Quenching purification device for sulfuric acid recovery

Abstract

The utility model discloses a quenching purification device for sulfuric acid recovery, which comprises a flue gas inlet section, a reducing section, a throat section, an expanding section and a settling section which are sequentially communicated from top to bottom, and the flue gas inlet section is provided with a gas phase inlet and a plurality of liquid phase spraying ports; the radial size of the reducing section is gradually reduced in the flue gas conveying direction; the diameter of the expanding section is gradually increased along the radial diameter of the flue gas conveying direction, a plurality of layers of liquid-phase spraying openings are formed in the expanding section, a plurality of atomizing nozzles are arranged on each layer of liquid-phase spraying opening, and two adjacent layers of liquid-phase spraying openings are arranged in a staggered manner; the settling section extends along the lower section of the expanding section, is provided with a cavity and is used for accommodating the cooled flue gas and carrying out gas-liquid separation; and a horizontal flue gas outlet connected with downstream equipment is formed in the side wall of the flue gas inlet pipe. According to the utility model, the venturi principle is adopted, the equipment construction cost and the system operation cost are saved while the quenching, absorbing and washing effects are ensured, and meanwhile, the problem that the gas-liquid interface of the venturi is easy to corrode is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of sulfuric acid recovery industry, in particular to a rapid cooling and purification device for sulfuric acid recovery. Background Art

[0002] The sulfuric acid industry is a fundamental chemical industry, and its development is closely linked to all sectors of the national economy. Since the 13th Five-Year Plan, a distinctive feature of my country's sulfuric acid industry has been green development. This industry has utilized a variety of sulfur-containing wastes, including hydrogen sulfide, a byproduct of petrochemical and coal chemical industries; waste acid from alkylation; ferrous sulfate, a byproduct of titanium dioxide; industrial gypsum; SO2 recovered from sintering flue gas; waste liquid from coking desulfurization; waste acid from acrylonitrile; waste acid from acetylene purification; and waste acid from lead-acid batteries. A large number of environmentally friendly acid-producing plants have been built in China. Sulfuric acid recovery plants, as environmentally friendly devices in the circular economy, have shown new vitality. In particular, the integration of sulfuric acid recovery processes with acrylonitrile plants has significantly promoted the large-scale development of the acrylonitrile industry.

[0003] The sulfuric acid recovery unit primarily utilizes a waste acid regeneration process, encompassing cracking, waste heat recovery, flue gas quenching and purification, reaction conversion, and absorption. Flue gas quenching and purification, a key step in the sulfuric acid recovery process, rapidly cools high-temperature flue gas, deeply scrubs dust, breaks down aerosols, and absorbs SO₃ in the flue gas, effectively preventing subsequent equipment corrosion and extending the equipment's operating cycle.

[0004] Dynamic wave and Venturi methods are commonly used for rapid cooling and purification in chemical plants. Dynamic wave is the most common method used in sulfuric acid recovery plants. Dynamic wave quenching equipment involves high-speed collision of high-temperature flue gas from a waste heat boiler with a large amount of circulating spray liquid in a reverse nozzle, forming a high-speed turbulent liquid film foam zone. Within this stable turbulent foam zone, the gas and liquid phases have a very large contact area, and the contact surface can be rapidly renewed, thereby achieving rapid cooling, scrubbing, and absorption of the gas phase. However, to achieve these goals, the dynamic wave requires a large liquid-to-gas ratio and a high liquid pressure head. This creates a high energy consumption and increases the operating cost of the device. Furthermore, the foam zone is a high-temperature, acidic environment that is susceptible to corrosion, requiring the use of high-temperature and acid-resistant materials, resulting in high equipment costs. Flue gas entrains a large number of liquid droplets after passing through the foam zone, requiring a large space for gas-liquid sedimentation. Therefore, dynamic wave quenching takes up a large area, increasing the construction cost of the device.

