A spent sulfuric acid purification and concentration treatment system and a process for using the same

Abstract

A waste sulfuric acid purification and concentration treatment system includes an ion exchange device comprising a set of reaction towers filled with ion exchange resin, an acid washing tank, an acid washing pump, a water washing tank, and a water washing pump. The acid washing tank is connected to a regeneration pipeline via pipes and the acid washing pump, and the water washing tank is connected to the regeneration pipeline via pipes and the water washing pump. The end of the regeneration pipeline is connected to the bottom of the set of reaction towers. A membrane distillation device includes a raw material tank, a thin-film evaporator, a flash evaporator, a vacuum pump, a circulating water tank, a cooler, a cold circulation mechanism, and a hot circulation mechanism. This invention removes ferrous and calcium ions from waste sulfuric acid through ion exchange and membrane distillation. Under low-temperature negative pressure conditions, multi-stage treatment via membrane distillation and flash evaporator enables the concentration and reuse of waste sulfuric acid. The treatment system of this invention features mild reaction conditions, simple operation, and high separation efficiency, exhibiting excellent economic benefits and promising application prospects.

Description

Technical Field

[0001] This invention relates to the field of waste acid treatment technology, specifically to a waste sulfuric acid purification and concentration treatment system and its application process. Background Technology

[0002] Sulfuric acid, as one of the important basic raw materials in the chemical industry, is widely used in petrochemical, steel, metallurgy, pharmaceutical and other fields. During the production and use of sulfuric acid, a large amount of by-product waste acid is generated. This waste acid has a low concentration and contains impurities such as ferrous ions, which cannot be effectively utilized. Direct discharge will not only cause serious damage to the environment, but also waste resources.

[0003] The main traditional method for treating waste sulfuric acid is neutralization, which involves adding liquid alkali to neutralize it before discharge. This method wastes a large amount of acid and alkali resources and has high treatment costs. Alternatively, lime can be added for neutralization, but this generates a large amount of sludge, causing secondary pollution. Therefore, the resource-based treatment and reuse of waste sulfuric acid is of great significance to both the economy and the environment.

[0004] Membrane distillation is a novel separation technology that combines membrane separation with distillation. It utilizes the vapor pressure difference across the membrane as the driving force and leverages the membrane's hydrophobic properties to allow water vapor to permeate through the membrane and condense on the low-pressure side, thus achieving separation and concentration. It offers advantages such as mild reaction conditions, simple operation, high separation efficiency, and stable processing results. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in current waste sulfuric acid treatment technologies by providing a waste sulfuric acid purification and concentration system that can solve the problems of effective waste sulfuric acid treatment, environmental impact, and resource waste. Another purpose of this invention is to provide a treatment method for the waste sulfuric acid purification and concentration system, enabling the purification and concentration of waste sulfuric acid for reuse.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0007] A waste sulfuric acid purification and concentration treatment system, including

[0008] An ion exchange device includes a set of reaction towers filled with ion exchange resin, an acid washing tank, an acid washing pump, a water washing tank, and a water washing pump. The acid washing tank is connected to a regeneration pipeline via a pipe and the acid washing pump. The water washing tank is connected to the regeneration pipeline via a pipe and the water washing pump. The end of the regeneration pipeline is connected to the bottom of the set of reaction towers.

[0009] A membrane distillation device includes a feed tank, a thin-film evaporator, a flash tower, a vacuum pump, a circulating water tank, a cooler, a cold circulation mechanism, and a hot circulation mechanism. The feed tank is connected to the bottom outlet of a set of reaction towers through a purified water outlet pipe, and the feed tank is connected to the thin-film evaporator and the flash tower through a discharge pipe.

[0010] The thin-film evaporator includes a membrane evaporation component and a membrane condensation component, which are respectively connected to a flash tower and a cold circulation mechanism. The flash tower is connected to a hot circulation mechanism. The inlet of the vacuum pump is connected to the outlet of the membrane condensation component via a pipe. The outlet of the circulating water tank is connected to the sealing liquid interface of the vacuum pump via a pipe. The outlet of the vacuum pump is connected to the cooler via a pipe. The outlet of the cooler is connected to the circulating water tank via a pipe.

