Equipment for concentrating dilute sulphuric acid by using waste heat of tail gas

Abstract

The utility model relates to the field of waste heat recovery devices, and particularly discloses equipment for concentrating dilute sulphuric acid by using tail gas waste heat. The equipment structure is sequentially connected in series with the Venturi tube, the heat absorption unit and the gas-liquid separation assembly from top to bottom. In the using process, high-temperature tail gas enters through the contraction type inlet section of the Venturi tube, and meanwhile, dilute sulphuric acid to be concentrated is injected from the throat part. A low pressure zone is formed at the throat, which enables the dilute sulphuric acid to be rapidly and efficiently mixed with the gas. And then, the gas-liquid two-phase mixture is subjected to primary heat exchange in the diffusion section and flows into a heat absorption unit internally provided with an airflow grating layer. And finally, gas-liquid separation is completed in the gas-liquid separation assembly, and tail gas subjected to waste heat recovery is discharged. According to the equipment, efficient gas-liquid mixing is ensured, tail gas waste heat is fully utilized, the energy consumption cost of a dilute sulfuric acid concentration process is reduced, and energy conservation and emission reduction are realized.

Description

Technical Field

[0001] The utility model relates to the field of waste heat recovery devices, and particularly to a device for concentrating dilute sulfuric acid by using waste heat of tail gas. Background Art

[0002] Titanium dioxide, whose main component is titanium dioxide (TiO2), is an important white pigment and is widely used in industries such as coatings, plastics, and papermaking. The sulfuric acid method is a commonly used method for preparing titanium dioxide, which mainly includes the following steps:

[0003] Pretreatment of titanium ore: removing impurities and increasing the content of titanium dioxide.

[0004] Acid digestion: mixing the treated titanium ore with concentrated sulfuric acid and reacting under high-temperature conditions to produce a titanium sulfate solution and by-products.

[0005] Hydrolysis: after the titanium sulfate solution is diluted and cooled, seeds are added for hydrolysis to produce metatitanic acid of titanium dioxide.

[0006] Washing, drying and calcination: metatitanic acid is washed repeatedly to remove soluble impurities, and after drying, it is calcined at high temperature to obtain titanium dioxide.

[0007] During the hydrolysis process, the titanium sulfate solution is diluted by a large amount of water, generating a large amount of dilute sulfuric acid. And during the washing process, in order to remove soluble impurities in metatitanic acid, a large amount of water is used, thus generating a washing solution containing dilute sulfuric acid. Recycling dilute sulfuric acid not only helps with the recycling of resources but also reduces environmental pollution.

[0008] Titanium dioxide is obtained after high-temperature calcination of metatitanic acid. The temperature of the tail gas after high-temperature calcination is as high as 350°C - 380°C. Usually, the high-temperature tail gas discharged from the tail of the calcination kiln is settled for dust in the settling chamber. The settled tail gas is cooled by circulating water spray absorption. After cooling, the gas enters the scrubbing tower to continue cooling and defoaming. Finally, after defoaming, the gas enters the electrostatic demister to remove the SO3 acid mist in the tail gas under the action of an electric field, and then is further treated in an alkali scrubbing tower and discharged after reaching the standard. However, by using circulating water spray for cooling, the heat in the tail gas and the SO3 acid mist cannot be effectively recovered and utilized, resulting in a relatively high production cost of titanium dioxide and being unfavorable for energy conservation and emission reduction.

[0009] Chinese Patent Application CN110523158A discloses a system for comprehensive collaborative treatment of tail gas from the calcination of a titanium dioxide rotary kiln, which specifically discloses waste acid liquid concentration: the flue gas passing through the flue gas cooler enters the Venturi acid liquid concentrator and contacts the sulfuric acid solution sprayed from the acid liquid pipe. The temperature of the flue gas is reduced to the saturation state, that is, 60 - 80°C. At the same time, the water in the waste acid liquid is evaporated, and the concentration of the waste water liquid is concentrated from the original 20% to 30% and enters the acid liquid storage tank of the pre-concentrator, and is transported to the acid recovery device in the factory area for reuse through a sulfuric acid circulation pump.

[0010] The flue gas of this patent comes into contact with sulfuric acid solution sprayed by the acid pipe in the Venturi acid concentrator. There are two problems in the technology of this part:

[0011] Firstly, after the flue gas exchanges heat in the cooler, its temperature is relatively low, and the effect on the evaporation and concentration of waste acid solution is poor.