[0005] Chinese patent document CN203971733U discloses a reverse jet pipe for a power wave scrubber. The pipe consists of a reverse jet pipe body and a flue gas transition pipe. The upper end of the flue gas transition section is a vertical pipe body. The vertical pipe body is equipped with an overflow weir and a circular stepped mounting bracket at both ends. The liquid flowing out of the overflow weir forms an overflow water film on the inner wall of the reverse jet pipe body, which serves as an isolation and protection for the dilute sulfuric acid solution, reducing corrosion to the equipment, thereby reducing equipment material and equipment investment. However, it does not solve the problems of high energy consumption and large space occupied by the power wave.

[0006] The principle of Venturi quenching is that when high-temperature flue gas passes through the Venturi throat, the gas velocity increases, rapidly contacting the scrubbing liquid. Under the influence of the drag force at the gas-liquid interface, the circulating liquid is atomized into small droplets, which form a turbulent zone with the gas phase in the throat. The gas and liquid phases accelerate contact and collision, achieving a cooling and scrubbing effect on the high-temperature flue gas. In actual installations, Venturi tubes are generally used in flue gas dust removal or flue gas desulfurization industries, and are rarely used in sulfuric acid recovery units. This is because sulfuric acid recovery units contain large amounts of SO2 and a certain amount of SO3. The gas-liquid interface of the Venturi quencher is a hot, acidic environment, which is very likely to cause equipment corrosion.

[0007] Chinese patent CN215654605U discloses a wet treatment device for dust- and acid-containing waste gas. The exhaust gas to be treated is introduced into the inlet of a Venturi scrubber mechanism, and the exhaust gas outlet is connected to the exhaust gas inlet of a scrubber tower via an elbow in a connector. Several liquid spray pipes are introduced into the Venturi scrubber mechanism. A circulating water tank is located at the bottom of the scrubber tower, and the exhaust gas inlet is located above the circulating water tank within the scrubber tower. The scrubber tower also includes upper and lower liquid spray pipes located between the exhaust gas inlet and the scrubber tower outlet, as well as a liquid distributor located between the upper and lower liquid spray pipes. The circulating water tank is connected to a liquid collection tank via an overflow pipe. This wet treatment device offers efficient dust removal and cooling, and is compact and requires minimal space. However, it does not address the issue of high-temperature acid corrosion at the gas-liquid interface when high-sulfur flue gas from a sulfuric acid plant passes through the Venturi mechanism, making it highly susceptible to equipment corrosion during practical use.

[0008] In view of the characteristics of flue gas rapid cooling and purification in the sulfuric acid recovery industry, technical personnel in this field need to provide a rapid cooling and purification device for sulfuric acid recovery that can effectively solve the problems of high energy consumption and large space occupied by power waves, save equipment construction costs and system operating costs, and at the same time solve the problem of easy corrosion at the Venturi gas-liquid interface. Summary of the Invention

[0009] In order to solve the above problems, the utility model aims to provide a quenching purification device for sulfuric acid recovery that adopts the design principle of Venturi, which effectively solves the problems of high energy consumption and large space occupied by dynamic waves while ensuring the rapid cooling, absorption and washing effects, saves equipment construction costs and system operation costs, and solves the problem of easy corrosion of the gas-liquid interface of Venturi.

[0010] In order to achieve the above-mentioned purpose, a quenching purification device for sulfuric acid recovery is provided, and the technical solution adopted is as follows:

[0011] A quenching and purification device for sulfuric acid recovery comprises a flue gas inlet section, a diameter reduction section, a throat section, a diameter expansion section, and a sedimentation section, which are sequentially connected from top to bottom, wherein:

[0012] The flue gas inlet section has a gas phase inlet and is provided with a plurality of liquid phase spray ports;

[0013] The upper end of the diameter-reducing section is connected to the smoke inlet section, and the radial dimension of the diameter-reducing section along the smoke transmission direction gradually decreases;

[0014] The throat diameter is vertically extended downward along the lower end of the reduced diameter section;

[0015] The upper end of the expanded diameter section is connected to the lower end of the throat diameter, and the radial diameter of the expanded diameter section gradually increases along the flue gas transmission direction. The expanded diameter section is provided with multiple layers of liquid phase spray ports, each layer of liquid phase spray ports is arranged with multiple atomizing nozzles at intervals along the circumferential direction, and the liquid phase spray ports of two adjacent layers are staggered.