[0011] The cooling circulation mechanism includes a cooling water inlet pipe and a cooling water return pipe. The cooling water inlet pipe is connected to the medium inlet of the membrane condensation module and the cooler, respectively, and the cooling water return pipe is connected to the medium outlet of the membrane condensation module and the heat exchanger.

[0012] The heat circulation mechanism includes a heat circulation heat exchanger, a heat circulation pump, a pressure-reducing steam pipeline, and a condensate pipeline. The bottom heat circulation outlet of the flash tower is connected to the heat circulation pump and the heat circulation heat exchanger in sequence through pipelines. The outlet of the heat circulation heat exchanger is connected back to the heat circulation inlet of the flash tower through pipelines. The medium inlet and medium outlet of the heat circulation heat exchanger are respectively connected to the pressure-reducing steam pipeline and the condensate pipeline.

[0013] Preferably, the regeneration pipeline is connected to the factory air duct, the top of the reaction tower is connected to the feed pipeline and the regeneration eluent pipeline, and the bottom of the reaction tower is connected to the raw material tank through the purified water outlet pipeline.

[0014] Preferably, the feed control solenoid valves are installed on the discharge pipes connecting the raw material tank to the membrane evaporation unit and the flash tower.

[0015] Preferably, the concentrate outlet at the bottom of the membrane evaporation unit is connected to the feed tank via a concentrate pipe, and the bottom of the membrane condensation unit is connected to an evaporation condensate discharge pipe.

[0016] Preferably, the concentrated acid outlet at the bottom of the flash tower is connected to an external discharge pump via a pipeline. The discharge pipe of the external discharge pump is equipped with an online sulfuric acid concentration meter and a pair of solenoid valves to control the discharge of concentrated acid for reuse or return to the raw material tank.

[0017] A process for using a waste sulfuric acid purification and concentration treatment system includes the following steps:

[0018] Waste sulfuric acid is passed through a reaction tower and reacts with the ion exchange resin inside to remove iron and calcium ions. The purified waste sulfuric acid enters the raw material tank. After the ion exchange resin is saturated, it is regenerated by alternating acid washing and water washing. The eluent is discharged through the regenerated eluent pipeline after neutralization treatment.

[0019] The thin-film evaporator is kept under negative pressure by a vacuum pump. Waste sulfuric acid in the raw material tank is drawn into the membrane evaporation unit and flash tower under negative pressure. The concentrate in the membrane evaporation unit is returned to the raw material tank through the concentrate pipeline. The water vapor after vaporization in the membrane evaporation unit enters the membrane condensation unit through the distillation membrane and the water vapor after vaporization in the flash tower. They are condensed under the action of the cold circulation mechanism. The evaporation condensate is discharged through the evaporation condensate discharge pipeline. The flash tower is fed intermittently. The concentrated acid after concentration is discharged through the external discharge pump. The external discharge is controlled by an online sulfuric acid concentration meter for reuse or return to the raw material tank.

[0020] Cooling water inlet passes through membrane condenser and cooler and is then discharged through cooling water return pipe. Vacuum pump is water ring vacuum pump, which achieves cooling through cooler and circulating water tank.

[0021] The depressurized steam is discharged through the condensate pipe after passing through the heat exchanger. The waste sulfuric acid in the flash tower is heated by the heat exchanger and the heat pump. The vacuum pump draws the water vapor after vaporization in the flash tower through the membrane evaporation module and then into the membrane condensation module to heat the membrane evaporation module.

[0022] Preferably, there are two reaction towers in a set, which are operated alternately for regeneration; the ion exchange resin is a cation exchange resin containing sulfonic acid groups; the pickling solution in the pickling tank is low-concentration sulfuric acid; and the water washing tank contains softened water.

[0023] Preferably, the vacuum level inside the thin-film evaporator is controlled at 100-150 mbar.

[0024] Preferably, the heating temperature of waste sulfuric acid in the flash evaporator is controlled at 65-75℃.