[0012] Secondly, when the flue gas exchanges heat in the cooler, the restricted flow rate of the coil pipe is relatively low, and the effect on the dispersion of waste acid solution is poor.

[0013] Therefore, for the concentration of waste acid solution in the solution disclosed in this patent, it is necessary to rely on large-flow circulating heat absorption, which increases the energy consumption of the system. Moreover, for the two-stage flue gas desulfurization tower and flue gas condenser of this patented technology, the repeated heat transfer of the tail gas reduces the system reliability and the heat utilization rate is not good.

[0014] Therefore, researching a device for concentrating dilute sulfuric acid using the waste heat of tail gas is of great significance for utilizing the waste heat of tail gas in the titanium dioxide preparation process, reducing costs, saving energy and reducing emissions. Summary of the Utility Model

[0015] The purpose of the present utility model is to overcome the problem that the waste heat of the calcination tail gas in the titanium dioxide preparation process in the prior art has not been reasonably utilized, and to provide a device for concentrating dilute sulfuric acid using the waste heat of tail gas.

[0016] In short, the device structure of the present utility model is a Venturi tube, a heat absorption unit and a gas-liquid separation component connected in series from top to bottom. By precisely adjusting the gas-liquid inlet position and equipping the heat absorption unit with an air flow grid layer, efficient gas-liquid mixing is ensured, achieving a high waste heat absorption rate, making full use of the waste heat of tail gas, reducing the energy consumption cost of the dilute sulfuric acid concentration process, and at the same time achieving tail gas purification and energy conservation and emission reduction.

[0017] In order to achieve the above purpose, the technical solution adopted by the present utility model is:

[0018] A device for concentrating dilute sulfuric acid using the waste heat of tail gas, comprising:

[0019] A Venturi tube, the Venturi tube successively includes an inlet section, a throat and a diffuser section from top to bottom. The inlet section is connected with a tail gas conveying pipe, and the side wall of the throat is tangentially connected with a dilute sulfuric acid conveying pipe;

[0020] A heat absorption unit, the heat absorption unit is connected to the bottom of the Venturi tube, and an air flow grid layer is arranged in the heat absorption unit;

[0021] A gas-liquid separation component, the gas-liquid separation component is connected to the bottom of the heat absorption unit.

[0022] The structure of the waste heat concentrating dilute sulfuric acid equipment of the present utility model is a waste heat absorption system composed of a Venturi tube, a heat absorption unit, and a gas-liquid separation component connected in series from top to bottom. During use, high-temperature tail gas enters through the converging inlet section of the Venturi tube. The inlet section is a reduced-diameter section with a reduced cross-sectional area, an increased tail gas flow velocity, and a reduced static pressure. Then, the dilute sulfuric acid to be concentrated is injected from the throat. When the high-temperature tail gas quickly passes through the throat of the Venturi tube, a low-pressure area with the highest flow velocity and the lowest static pressure is formed in the throat, enabling the dilute sulfuric acid to be quickly and efficiently sucked into the throat of the Venturi tube and fully mixed with the tail gas. Then, in the diffuser section, due to the enlarged cross-sectional area and the reduced gas flow velocity, the dilute sulfuric acid is broken into tiny droplets by the gas flow due to viscous friction and eddy current effects, and heat exchange is quickly completed, reducing the temperature of the tail gas and quickly concentrating the dilute sulfuric acid. Therefore, the Venturi tube part can significantly improve the heat absorption efficiency of the dilute sulfuric acid for the tail gas.

[0023] Subsequently, the gas-liquid mixture of the dilute sulfuric acid and the tail gas flows into the heat absorption unit. An air flow grid layer is provided in the heat absorption unit. Most of the dilute sulfuric acid splashes onto the air flow grid and flows down at a relatively lower speed than the tail gas, prolonging the heat absorption time of the gas-liquid mixture and further improving the heat absorption efficiency. In addition, the air flow grid layer can help remove some particulate matter in the tail gas. Finally, gas-liquid separation is completed in the gas-liquid separation component, and the tail gas after waste heat recovery is discharged.

[0024] The equipment structure of the present utility model is simple. By precisely adjusting the gas-liquid inlet positions and equipping the heat absorption unit with an air flow grid layer, efficient gas-liquid mixing is ensured, a high waste heat absorption efficiency is achieved, the waste heat of the tail gas is fully utilized, the energy consumption cost of the dilute sulfuric acid concentration process is reduced, and energy conservation and emission reduction are realized.

