sulfuric acid in the nicotinic acid washing tower, the lower concentration of the concentrated sulfuric acid in the drying tower will be transported to the nicotinic acid washing tower through the second circulation pipe, so as to maintain the balance of the volume and concentration of the concentrated sulfuric acid in the drying tower and the nicotinic acid washing tower.

[0024] 4、The adjusting motor in the distance adjusting mechanism drives the driving gear to rotate, the driving gear drives the driven gear to rotate, and the driven gear drives the driving sleeve to rotate, the driving sleeve drives the horizontal bevel gear to rotate through the vertical bevel gear, and the horizontal bevel gear rotates, and the horizontal bevel gear drives the moving sleeve to rotate through the guide rods, the moving sleeve is internally fixedly connected with a sliding column, the sliding column is clamped in the annular sliding groove in the fixed block, and the sliding column rotates along the annular sliding groove when the moving sleeve rotates, and the height of the annular sliding groove on one side of the fixed block is higher than that on the other side, so that the moving sleeve moves up and down when the sliding column moves in the annular sliding groove, the upper spraying pipe is further lifted, the distance between the upper spraying pipe and the lower spraying pipe is increased, the reaction channel of flue gas and spraying liquid sulfuric acid is increased, and the ammonia-nitrogen compound in the flue gas can be more fully reacted with concentrated sulfuric acid. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0026] Figure 1 is the process flow diagram of the multi-stage denitration system for preparing pure sulfuric acid from smelting flue gas.

[0027] Figure 2 is the internal structure schematic diagram of the nicotinic acid washing tower in the present application.

[0028] Figure 3 is the spraying system structure schematic diagram in the present application.

[0029] Figure 4 is the distance adjusting mechanism structure schematic diagram in the present application.

[0030] Figure 5 is the control piece explosion structure schematic diagram in the present application.

[0031] Figure 6 is the moving sleeve cross-section structure schematic diagram in the present application.

[0032] In the figure, 1. tower body; 11. smoke inlet; 12. smoke outlet; 13. liquid tank; 14. reaction filler; 15. demisting filler; 16. guide plate; 2. spray system; 21. liquid delivery pipe; 22. T-piece; 221. horizontal pipe; 222. lower vertical pipe; 223. upper vertical pipe; 23. upper spray pipe; 24. lower spray pipe; 25. spray head; 3. distance adjustment mechanism; 31. adjustment motor; 32. driving gear; 33. driven gear; 34. driving sleeve; 35. vertical bevel gear; 36. horizontal bevel gear; 361. guide rod; 37. movable sleeve; 371. guide hole; 372. sliding column; 38. fixing block; 381. annular slide. DETAILED DESCRIPTION

[0033] The technical solutions of the present invention will be described clearly and completely below with reference to specific embodiments. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0034] Examples, such as Figure 1 As shown, a first-level fine denitrification system and a second-level purification system, the first-level fine denitrification system includes an ozone generator and a drying tower, wherein the ozone generator is arranged at the flue of the smoke inlet 11 of the drying tower, and the second-level purification system includes a precision filter and a nicotinic acid washing tower. The flue gas passing through the drying tower will undergo an ammonia nitrogen conversion process to convert low-valent nitrogen into high-valent nitrogen. The flue gas after the ammonia nitrogen conversion process is passed into the precision filter for filtration, and the smoke outlet 12 of the precision filter is communicated with the smoke inlet 11 of the nicotinic acid washing tower. The liquid tank 13 at the bottom of the drying tower is communicated with the liquid tank 13 below the nicotinic acid washing tower through a first circulation pipe and a second circulation pipe.