[0025] Preferably, the waste sulfuric acid feed concentration is 2%-8%, the ferrous ion concentration after purification is ≤1mg / L, the sulfuric acid concentration after concentration is >40%, and the concentration ratio is 5-20 times.

[0026] The advantages of this invention are:

[0027] 1. This invention removes ferrous and calcium ions from waste sulfuric acid through ion exchange and membrane distillation. Under low temperature and negative pressure conditions, the waste sulfuric acid is concentrated and reused through multi-stage treatment by membrane distillation and flash tower. The treatment system of this invention has mild reaction conditions, simple operation, and high separation efficiency, and has very good economic benefits and application prospects.

[0028] 2. The system of this invention can achieve fully automated operation and can flexibly adjust operating parameters according to feed concentration and product requirements. Through online monitoring and control of sulfuric acid concentration, it ensures stable waste sulfuric acid treatment effect. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0032] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] In the description of the embodiments of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, they are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, if terms such as "first" or "second" appear in the description of this invention, they are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0034] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0035] like Figure 1 As shown, a waste sulfuric acid purification and concentration treatment system includes...

[0036] An ion exchange device includes a set of reaction towers 2 filled with ion exchange resin, an acid washing tank 7, an acid washing pump 8, a water washing tank 9 and a water washing pump 10. The acid washing tank 7 is connected to a regeneration pipeline through a pipe and the acid washing pump 8. The water washing tank 9 is connected to a regeneration pipeline through a pipe and the water washing pump 10. The end of the regeneration pipeline is connected to the bottom of the set of reaction towers 2.

[0037] The membrane distillation equipment includes a raw material tank 11, a thin film evaporator 12, a flash tower 22, a vacuum pump 17, a circulating water tank 16, a cooler 15, a cold circulation mechanism, and a hot circulation mechanism. The raw material tank 11 is connected to the bottom outlet of a set of reaction towers 2 through a purified water outlet pipe 4. The raw material tank 11 is connected to the thin film evaporator 12 and the flash tower 22 through a discharge pipe.

[0038] The thin-film evaporator 12 includes a membrane evaporation assembly 13 and a membrane condensation assembly 14. The membrane evaporation assembly 13 and the membrane condensation assembly 14 are respectively connected to the flash tower 22 and the cold circulation mechanism. The flash tower 22 is connected to the hot circulation mechanism. The inlet of the vacuum pump 17 is connected to the outlet of the membrane condensation assembly 14 through a pipe. The outlet of the circulating water tank 16 is connected to the sealing liquid interface of the vacuum pump 17 through a pipe. The outlet of the vacuum pump 17 is connected to the cooler 15 through a pipe. The outlet of the cooler 15 is connected to the circulating water tank 16 through a pipe.

[0039] The cooling circulation mechanism includes a cooling water inlet pipe 18 and a cooling water return pipe 19. The cooling water inlet pipe 18 is connected to the medium inlet of the membrane condensation module 14 and the cooler 15, respectively, and the cooling water return pipe 19 is connected to the medium outlet of the membrane condensation module 14 and the heat exchanger 15.

[0040] The heat circulation mechanism includes a heat circulation heat exchanger 23, a heat circulation pump 24, a pressure-reducing steam pipe 25, and a condensate pipe 26. The bottom heat circulation outlet of the flash tower 22 is connected to the heat circulation pump 24 and the heat circulation heat exchanger 23 in sequence through pipes. The outlet of the heat circulation heat exchanger 23 is connected back to the heat circulation inlet of the flash tower 22 through pipes. The medium inlet and medium outlet of the heat circulation heat exchanger 23 are respectively connected to the pressure-reducing steam pipe 25 and the condensate pipe 26.

[0041] The regeneration pipeline is also connected to the factory air duct 6, the top of the reaction tower 2 is connected to the feed pipeline 1 and the regeneration eluent pipeline 5, and the bottom of the reaction tower 2 is connected to the raw material tank 11 through the purified water outlet pipeline 4.

[0042] Solenoid valves for controlling the feed are installed on the discharge pipes that connect the raw material tank 11 to the membrane evaporation unit 13 and the flash tower 22.