[0016] The settling section is provided with a cavity extending along the lower end of the expansion section for accommodating the cooled flue gas and performing gas-liquid separation by gravity settling; and a horizontal flue gas outlet is provided on the side wall of the settling section.

[0017] Preferably, the multiple liquid phase spray ports provided in the flue gas inlet section are distributed in a ring shape on the same horizontal plane, and the number of liquid phase spray ports is set to 3 to 8; the liquid phase spray ports are set at 15-75° along the tangent direction of the connection between the liquid phase spray ports and the device.

[0018] Preferably, the length L1 of the reduced diameter section is 300 to 1200 mm.

[0019] Preferably, the length L2 of the throat diameter is 200 to 1000 mm, and the gas phase flow rate of the flue gas through the throat diameter is 35 to 100 m / s.

[0020] Preferably, the length L3 of the expanded diameter section is 800-2000 mm.

[0021] Furthermore, the liquid phase spraying openings of the diameter expansion section are provided in two layers, upper and lower, and the distance L4 between the two layers of liquid phase spraying openings is 300 to 800 mm.

[0022] Furthermore, the atomizing nozzles in any layer of liquid phase spray openings in the expanded diameter section are uniformly spaced at 3 to 8 in the circumferential direction; and the two layers of liquid phase spray openings are uniformly staggered.

[0023] Preferably, the liquid phase spray port is inclined at 15-45 degrees to the horizontal plane, and the liquid phase spray density at 500-1000 mm below the lower end of the lower liquid phase spray port is 40-120 m 3 / (m 2 ·h).

[0024] Preferably, the upper wall of the horizontal smoke outlet is located at the lower end of the liquid phase coverage area formed by the expansion section; and the lower wall of the horizontal smoke outlet is higher than the bottom surface of the sedimentation section.

[0025] Preferably, the lower side of the sedimentation section is further connected to a cone bottom, and a sewage outlet is provided at the bottom of the cone bottom.

[0026] Furthermore, the cone angle θ of the cone bottom is 60 to 120°.

[0027] Beneficial effects:

[0028] 1) The utility model adopts the principle of Venturi to cool and quench the flue gas during the absorption and washing process, which greatly reduces the amount of liquid entrainment. Only a small separation and sedimentation space needs to be designed to achieve effective separation of gas and liquid, reducing the equipment footprint.

[0029] 2) The liquid phase spray port provided at the flue gas inlet section of the present invention can form a liquid film at the interface between the high-temperature flue gas and the liquid phase, thereby reducing the surface temperature of the equipment, effectively protecting the equipment and preventing high-temperature flue gas corrosion.

[0030] 3) The throat diameter design of the utility model can accelerate the gas flow rate, increase the kinetic energy of the gas, and quickly contact the washing liquid at the liquid spray port to form turbulence, break up the SO3 aerosol, and achieve the effect of rapid cooling, washing and absorption of SO3, thereby preventing subsequent equipment corrosion.

[0031] 4) The liquid phase spray nozzle provided in the expanded diameter section of the utility model atomizes the liquid phase into small droplets at a certain spray angle and sprays them into the rapid cooling purification device, and forms a liquid phase coverage area under the nozzle, so that the flue gas is rapidly cooled to about saturation temperature, which is convenient for subsequent gas-liquid separation.

[0032] 5) The utility model sets an appropriate cone angle at the cone bottom, which is conducive to the flow and discharge of sewage in the liquid phase and the washed solid dust.