[0035] The NOx content of flue gas from non-ferrous metal smelting furnaces is as high as 500-2000 mg / Nm 3 , enters the acid production system purification process through the waste heat boiler, electrostatic precipitator, and high-temperature fan; the nitrogen oxide content in the flue gas leaving the secondary electrostatic precipitator is 500-1000mg / Nm 3 If this flue gas is directly fed into the dry absorption conversion process, part of the NO will be converted into high-valent nitrogen oxides during the conversion process and then absorbed by concentrated sulfuric acid, which will cause the nitrate content in the analytical pure sulfuric acid to exceed the standard. By installing an ozone oxidation generator before the inlet of the drying tower at the outlet of the electrostatic demister in the purification process, the ozone denitrification efficiency is above 95%, which oxidizes the low-valent NO in the flue gas into high-valent nitrogen oxides and then absorbs them by the 93% circulating concentrated sulfuric acid in the drying tower, reducing the nitrogen oxide content in the flue gas entering the analytical pure process to 50mg / m 3Hereinafter, this is a primary fine denitration. Meanwhile, in the subsequent absorption method analysis pure process, a precision filter + nicotinic acid washing purification tower + analytical pure absorption tower process is adopted, which is a two-stage purification. In this way, the flue gas is subjected to primary fine denitration and two-stage purification, so that the nitrate content in the analytical pure product completely meets the standard.

[0036] The present application adopts a new combined process of "primary fine denitration + two-stage purification", which can ensure that the nitrate index of the product meets the standard. First, the primary fine denitration process is adopted: the nitric oxide is removed by being absorbed by dry concentrated acid after being oxidized by ozone. Specifically, an ozone generator is arranged before the flue gas enters the drying tower of the dry absorption process. The ozone generator must be arranged after the acid-making purification electric demisting and before the inlet of the drying tower. The ozone generator is used to oxidize NO in the flue gas to high-valence nitrogen oxides, which are then absorbed by the circulating 93% acid in the drying tower. This primary fine denitration process can remove more than 90% of nitrogen oxides, so that the nitrogen oxide content in the flue gas entering the acid-making conversion process is reduced to 50 mg / m 3 Then, the two-stage purification process is adopted: precision filter purification + nicotinic acid washing purification process. The primary precision filter purification is to remove the conversion catalyst dust carried by the flue gas. The secondary nicotinic acid washing purification is to remove a small amount of nitric oxide in the flue gas that is not removed by the primary fine denitration. The nitric oxide generates high-valence nitrogen oxides in the acid-making conversion process, which can be dissolved in the nicotinic acid to generate nitroso sulfuric acid in the nicotinic acid washing tower. Finally, the above new combined process makes the nitrate content in the analytical pure product completely meet the standard. In this process, the nicotinic acid is regularly discharged to the drying tower, and the concentrated sulfuric acid produced in the drying tower can reach the first-class product of GB / T534-2014, which can be sold externally, and has good economic benefits.

[0037] The mass fraction of the circulating liquid at the bottom of the drying tower is 93% sulfuric acid. The mass fraction of the circulating liquid in the nicotinic acid washing tower is 105% sulfuric acid. A first circulating pipe and a second circulating pipe are arranged between the drying tower and the nicotinic acid washing tower. Since the sulfuric acid in the internal liquid tank 13 of the drying tower will be regularly discharged as industrial concentrated sulfuric acid, the circulating liquid in the drying tower is reduced, and the concentrated sulfuric acid at the bottom of the nicotinic acid washing tower will supplement the circulating liquid of the drying tower through the first circulating pipe. At the same time, since the concentration of the concentrated sulfuric acid in the nicotinic acid washing tower will further increase in the reaction process, in order to maintain the concentration balance of the concentrated sulfuric acid in the nicotinic acid washing tower, the lower concentration of the concentrated sulfuric acid in the drying tower will be transported to the nicotinic acid washing tower through the second circulating pipe, so as to maintain the balance of the volume and concentration of the concentrated sulfuric acid in the drying tower and the nicotinic acid washing tower.

[0038] The precision filter inner membrane is coated with a polytetrafluoroethylene coating. The precision filter device in the application adopts stainless steel 316L material, and the filter inner cylinder adopts imported polytetrafluoroethylene coating film, special process preparation, to ensure stable operation of the device; the nicotinic acid washing tower device shell adopts stainless steel 316L material, lined with special acid-resistant ceramic tiles, which has good adaptability to the mixed environment of concentrated nitric acid and concentrated sulfuric acid, and is also suitable for high-temperature concentrated acid circulation spraying and washing conditions.