[0043] The concentrate outlet at the bottom of the membrane evaporation unit 13 is connected to the raw material tank 11 via the concentrate pipe 21, and the bottom of the membrane condensation unit 14 is connected to the evaporation condensate discharge pipe 20.

[0044] The concentrated acid outlet at the bottom of the flash distillation tower 22 is connected to the discharge pump 27 via a pipeline. The discharge pipe 28 of the discharge pump 27 is equipped with an online sulfuric acid concentration meter 29 and a pair of solenoid valves to control the discharge of concentrated acid for reuse or return to the raw material tank 11. The circulating water tank 16 is an open-top tank to facilitate overflow when full.

[0045] A process for using a waste sulfuric acid purification and concentration treatment system includes the following steps:

[0046] Waste sulfuric acid passes through reaction tower 2 and reacts with ion exchange resin 3 inside to remove iron and calcium ions and impurities. The purified waste sulfuric acid enters raw material tank 11. After the ion exchange resin 3 is saturated, it is regenerated by alternating acid washing and water washing. The eluent is discharged through regenerated eluent pipeline 5 after neutralization treatment.

[0047] The vacuum pump 17 maintains a negative pressure state in the thin film evaporator. Waste sulfuric acid in the raw material tank 11 is drawn into the membrane evaporation component 13 and flash tower 22 under negative pressure. The concentrate of the membrane evaporation component 13 is returned to the raw material tank 11 through the concentrate pipe 21. The water vapor after vaporization in the membrane evaporation component 13 and the water vapor after vaporization in the flash tower 22 both enter the membrane condensation component 14 and are condensed under the action of the cold circulation mechanism. The evaporated condensate is discharged through the evaporated condensate discharge pipe 20. The flash tower 22 is intermittently fed. The concentrated acid after concentration is discharged through the external discharge pump 27. The external discharge is controlled by the online sulfuric acid concentration meter 29 for reuse or return to the raw material tank 11.

[0048] The cooling water inlet pipe 18 passes through the membrane condenser assembly 14 and the cooler 15 and is discharged through the cooling water return pipe 19. The vacuum pump 17 is a water ring vacuum pump, which achieves cooling through the cooler 15 and the circulating water tank 16.

[0049] After passing through the heat exchanger 23, the depressurized steam is discharged through the condensate pipe 26. The waste sulfuric acid in the flash tower 22 is heated by the heat exchanger 23 and the heat pump 24. The vacuum pump 17 draws the water vapor after it is vaporized in the flash tower 22, passes through the membrane evaporation component 13, and enters the membrane condensation component 14 to heat the membrane evaporation component 13.

[0050] There are two reaction towers 2 in a set, which are operated alternately for regeneration; the ion exchange resin 3 is a cation exchange resin containing sulfonic acid groups; the pickling solution in the pickling tank 7 is low-concentration sulfuric acid; and the water washing tank 9 contains softened water.

[0051] The vacuum level inside the thin-film evaporator 12 is controlled at 100-150 mbar.

[0052] The temperature of waste sulfuric acid heating inside flash evaporator 22 is controlled at 65-75℃.

[0053] The feed concentration of waste sulfuric acid is 2%-8%, the ferrous ion concentration after purification is ≤1mg / L, the sulfuric acid concentration after concentration is >40%, and the concentration ratio is 5-20 times.

[0054] Example 1

[0055] A sulfuric acid production unit at a refinery in Hubei province is producing 24 cubic meters of waste sulfuric acid as a byproduct. 3 / day, waste sulfuric acid concentration 5%-8%, ferrous ion ≥10mg / L, calcium ion ≥10mg / L, treated using the treatment system and method described above in this invention, the treatment process includes:

[0056] Waste sulfuric acid at a rate of 1 m³ / h is treated by ion exchange in a reaction tower. After purification, the ferrous ion concentration in the waste sulfuric acid is <1 mg / L and the calcium ion concentration is <1 mg / L. The purified waste sulfuric acid then enters the raw material tank.