[0033] 6) This device achieves the same washing and absorption effect as the power wave, and the required liquid-vapor ratio is only about half, and the liquid phase pressure is lower, so the energy consumption required during operation is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described below with reference to the accompanying drawings.

[0035] Figure 1 This is a schematic diagram of a rapid cooling and purification device for sulfuric acid recovery according to the present invention.

[0036] Description of Figure Numbers:

[0037] 1 shell; 1-1 smoke inlet section; 1-2 reduced diameter section; 1-3 throat diameter; 1-4 expanded diameter section; 1-5 settling section; 1-6 cone bottom; 1-7 horizontal smoke outlet;

[0038] A-gas phase inlet; B1~Bn liquid phase spray outlet; G1 first layer liquid phase spray outlet; G2 second layer liquid phase spray outlet; E-smoke outlet; F-sewage outlet;

[0039] L1 is the length of the reduced diameter section; L2 is the length of the throat diameter; L3 is the length of the expanded diameter section; L4 is the distance between the first layer liquid phase spray port G1 and the second layer liquid phase spray port G2;

[0040] θ - cone angle. DETAILED DESCRIPTION

[0041] The present invention is further explained in detail below with reference to the accompanying drawings and specific embodiments.

[0042] According to a preferred embodiment of the present invention, Figure 1 The figure shows a quenching purification device for sulfuric acid recovery, comprising a housing 1 of the device, and a flue gas inlet section 1-1, a diameter reduction section 1-2, a throat diameter 1-3, a diameter expansion section 1-4, and a sedimentation section 1-5 which are sequentially connected from top to bottom in the housing 1, wherein:

[0043] The flue gas inlet section 1-1 has a gas phase inlet 101 and is provided with a plurality of liquid phase spray ports, for allowing the scrubbing liquid to enter tangentially at a certain angle through the liquid phase spray ports;

[0044] The upper end of the diameter-reducing section 1-2 is connected to the flue gas inlet section 1-1. The diameter-reducing section 1-2 is configured as a tapered structure with a gradually decreasing radial dimension along the flue gas transmission direction, and is used to accelerate the flue gas and scrubbing liquid flowing into the flue gas inlet section 1-1.

[0045] The throat diameter 103 extends vertically downward along the bottom surface of the reduced diameter section 1-2, and is used to cool the flue gas, break up aerosols and absorb SO3;

[0046] The expanded diameter section 1-4 is connected to the bottom surface of the throat diameter 1-3. The expanded diameter section 1-4 is configured as a tapered structure with a gradually increasing radial dimension along the flue gas transmission direction. The expanded diameter section is provided with multiple layers of liquid phase spray ports. Each layer of liquid phase spray ports is provided with multiple atomizing nozzles spaced circumferentially, and the liquid phase spray ports of adjacent layers are staggered to further wash and cool the flue gas to a saturation temperature.

[0047] The sedimentation section 1-5 is extended along the lower end of the expansion section 1-4. The sedimentation section 1-5 has a cavity for accommodating the cooled flue gas and performing gas-liquid separation, and a horizontal flue gas outlet 1-7 is provided on its side wall. The horizontal flue gas outlet 1-7 is connected to the downstream equipment for further flue gas treatment.