[0039] As shown in Figure 2 、 Figure 3 The nicotinic acid washing tower includes a tower body 1, an inlet smoke port 11 and an outlet smoke port 12 arranged on the tower body 1, and the tower body 1 is sequentially provided with a liquid tank 13, a reaction filler 14, a spraying system 2 and a demisting filler 15 from bottom to top, the spraying system 2 includes a liquid feeding pipe 21, a three-way pipe 22, an upper spraying pipe 23 and a lower spraying pipe 24, the liquid feeding pipe 21 is in communication with the liquid tank 13 below the nicotinic acid washing tower and the three-way pipe 22, the upper spraying pipe 23 is in communication with the upper part of the three-way pipe 22, the lower spraying pipe 24 is in communication with the lower part of the three-way pipe 22, a plurality of spray heads 25 are arranged on the upper spraying pipe 23 and the lower spraying pipe 24, a distance adjusting mechanism 3 is arranged between the upper spraying pipe 23 and the lower spraying pipe 24, and the distance adjusting mechanism 3 drives the upper spraying pipe 23 to move close to or away from the lower spraying pipe 24.

[0040] By adopting the above technical scheme, the content of tail gas NOx can be further reduced, and the ammonia nitrogen absorption rate can be improved. When the content of ammonia nitrogen in flue gas is high, the distance between the upper spraying pipe 23 and the lower spraying pipe 24 is increased through the distance adjusting mechanism 3, so that the reaction channel of flue gas and spraying liquid sulfuric acid is increased, and the ammonia nitrogen compounds in flue gas can react with concentrated sulfuric acid more fully.

[0041] As shown in Figure 3 、 Figure 4 、 Figure 5As shown, the pitch adjustment mechanism 3 includes an adjusting motor 31, a driving gear 32, a driven gear 33, a driving sleeve 34, a vertical bevel gear 35, a horizontal bevel gear 36, and a movable sleeve 37. The side wall of the tower body 1 is provided with a bracket, the adjusting motor 31 and the driving gear 32 are rotatably connected to the bracket, the driving gear 32 is fixedly connected to the output end of the adjusting motor 31, the three-way pipe 22 includes a horizontal pipe 221, a lower vertical pipe 222 and an upper vertical pipe 223, the driving sleeve 34 is rotatably sleeved on the horizontal pipe 221, and the driven gear 33 is radially fixedly connected to the driving sleeve 34 The end of the driving gear 32 is meshed with the driven gear 33, the movable sleeve 37 is sleeved on the upper vertical tube 223, the horizontal bevel gear 36 is radially rotated and connected to the upper vertical tube 223, the vertical bevel gear 35 is fixedly connected to the end of the driving sleeve 34, the vertical bevel gear 35 is meshed with the horizontal bevel gear 36, a control member is provided in the movable sleeve 37, the driving gear 32 controls the control member to drive the movable sleeve 37 to move up and down along the upper vertical tube 223, and the upper spray pipe 23 is connected to the movable sleeve 37 and is internally connected.

[0042] like Figure 5 、 Figure 6 As shown, the control component includes a guide rod 361, a guide hole 371, a fixed block 38, an annular groove 381, and a sliding column 372. The guide rod 361 is axially arranged on the horizontal bevel gear 36, and a guide hole 371 is axially arranged below the movable sleeve 37. The guide rod 361 is movably inserted into the guide hole 371. The upper vertical tube 223 located inside the movable sleeve 37 is axially fixedly connected with a fixed block 38. An annular groove 381 is annularly opened on the side surface of the fixed block 38. The movable sleeve is slidably connected to the outside of the fixed block 38. A sliding column 372 is radially fixedly connected to the inside of the movable sleeve, and the sliding column 372 is slidably engaged in the annular groove 381.

[0043] like Figure 5 As shown, the annular sliding groove 381 located on the fixing block 38 is set at an inclined angle.

[0044] By adopting the technical scheme, the motor 31 drives the driving gear 32 to rotate, the driving gear 32 drives the driven gear 33 to rotate, the driven gear 33 drives the driving sleeve 34 to rotate, the driving sleeve 34 drives the vertical bevel gear 35 to rotate, the vertical bevel gear 35 drives the horizontal bevel gear 36 to rotate, the horizontal bevel gear 36 drives the guide rod 361 to rotate, the guide rod 361 drives the moving sleeve 37 to rotate, the moving sleeve 37 drives the sliding column 372 to rotate, the sliding column 372 drives the fixed block 38 to move up and down, the fixed block 38 drives the upper spraying pipe 23 to move up and down, the upper spraying pipe 23 drives the lower spraying pipe 24 to move up and down, and the lower spraying pipe 24 drives the reaction filler 14 to move up and down. Therefore, the ammonia-nitrogen compound in the flue gas can be fully reacted with the concentrated sulfuric acid.