[0057] The temperature of the thin-film evaporator is 72℃, the vacuum degree is 110mbar, and the temperature difference between the inlet and outlet cooling water of the membrane condenser is maintained at >1℃. Waste acid from the feed tank enters the membrane evaporation unit under negative pressure. After membrane evaporation treatment, the concentrated water is returned to the feed tank. At the same time, waste acid from the feed tank is intermittently drawn into the flash evaporator for evaporation treatment. The control conditions are that the flash evaporator is fed at a low liquid level and stops feeding at a high liquid level. The concentration of waste acid in the feed tank is 18%-25%.

[0058] The concentration of acid produced in the flash evaporator is controlled by adjusting the liquid level parameters. After concentration, the sulfuric acid is discharged through an external pump. The control conditions are that the external pump is started when the liquid level in the flash evaporator is high and stopped when the liquid level is low. The concentration of sulfuric acid after concentration is >40%, and the concentration ratio is 5-8 times.

[0059] Example 2

[0060] A chemical plant has 48m³ of waste sulfuric acid containing ferrous and calcium ions as impurities. 3 / day, waste sulfuric acid concentration 2%-8%, ferrous ion ≥5mg / L;

[0061] The temperature of the thin-film evaporator is 69°C, the vacuum degree is 100mbar, and the processing procedure is similar to that in Example 1. After being processed by the above-described processing system and method, the ferrous ion concentration in the purified and concentrated sulfuric acid is <1mg / L, the sulfuric acid concentration is >40%, and the concentration factor is 5-20 times.

[0062] The above embodiments are only for illustrating the technical solutions and features of the present invention, and are intended to enable those skilled in the art to implement them better. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention are within the scope of protection of the present invention. The parts not described in detail are prior art.

Claims

1. A waste sulfuric acid purification and concentration treatment system, characterized in that... include An ion exchange device includes a set of reaction towers (2) filled with ion exchange resin, an acid washing tank (7), an acid washing pump (8), a water washing tank (9) and a water washing pump (10), wherein the acid washing tank (7) is connected to a regeneration pipeline via a pipe and the acid washing pump (8), and the water washing tank (9) is connected to a regeneration pipeline via a pipe and the water washing pump (10), and the end of the regeneration pipeline is connected to the bottom of the set of reaction towers (2); The membrane distillation equipment includes a raw material tank (11), a thin film evaporator (12), a flash distillation tower (22), a vacuum pump (17), a circulating water tank (16), a cooler (15), a cold circulation mechanism, and a hot circulation mechanism. The raw material tank (11) is connected to the bottom outlet of a set of reaction towers (2) through a purified water outlet pipe (4). The raw material tank (11) is connected to the thin film evaporator (12) and the flash distillation tower (22) through a discharge pipe. The thin-film evaporator (12) includes a membrane evaporation assembly (13) and a membrane condensation assembly (14). The membrane evaporation assembly (13) and the membrane condensation assembly (14) are respectively connected to the flash tower (22) and the cold circulation mechanism. The flash tower (22) is connected to the hot circulation mechanism. The inlet of the vacuum pump (17) is connected to the outlet of the membrane condensation assembly (14) through a pipe. The outlet of the circulating water tank (16) is connected to the sealing liquid interface of the vacuum pump (17) through a pipe. The outlet of the vacuum pump (17) is connected to the cooler (15) through a pipe. The outlet of the cooler (15) is connected to the circulating water tank (16) through a pipe. The cooling circulation mechanism includes a cooling water inlet pipe (18) and a cooling water return pipe (19). The cooling water inlet pipe (18) is connected to the medium inlet of the membrane condensation module (14) and the cooler (15) respectively, and the cooling water return pipe (19) is connected to the medium outlet of the membrane condensation module (14) and the heat exchanger (15). The heat circulation mechanism includes a heat circulation heat exchanger (23), a heat circulation pump (24), a pressure-reducing steam pipe (25), and a condensate pipe (26). The bottom heat circulation outlet of the flash tower (22) is connected to the heat circulation pump (24) and the heat circulation heat exchanger (23) in sequence through pipes. The outlet of the heat circulation heat exchanger (23) is connected back to the heat circulation inlet of the flash tower (22) through pipes. The medium inlet and medium outlet of the heat circulation heat exchanger (23) are respectively connected to the pressure-reducing steam pipe (25) and the condensate pipe (26). The regeneration pipeline is connected to the factory air duct (6) at the same time. The top of the reaction tower (2) is connected to the feed pipeline (1) and the regeneration eluent pipeline (5). The bottom of the reaction tower (2) is connected to the raw material tank (11) through the purified water outlet pipeline (4). The feed pipes connecting the raw material tank (11) to the membrane evaporation unit (13) and the flash tower (22) are all equipped with solenoid valves to control the feed. The concentrate outlet at the bottom of the membrane evaporation unit (13) is connected to the raw material tank (11) through the concentrate pipe (21), and the bottom of the membrane condensation unit (14) is connected to the evaporation condensate discharge pipe (20). The concentrated acid outlet at the bottom of the flash tower (22) is connected to the external discharge pump (27) via a pipeline. The discharge pipe (28) of the external discharge pump (27) is equipped with an online sulfuric acid concentration meter (29) and a pair of solenoid valves to control the discharge of concentrated acid for reuse or return to the raw material tank (11).