[0048] Based on this embodiment, the high-temperature flue gas from the upstream waste heat recovery equipment enters the quenching purification device 1 for sulfuric acid recovery of the present invention from the gas phase inlet A from top to bottom. First, it enters the flue gas inlet section 1-1, and the circulating washing liquid passes through the liquid phase spray ports B1 to B n It enters the quenching purification device tangentially at a certain angle, forms a liquid film at the gas-liquid contact surface and provides the liquid phase evaporation required for quenching; it passes through the reduced diameter section 1-2 in sequence to reach the throat diameter 1-3. At the throat diameter 1-3, the gas phase flow rate is greatly increased, the gas kinetic energy is large, the gas and liquid are quickly mixed and turbulent is formed. Under the action of the drag force at the gas-liquid contact surface, the liquid phase is atomized to form small droplets, which collide and contact with the gas phase, thereby achieving the function of rapid cooling, washing and breaking the aerosol absorption of SO3 of this device, reducing the risk of subsequent equipment corrosion. Danger; then it reaches the expanded diameter section 1-4, and the liquid phase spray port G1 and the liquid phase spray port G2 atomize the liquid phase into small droplets at a certain spray angle and spray them into the rapid cooling purification device 1, and form a liquid phase coverage area at the lower end of the nozzle. In this area, the small liquid phase droplets further contact and collide with the gas phase to achieve deep rapid cooling and washing of the gas phase; the sedimentation section 1-5 is a cavity equipment, and the gas phase flow rate is relatively low. In this area, the gas phase passing through the throat diameter 1-3 and the expanded diameter section 1-4 carries part of the liquid phase through the effect of gravity sedimentation to achieve liquid-gas separation.

[0049] In order to improve the spraying effect, the multiple liquid phase spray ports B1 to B n The spray nozzles are arranged in a circular pattern on the same horizontal plane. In practical applications, the number n of spray nozzles is set to 3-8. The liquid spray nozzles are arranged at an angle of 15-75° along the tangent direction of the nozzles at the junction with the device. The flow rate of the spray liquid is closely related to the evaporation rate required to achieve saturation of the flue gas. To ensure the formation of a liquid film at the gas-liquid interface and the effectiveness of rapid cooling, scrubbing, and absorption of SO3 at the throat, the ratio of liquid spray volume to evaporation volume is 7-14, preferably 8-12.

[0050] In order to improve the coordination effect of each functional section of the device, the utility model has made various optimization settings respectively:

[0051] For the reduced diameter section 1-2:

[0052] The reduced diameter section 1-2 is located between the smoke inlet section 1-1 and the throat diameter 1-3, and has a structure that is wide at the top and narrow at the bottom. The upper end of the reduced diameter section 1-2 is connected to the smoke outlet section 1-1, and the lower end of the reduced diameter section 1-2 is connected to the throat diameter 1-3. The length L1 of the reduced diameter section 1-2 is 300 to 1200 mm. Based on this arrangement, the gradual acceleration of the smoke is promoted.

[0053] For throat diameters 1-3:

[0054] The length L2 of the throat diameter 1-3 is 200-1000 mm, and the gas phase velocity of the flue gas through the throat diameter 1-3 is 35-100 m / s, preferably 45-80 m / s. This allows the flue gas to quickly contact the scrubbing liquid flowing from the liquid phase spray port at the throat diameter 1-3, creating turbulent flow, breaking up aerosol-absorbed SO3, and cooling the flue gas.

[0055] For expansion sections 1-4:

[0056] The length L3 of the expanded diameter section 1-4 is 800 to 2000 mm, and its upper end is connected to the throat diameter 1-3. The liquid phase spray port of the expanded diameter section 1-4 is set to two layers, and the distance L4 between the two layers of liquid phase spray ports, i.e., the first layer of liquid phase spray port G1 and the second layer of liquid phase spray port G2, is 300 to 800 mm.

[0057] In order to improve the rapid cooling effect of the flue gas in the expansion sections 1-4, the atomizing nozzles in any layer of the liquid phase spray ports in the expansion sections 1-4 are uniformly spaced 3 to 8 along the circumferential direction; the two layers of liquid phase spray ports G1 / G2 are evenly staggered. The specific layout can be made according to actual needs. For example, in actual application, each layer of liquid phase spray ports is set to 6 according to needs, and the two adjacent atomizing nozzles in any layer of the liquid phase spray ports in the expansion sections 1-6 are arranged at an angle of 60°, and the two layers of liquid phase spray ports G1 / G2 are evenly staggered at an angle of 30°. More preferably, the liquid phase spray ports are tilted at an angle of 15-45° to the horizontal plane. The liquid phase is atomized into small droplets and enters at a certain spray angle. Based on this, the liquid phase spray density at 500-1000mm below the lower end of the lower layer of liquid phase spray ports can be controlled to be 40-120m 3 / (m 2 ·h). The preferred spray density is 50~90m 3 / (m 2 h), so that the flue gas is rapidly cooled to the saturation temperature, which is convenient for the subsequent gas-liquid separation.