[0045] As shown in Figure 2 The reaction filler 14 is provided below the guide plate 16, and the guide plate 16 is inclined to the axis of the tower body 1. The guide plate 16 can avoid the flue gas from escaping along the wall, and can concentrate the flue gas in the middle of the tower body 1, so that the flue gas diffuses upward from the middle, thereby improving the reaction washing degree of the flue gas.

[0046] The working principle of a smelting flue gas multi-stage denitration system for preparing pure sulfuric acid is as follows: the flue gas from non-ferrous metal smelting furnace has a high NOx content of 500-2000 mg / Nm3, and is purified in the acid making system through a waste heat boiler, an electric dust collector and a high-temperature fan; the NOx content in the flue gas after the second electric dust removal is 500-1000 mg / Nm3. If the flue gas is directly introduced into the dry absorption conversion process, part of the NO is converted into high-valence nitrogen oxides in the conversion process, which are then absorbed by the concentrated sulfuric acid, thereby causing the nitrate content in the pure sulfuric acid to exceed the standard. An ozone oxidation generator is specially arranged before the dry tower inlet of the purification process, the ozone denitration efficiency is above 95%, the low-valence NO in the flue gas is oxidized into high-valence nitrogen oxides, which are then absorbed by the 93% circulating concentrated sulfuric acid in the dry tower, so that the NOx content in the flue gas introduced into the pure sulfuric acid making process is reduced to below 50 mg / m3, which is a first-stage fine denitration. Meanwhile, in the subsequent absorption method for preparing pure sulfuric acid, a precision filter, a nicotinic acid washing purification tower and a pure absorption tower process are used, which is a two-stage purification. In this way, the flue gas is subjected to the first-stage fine denitration and the two-stage purification, so that the nitrate content in the pure sulfuric acid completely meets the standard.

[0047] The adjusting motor 31 in the distance adjusting mechanism 3 drives the driving gear 32 to rotate, the driving gear 32 drives the driven gear 33 to rotate, the driven gear 33 drives the driving sleeve 34 to rotate at the same time, the driving sleeve 34 drives the horizontal bevel gear 36 to rotate through the vertical bevel gear 35, in the process of rotating the horizontal bevel gear 36, because the guide rods 361 on both sides of the horizontal bevel gear 36 are inserted on the moving sleeve 37, so the horizontal bevel gear 36 drives the moving sleeve 37 to rotate through the guide rods 361 at the same time, because the sliding column 372 is radially fixedly connected in the moving sleeve 37, the sliding column 372 is clamped in the annular sliding groove 381 of the fixed block 38, so when the moving sleeve 37 rotates, the sliding column 372 rotates along the annular sliding groove 381, because the height of the annular sliding groove 381 on the fixed block 38 is not consistent, the height of one side of the annular sliding groove 381 on the fixed block 38 is higher than that of the other side, so that the sliding column 372 moves in the annular sliding groove 381 drives the moving sleeve 37 to move up and down, further drives the upper spraying pipe 23 to rise, the distance between the upper spraying pipe 23 and the lower spraying pipe 24 increases, the reaction channel of the flue gas and the spraying liquid sulfuric acid increases, so that the ammonia nitrogen compound in the flue gas can fully react with the concentrated sulfuric acid.