2. The process of using the waste sulfuric acid purification and concentration treatment system according to claim 1, characterized in that, Includes the following steps: Waste sulfuric acid is passed through a reaction tower (2) and reacts with the ion exchange resin (3) installed inside to remove iron ions and calcium ions impurities from the waste sulfuric acid. The purified waste sulfuric acid enters the raw material tank (11). After the ion exchange resin (3) is saturated, it is regenerated by alternating acid washing and water washing. The eluent is discharged through the regenerated eluent pipeline (5) and discharged after neutralization treatment. The vacuum pump (17) maintains the negative pressure state of the thin film evaporator. The waste sulfuric acid in the raw material tank (11) is drawn into the membrane evaporation component (13) and the flash tower (22) under the action of negative pressure. The concentrate of the membrane evaporation component (13) is returned to the raw material tank (11) through the concentrate pipe (21). The water vapor after vaporization of the membrane evaporation component (13) enters the membrane condensation component (14) through the distillation membrane and the water vapor after vaporization of the flash tower (22). It is condensed under the action of the cold circulation mechanism. The evaporated condensate is discharged through the evaporated condensate discharge pipe (20). The flash tower (22) is intermittently fed. The concentrated acid after concentration is discharged through the external discharge pump (27). The external discharge is controlled by the online sulfuric acid concentration meter (29) for reuse or return to the raw material tank (11). The cooling water inlet pipe (18) passes through the membrane condenser assembly (14) and the cooler (15) and is discharged through the cooling water return pipe (19). The vacuum pump (17) is a water ring vacuum pump, which achieves cooling through the cooler (15) and the circulating water tank (16). The depressurized steam is discharged through the condensate pipe (26) after passing through the heat exchanger (23). The waste sulfuric acid in the flash tower (22) is heated by the heat exchanger (23) and the heat pump (24). The vacuum pump (17) draws the water vapor after the flash tower (22) is vaporized and enters the membrane condensation assembly (14) after passing through the membrane evaporation assembly (13), thereby heating the membrane evaporation assembly (13).

3. The process of using the waste sulfuric acid purification and concentration treatment system according to claim 2, characterized in that, There are two reaction towers (2) in a set, which are operated alternately for regeneration; the ion exchange resin (3) is a cation exchange resin containing sulfonic acid acid groups; the pickling solution in the pickling tank (7) is low-concentration sulfuric acid; and the water washing tank (9) contains softened water.

4. The process of using the waste sulfuric acid purification and concentration treatment system according to claim 2, characterized in that, The vacuum level inside the thin-film evaporator (12) is controlled at 100-150 mbar.

5. The process of using the waste sulfuric acid purification and concentration treatment system according to claim 2, characterized in that, The temperature of waste sulfuric acid in the flash tower (22) is controlled at 65-75℃.

6. The process of using the waste sulfuric acid purification and concentration treatment system according to claim 2, characterized in that, The feed concentration of waste sulfuric acid is 2%-8%, the ferrous ion concentration after purification is ≤1mg / L, the sulfuric acid concentration after concentration is >40%, and the concentration ratio is 5-20 times.

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