[0058] For settling sections 1-5:

[0059] The upper end of the settling section 1-5 is connected to the expansion section 1-4. The upper wall of the horizontal flue gas outlet 1-7 is located below the liquid-phase coverage area formed by the expansion section 1-4. The lower wall of the horizontal flue gas outlet 1-7 is higher than the bottom surface of the settling section. Within this settling area, the gas phase passing through the throat 1-3 and the expansion section 1-4 entrains a portion of the liquid phase through gravity sedimentation, achieving liquid-gas separation. After the gas-liquid separation, the saturated flue gas flows toward the horizontal flue gas outlet 1-7 and enters subsequent equipment through the flue gas outlet E.

[0060] The lower side of the settling section 1-5 is also connected to a conical bottom. A drain port F is provided at the bottom of the conical bottom 1-6. Liquid and solids are discharged through the drain port F at the bottom of the settling section 1-5. The cone angle θ of the cone bottom 1-6 is 60 to 120 degrees. This cone angle facilitates the flow and discharge of solid dust washed from the liquid phase and reduces wall adhesion during the flow process.

[0061] Based on the above embodiments provided by the utility model, specific applications are as follows:

[0062] like Figure 1 As shown, the high-temperature flue gas from the sulfuric acid recovery unit, at a temperature of 350°C, enters flue gas inlet section 1-1 from top to bottom through gas inlet A. Circulating scrubbing liquid then flows tangentially into flue gas inlet section 1-1 at a specific angle through liquid spray ports B1-B6. The spray liquid flow rate is controlled at a ratio of 1:1 to the evaporation rate, ensuring the formation of a liquid film at the gas-liquid interface and the rapid cooling, scrubbing, and SO₃ absorption at throat diameter 1-3. The gas then carries the liquid into reduced diameter section 1-2, connected to flue gas inlet section 1-1. The reduced diameter section has a length of 700 mm. The flue gas gradually accelerates through reduced diameter section 1-2, reaching a velocity of 54 m / s at throat diameter 1-3, which has a length of 650 mm. At throat diameter 1-3, the flue gas rapidly contacts the scrubbing liquid flowing from liquid spray ports B1-B6, creating turbulent flow that breaks up aerosols, absorbs SO₃, and reduces the flue gas temperature to below 90°C. Then it enters the expansion section 1-4, and further contacts and collides with the liquid droplets sprayed from the atomizing nozzles of the first layer of liquid phase spray port G1 and the second layer of liquid phase spray port G2, achieving deep rapid cooling and washing of the gas phase. The spacing L4 between the two layers of liquid phase spray ports is 550mm. The atomizing nozzles of the two layers of liquid phase spray ports atomize the liquid phase into small droplets at a certain spray angle and spray them into the housing 1 of the device of the utility model, and form a liquid phase coverage area below the atomizing nozzle. The liquid phase spray density at 500-1000mm below the lower layer of atomizing nozzle reaches 50-83m 3 / (m 2h), at which point the flue gas is rapidly cooled to a saturation temperature of approximately 84°C. The cooled flue gas then carries some liquid, undergoing gas-liquid separation in the settling section 1-5. The gas phase then enters the subsequent equipment through the horizontal flue gas outlet 1-7, while the liquid phase and solids are discharged from the bottom of the settling section 1-5 through the drain outlet F of the cone bottom 1-6, which has a cone angle θ of 100°.