[0025] As a preferred embodiment of the present utility model, a graphite layer lining is provided on the inner wall of the Venturi tube and / or the heat absorption unit. By providing the graphite lining, the corrosion resistance and heat insulation performance of the device can be ensured.

[0026] As a preferred embodiment of the present utility model, the tail gas delivery pipe is connected to the top surface of the inlet section. The tail gas is input from top to bottom from the top surface, having a certain downward impact force, which can better mix with the dilute sulfuric acid in the throat and has a higher heat absorption efficiency.

[0027] As a preferred embodiment of the present utility model, a plurality of air flow grid layers are vertically and spaced apart in the heat absorption unit. Vertically and spacingly arranging multiple air flow grid layers can not only prolong the heat absorption time but also better remove particulate matter in the tail gas.

[0028] Furthermore, the air flow grid layer is arranged at an angle of 60-90° with the axis of the Venturi tube.

[0029] Further, the included angle between adjacent air flow grille layers is 0 - 30°.

[0030] As a preferred embodiment of the present utility model, the distance between adjacent two air flow grille layers is 1000 mm - 1500 mm. A reasonable distance can further improve the waste gas waste heat absorption efficiency. Preferably, the distance between adjacent two air flow grille layers is 1000 mm - 1200 mm.

[0031] As a preferred embodiment of the present utility model, the gas - liquid separation assembly includes a reaction tank and a sedimentation tank. The reaction tank is connected to the bottom of the heat absorption unit. An overflow channel is arranged on the side of the reaction tank. The sedimentation tank is used to receive the liquid overflowing from the overflow channel, and a gas discharge port is arranged at the top of the sedimentation tank. The pre - concentrated sulfuric acid generated by the heat absorption unit enters the reaction tank for a certain precipitation and then enters the sedimentation tank through the overflow channel for further precipitation. The waste gas after waste heat recovery is discharged from the top of the sedimentation tank.

[0032] As a preferred embodiment of the present utility model, the reaction tank and the sedimentation tank are of concrete structure, and a graphite layer lining is arranged inside the reaction tank and the sedimentation tank. To ensure the corrosion resistance of the structure and the heat preservation and insulation performance.

[0033] Further, the thickness of the graphite layer lining is 30 - 150 mm, preferably 40 - 100 mm, such as 50 mm.

[0034] As a preferred embodiment of the present utility model, a filter screen is arranged on the overflow channel. The filter screen can purify the impurities in the reaction tank. The reaction tank recovers various valuable metal elements carried in the calcination waste gas, such as impurity metal components like Fe2O3, Al2O3, etc. originally mixed in the metatitanic acid solution, making the sulfuric acid overflowing into the sedimentation tank purer.

[0035] As a preferred embodiment of the present utility model, it further includes a dilute sulfuric acid return pipe. One end of the dilute sulfuric acid return pipe is connected to the reaction tank, and the other end is connected to the dilute sulfuric acid delivery pipe. Returning the pre - concentrated dilute sulfuric acid in the reaction tank to the Venturi tube for re - pre - concentration can obtain a higher concentrated solution using the waste heat of the waste gas, further reducing the energy consumption cost for the subsequent sulfuric acid treatment process.

[0036] As a preferred embodiment of the present utility model, it further includes a concentration system. The concentration system is connected to the sedimentation tank and is used to recover and re - concentrate the supernatant of the sedimentation tank. The supernatant of the sedimentation tank can obtain sulfuric acid with a higher concentration through the concentration system.

[0037] Compared with the prior art, the beneficial effects of the present utility model:

[0038] 1. The equipment structure involved in the present utility model is successively connected in series with a Venturi tube, a heat absorption unit, and a gas-liquid separation assembly from top to bottom. During use, the high-temperature tail gas enters through the convergent inlet section of the Venturi tube. At the same time, pre-concentrated dilute sulfuric acid is injected from the throat. When the high-temperature tail gas passes through the throat of the Venturi tube, the flow rate increases and the static pressure decreases, forming a low-pressure area in the throat. This enables the dilute sulfuric acid to mix with the gas quickly and efficiently, significantly improving the heat absorption efficiency. Subsequently, the gas-liquid mixture flows into the heat absorption unit after preliminary heat exchange in the diffuser section. The heat absorption unit is provided with an air flow grid layer, which not only prolongs the heat absorption time of the gas-liquid mixture but also further improves the heat absorption efficiency and helps remove some particulate matter in the tail gas. Finally, gas-liquid separation is completed in the gas-liquid separation assembly, and the tail gas after waste heat recovery is discharged. The structure of this equipment is simple. By precisely adjusting the gas-liquid inlet positions and equipping the heat absorption unit with an air flow grid layer, efficient gas-liquid mixing is ensured, achieving a high waste heat absorption efficiency, making full use of the tail gas waste heat, reducing the energy consumption cost of the dilute sulfuric acid concentration process, and realizing energy conservation and emission reduction.