[0048] Finally, it should be noted that those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A system for producing analytically pure sulfuric acid from smelting flue gas using multi-stage denitrification, characterized by: It includes a primary fine denitration system and a secondary purification system, wherein the primary fine denitration system includes an ozone generator and a drying tower, wherein the ozone generator is arranged at the flue in front of the smoke inlet of the drying tower, and the secondary purification system includes a precision filter and a nicotinic acid washing tower. In the absorption method analytical pure process after the acid conversion section, the converted flue gas is subjected to secondary purification treatment using a precision filter, a nicotinic acid washing purification tower, and an analytical pure absorption tower process. The liquid tank at the bottom of the drying tower is connected to the liquid tank below the nicotinic acid washing tower through a first circulation pipe and a second circulation pipe, and the drying tower and the nicotinic acid washing tower are connected to each other; The nicotinic acid washing tower comprises a tower body (1), a smoke inlet (11) and a smoke outlet (12) arranged on the tower body (1); the tower body (1) is provided with a liquid tank (13), a reaction filler (14), a spray system (2) and a demisting filler (15) in order from bottom to top; the spray system (2) comprises a liquid feeding pipe (21), a three-way pipe (22), an upper spray pipe (23) and a lower spray pipe (24); the liquid feeding pipe (21) is connected to the liquid tank (13), the three-way pipe (22) and the lower spray pipe (24) below the nicotinic acid washing tower; (22), the upper spray pipe (23) is connected to the upper part of the three-way pipe (22), the lower spray pipe (24) is connected to the lower part of the three-way pipe (22), a plurality of spray heads (25) are provided on the upper spray pipe (23) and the lower spray pipe (24), a distance adjustment mechanism (3) is provided between the upper spray pipe (23) and the lower spray pipe (24), and the distance adjustment mechanism (3) drives the upper spray pipe (23) to approach or move away from the lower spray pipe (24); The pitch adjustment mechanism (3) comprises an adjusting motor (31), a driving gear (32), a driven gear (33), a driving sleeve (34), a vertical bevel gear (35), a horizontal bevel gear (36), and a movable sleeve (37). A bracket is provided on the side wall of the tower body (1). The adjusting motor (31) and the driving gear (32) are rotatably connected to the bracket. The driving gear (32) is fixedly connected to the output end of the adjusting motor (31). The three-way pipe (22) comprises a horizontal pipe (221), a lower vertical pipe (222), and an upper vertical pipe (223). The driving sleeve (34) is rotatably sleeved on the horizontal pipe (221). The driven gear (33) is radially fixedly connected to the driving sleeve ( The movable sleeve (37) is sleeved on the upper vertical tube (223), the horizontal bevel gear (36) is connected to the upper vertical tube (223) in a radially rotating manner, the vertical bevel gear (35) is fixedly connected to the end of the drive sleeve (34), the vertical bevel gear (35) is engaged with the horizontal bevel gear (36), a control member is provided in the movable sleeve (37), the drive gear (32) controls the control member to drive the movable sleeve (37) to move up and down along the upper vertical tube (223), and the upper spray pipe (23) is connected to the movable sleeve (37) and is internally connected; The control component includes a guide rod (361), a guide hole (371), a fixed block (38), an annular groove (381), and a sliding column (372). The guide rod (361) is axially arranged on the horizontal bevel gear (36). A guide hole (371) is axially arranged below the movable sleeve (37). The guide rod (361) is movably inserted into the guide hole (371). A fixed block (38) is axially fixedly connected to the upper vertical tube (223) inside the movable sleeve (37). An annular groove (381) is annularly opened on the side of the fixed block (38). The movable sleeve (37) is slidably connected to the outside of the fixed block (38). A sliding column (372) is radially fixedly connected to the inside of the movable sleeve (37). The sliding column (372) is slidably engaged in the annular groove (381).

2. The system for producing analytically pure sulfuric acid from smelting flue gas by multi-stage denitrification according to claim 1, characterized in that: The circulating liquid at the bottom of the drying tower is 93% sulfuric acid by mass.

3. The system for producing analytically pure sulfuric acid from smelting flue gas by multi-stage denitrification according to claim 1, characterized in that: The mass fraction of the circulating liquid in the nicotinic acid washing tower is 105% sulfuric acid.

4. The system for producing analytically pure sulfuric acid from smelting flue gas by multi-stage denitrification according to claim 1, characterized in that: The precision filter is coated with a polytetrafluoroethylene coating.

5. The system for producing analytically pure sulfuric acid from smelting flue gas by multi-stage denitrification according to claim 1, characterized in that: The annular sliding groove (381) located on the fixed block (38) is set at an inclined angle.

6. The system for producing analytically pure sulfuric acid from smelting flue gas by multi-stage denitrification according to claim 1, characterized in that: A guide plate (16) is provided below the reaction filler (14), and the guide plate (16) is inclined toward the axis of the tower body (1).

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