[0063] The above embodiments are only used to further illustrate the technical solution of the present invention in detail and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by technicians in this field based on the above content of the present invention are all within the scope of protection of the present invention.

Claims

1. A quenching purification device for sulfuric acid recovery, characterized in that: It includes a flue gas inlet section, a diameter reduction section, a throat diameter section, a diameter expansion section, and a sedimentation section which are sequentially connected from top to bottom, wherein: The flue gas inlet section has a gas phase inlet and is provided with a plurality of liquid phase spray ports; The upper end of the diameter-reducing section is connected to the smoke inlet section, and the radial dimension of the diameter-reducing section along the smoke transmission direction gradually decreases; The throat diameter is vertically extended downward along the lower end of the reduced diameter section; The upper end of the expanded diameter section is connected to the lower end of the throat diameter, and the radial diameter of the expanded diameter section gradually increases along the flue gas transmission direction. The expanded diameter section is provided with multiple layers of liquid phase spray ports, each layer of liquid phase spray ports is arranged with multiple atomizing nozzles at intervals along the circumferential direction, and the liquid phase spray ports of two adjacent layers are staggered. The settling section is extended along the lower end of the diameter-expanding section and has a cavity for accommodating cooled flue gas and performing gas-liquid separation; and a horizontal flue gas outlet is provided on the side wall of the settling section.

2. The quenching and purification device for sulfuric acid recovery according to claim 1, characterized in that: The multiple liquid phase spray ports provided in the flue gas inlet section are distributed in a ring shape on the same horizontal plane, and the number of the liquid phase spray ports is 3 to 8; the liquid phase spray ports are arranged at an angle of 15-75 degrees along the tangent direction of the connection between the liquid phase spray ports and the device.

3. The rapid cooling and purification device for sulfuric acid recovery according to claim 1, characterized in that: The length L1 of the diameter-reduced section is 300-1200 mm.

4. The rapid cooling and purification device for sulfuric acid recovery according to claim 1, characterized in that: The length L2 of the throat diameter is 200-1000 mm, and the gas phase flow rate of the flue gas through the throat diameter is 35-100 m / s.

5. The rapid cooling and purification device for sulfuric acid recovery according to claim 1, characterized in that: The length L3 of the diameter expansion section is 800 to 2000 mm.

6. The rapid cooling and purification device for sulfuric acid recovery according to claim 5, characterized in that: The liquid phase spraying openings of the diameter expansion section are arranged in two layers, upper and lower, and the distance L4 between the two layers of liquid phase spraying openings is 300 to 800 mm.

7. The rapid cooling and purification device for sulfuric acid recovery according to claim 6, characterized in that: The atomizing nozzles in any layer of liquid phase spray openings in the diameter expansion section are uniformly spaced and arranged in 3 to 8 numbers along the circumferential direction; the two layers of liquid phase spray openings are uniformly staggered.

8. The quenching and purification device for sulfuric acid recovery according to any one of claims 5 to 7, characterized in that: The liquid phase spraying port of the expansion section is inclined at 15-45 degrees to the horizontal plane, and the liquid phase spraying density at 500-1000 mm below the lower end of the lower liquid phase spraying port is controlled to be 40-120 m 3 / (m 2 ·h).

9. The rapid cooling and purification device for sulfuric acid recovery according to claim 1, characterized in that: The upper wall of the horizontal smoke outlet is located at the lower end of the liquid phase coverage area formed by the diameter expansion section; the lower wall of the horizontal smoke outlet is higher than the bottom surface of the sedimentation section.

10. The rapid cooling and purification device for sulfuric acid recovery according to claim 1, characterized in that: The lower side of the sedimentation section is further connected to a cone bottom, and a sewage outlet is provided at the bottom of the cone bottom; and the cone angle θ of the cone bottom is 60 to 120 degrees.

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