[0039] 2. For the equipment provided in this application, SO3 or acid mist in the tail gas is absorbed by the dilute sulfuric acid, reducing the supplement of alkali liquor in the alkali spray tail gas treatment process and lowering the production cost of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the equipment for concentrating dilute sulfuric acid by using the waste heat of the tail gas in the present utility model.

[0041] Markings in the figure:

[0042] 1 - Venturi tube; 11 - Inlet section; 111 - Tail gas delivery pipe; 12 - Throat; 121 - Dilute sulfuric acid delivery pipe; 13 - Diffuser section;

[0043] 2 - Heat absorption unit; 21 - Air flow grid layer;

[0044] 3 - Gas-liquid separation assembly; 31 - Reaction tank; 311 - Overflow channel; 312 - Dilute sulfuric acid reflux pipe; 32 - Sedimentation tank;

[0045] 4 - Concentration system. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] The following further describes the present utility model in detail with specific embodiments. However, this should not be understood that the scope of the above-mentioned subject matter of the present utility model is limited to the following embodiments. All technologies implemented based on the content of the present utility model belong to the scope of the present utility model.

[0047] Embodiment 1

[0048] During the preparation process of titanium dioxide, a large amount of dilute sulfuric acid is generated. Recycling the dilute sulfuric acid not only helps with the recycling of resources but also reduces environmental pollution. At the same time, during the preparation process of titanium dioxide, the calcination tail gas has a relatively high temperature. In the prior art, a large amount of water is used to spray and absorb the tail gas for cooling, which has a high cost and the waste heat is not recovered.

[0049] Using the waste heat of the tail gas to pre-concentrate the dilute sulfuric acid can reduce the energy consumption cost for the later concentration process of the dilute sulfuric acid. The waste heat of the tail gas can also be utilized as a resource, achieving energy conservation and emission reduction. For this reason, as Figure 1 shown, this embodiment provides an apparatus for concentrating dilute sulfuric acid using the waste heat of the tail gas, which includes a Venturi tube 1, a heat absorption unit 2, and a gas-liquid separation component 3 from top to bottom.

[0050] The Venturi tube 1 includes an inlet section 11, a throat 12, and a diffuser section 13 from top to bottom. The inlet section 11 is a trumpet-shaped contraction structure. The inlet section 11 is connected to a tail gas delivery pipe 111, and the throat 12 is connected to a dilute sulfuric acid delivery pipe 121. The high-temperature tail gas enters through the contraction-type inlet section 11 of the Venturi tube 1. At the same time, the dilute sulfuric acid to be concentrated is injected from the throat 12. When the high-temperature tail gas passes through the throat of the Venturi tube, the flow rate increases and the static pressure decreases, forming a low-pressure area at the throat. This enables the dilute sulfuric acid to be quickly and efficiently sucked in and mixed with the high-temperature tail gas, significantly improving the heat absorption efficiency of the dilute sulfuric acid. Subsequently, the gas-liquid mixture undergoes preliminary heat exchange in the diffuser section and flows into the heat absorption unit.

[0051] Among them, the inlet section 11 is the inlet part of the Venturi tube, and its cross-section gradually decreases. The throat 12 is the part with the smallest cross-section of the Venturi tube. Here, the tail gas flow rate reaches the maximum and the static pressure drops to the lowest. The diffuser section 13 has a gradually increasing cross-sectional area. In this section, the flow rate of the fluid begins to decrease while the pressure gradually recovers.

[0052] In some embodiments, a graphite layer lining is provided inside the Venturi tube 1. By setting the graphite lining, the corrosion resistance and heat insulation performance of the Venturi tube can be ensured.

[0053] In some embodiments, the tail gas delivery pipe 111 is connected to the top surface of the inlet section 11. The tail gas is input from the top downwards, having a certain downward impact force, which can better mix with the dilute sulfuric acid at the throat and has a higher heat absorption efficiency.

[0054] The heat absorption unit 2 is connected to the bottom of the Venturi tube 1, and an air flow grid layer 21 is provided inside the heat absorption unit 2. The provision of the air flow grid layer inside the heat absorption unit not only prolongs the heat absorption time of the gas-liquid mixture but also further improves the heat exchange efficiency and helps remove particulate matter from the tail gas.

[0055] In some embodiments, the inner wall of the heat absorption unit 2 is provided with a graphite layer lining. By providing the graphite lining, the corrosion resistance and heat preservation and insulation performance of the heat absorption unit can be ensured.

[0056] In some embodiments, a plurality of air flow grille layers 21 are vertically and spaced apart in the heat absorption unit 2. Vertically and spacing multiple air flow grille layers can not only extend the time for the dilute sulfuric acid and the tail gas to fully absorb heat, but also better remove some particulate matters in the tail gas.

[0057] In some embodiments, the interval between two adjacent air flow grille layers 21 is 1000 mm to 1500 mm. A reasonable spacing can further improve the tail gas waste heat absorption efficiency. Preferably, the interval between two adjacent air flow grille layers is 1000 mm to 1200 mm.

[0058] A gas-liquid separation assembly 3, the gas-liquid separation assembly 3 is connected to the bottom of the heat absorption unit 2. Gas-liquid separation is completed in the gas-liquid separation assembly, and the tail gas after waste heat recovery is discharged.

[0059] As Figure 1 shown, the gas-liquid separation assembly 3 includes a reaction tank 31 and a sedimentation tank 32. The reaction tank 31 is connected to the bottom of the heat absorption unit 2. An overflow channel 311 is provided on the side of the reaction tank 31. The sedimentation tank 32 is used to receive the liquid overflowing from the overflow channel 311. A gas discharge port is provided at the top of the sedimentation tank 32. The concentrated sulfuric acid flowing down from the heat absorption unit 2 enters the reaction tank 31, and after preliminary precipitation, it enters the sedimentation tank 32 through the overflow channel 311 for further precipitation. The tail gas after waste heat recovery is discharged from the top of the sedimentation tank 32. The reaction tank 31 and the sedimentation tank 32 are of concrete structure, and a graphite layer lining is provided inside the reaction tank 31 and the sedimentation tank 32 to ensure the structural corrosion resistance and heat preservation and insulation performance.

[0060] In some specific implementation cases, a filter screen is provided in the overflow channel 311. The filter screen can filter impurities in the reaction tank, ensure the purity of the sulfuric acid overflowing into the sedimentation tank, retain valuable metals and solids in the reaction tank 31, and initially complete the separation of sulfuric acid and other components.

[0061] As Figure 1 shown, it further includes a dilute sulfuric acid return pipe 312. One end of the dilute sulfuric acid return pipe 312 is connected to the reaction tank 31, and the other end is connected to the dilute sulfuric acid delivery pipe 121. Returning the pre-concentrated dilute sulfuric acid in the reaction tank 31 to the Venturi tube 1 for re-pre-concentration can obtain a higher concentrated liquid by using the waste heat of the tail gas, and further reduce the energy consumption cost for the subsequent sulfuric acid treatment process.

[0062] It also includes a concentration system 4, which is connected to the sedimentation tank 32 and used to recycle and reconcentrate the supernatant of the sedimentation tank 32. The supernatant of the sedimentation tank can obtain sulfuric acid with a higher concentration through the concentration system to obtain the sulfuric acid concentration that meets the production requirements.

[0063] The structure of this equipment is simple. By precisely adjusting the positions of the gas-liquid inlets and equipping the heat absorption unit with an air flow grid layer, efficient gas-liquid mixing is ensured, achieving a high waste heat absorption efficiency, making full use of the waste heat of the tail gas, reducing the energy consumption cost of the dilute sulfuric acid concentration process, realizing energy conservation and emission reduction, and facilitating popularization and utilization.

[0064] Unless otherwise specified, in the description of the specific embodiments of the present invention, the expression terms indicating the orientation or positional relationship such as "upper", "lower", "left", "right", "center", "inner", "outer", etc. are all based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product / equipment / device of the present invention is commonly used and placed. These terms of orientation or positional relationship are only for the convenience of describing the solution of the present invention or simplifying the description in the specific embodiments, so as to facilitate technicians to quickly understand the solution, rather than indicating or implying that a specific device / component / element must have a specific orientation or be constructed and operated in a specific positional relationship. Therefore, it should not be construed as a limitation to the present invention.

[0065] In addition, when terms such as "horizontal", "vertical", "hanging", "parallel" appear, it does not mean that the corresponding device / component / element is required to be absolutely horizontal or vertical or hanging or parallel, but can be slightly inclined or deviated. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined. Or, it can be simply understood that the corresponding device / component / element is set in the directions of "horizontal", "vertical", "hanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still play its role in the solution of the present invention.

[0066] In addition, when expressions such as "first", "second", "third", etc. appear in the terms, they are only used to distinguish the description of the same or similar components, and should not be understood as emphasizing or implying the relative importance of specific components.

[0067] In addition, in the description of the embodiments of the present utility model, "several", "multiple", and "a plurality of" represent at least two. It can be any case such as 2, 3, 4, 5, 6, 7, 8, 9, etc., and even can be a case where it exceeds 9.

[0068] In addition, in the description of the technical solution of the present utility model, unless otherwise clearly specified / defined / restricted, where the terms "set", "installed", "connected", "coupled", "provided with", "laid", "arranged" appear, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be connection means commonly used in the art such as welding, riveting, bolting, threaded connection, etc. Such a connection can be a mechanical connection, an electrical connection, or a communication connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components.

[0069] The above are only the preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A device for concentrating dilute sulfuric acid using waste heat from tail gas, characterized in that: include, A venturi tube (1), the venturi tube (1) comprising, from top to bottom, an inlet section (11), a throat section (12) and a diffusion section (13), the inlet section (11) being connected to an exhaust gas delivery pipe (111), and the side wall of the throat section (12) being tangentially connected to a dilute sulfuric acid delivery pipe (121); A heat absorption unit (2), the heat absorption unit (2) being connected to the bottom of the venturi tube (1), and an air flow grid layer (21) being arranged inside the heat absorption unit (2); A gas-liquid separation component (3), wherein the gas-liquid separation component (3) is connected to the bottom of the heat absorption unit (2).

2. The equipment for concentrating dilute sulfuric acid using waste heat from tail gas according to claim 1, characterized in that: The inner wall of the venturi tube (1) and / or the heat absorption unit (2) is provided with a graphite layer lining.

3. The equipment for concentrating dilute sulfuric acid using waste heat from tail gas according to claim 1, characterized in that: The exhaust gas delivery pipe (111) is connected to the top surface of the inlet section (11).

4. The equipment for concentrating dilute sulfuric acid using waste heat from tail gas according to claim 1, characterized in that: A plurality of airflow grid layers (21) are vertically spaced apart in the heat absorption unit (2).

5. The equipment for concentrating dilute sulfuric acid using waste heat from tail gas according to claim 4, characterized in that: The interval between two adjacent airflow grid layers (21) is 10 cm to 30 cm.

6. The equipment for concentrating dilute sulfuric acid using waste heat from tail gas according to any one of claims 1 to 5, characterized in that: The gas-liquid separation component (3) comprises a reaction tank (31) and a sedimentation tank (32); the reaction tank (31) is connected to the bottom of the heat absorption unit (2); an overflow channel (311) is provided on the side of the reaction tank (31); the sedimentation tank (32) is used to receive liquid overflowing from the overflow channel (311); and a gas discharge port is provided on the top of the sedimentation tank (32).

7. The equipment for concentrating dilute sulfuric acid using waste heat from tail gas according to claim 6, characterized in that: The reaction tank (31) and the sedimentation tank (32) are concrete structures, and graphite layer linings are provided inside the reaction tank (31) and the sedimentation tank (32).

8. The equipment for concentrating dilute sulfuric acid using waste heat from tail gas according to claim 6, characterized in that: The overflow channel (311) is provided with a filter screen.

9. The equipment for concentrating dilute sulfuric acid using waste heat from tail gas according to claim 6, characterized in that: It also includes a dilute sulfuric acid reflux pipe (312), one end of the dilute sulfuric acid reflux pipe (312) is connected to the reaction tank (31), and the other end is connected to the dilute sulfuric acid delivery pipe (121).

10. The equipment for concentrating dilute sulfuric acid using waste heat from tail gas according to claim 6, characterized in that: It also includes a concentration system (4), which is connected to the sedimentation tank (32) and is used to recover and re-concentrate the supernatant of the sedimentation tank (32).

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