Dilute sulfuric acid concentration device

Abstract

According to the dilute sulphuric acid concentration device, the first heat exchanger is arranged to preheat dilute sulphuric acid through waste heat of concentrated sulphuric acid output by the concentration kettle, meanwhile, the vacuum unit is arranged to vacuumize the concentration kettle so as to reduce the concentration temperature, and steam evaporated by concentration of the dilute sulphuric acid in the concentration kettle is pumped out by the vacuum unit and condensed in the condenser; and recycling in a wastewater tank. And the concentrated sulfuric acid subjected to heat exchange and cooling by the first heat exchanger is input into the concentrated sulfuric acid treatment device to be recycled. According to the device disclosed by the invention, dilute sulphuric acid is concentrated and then recovered through cooperative use of the devices, so that the defect that resources are wasted due to the fact that dilute sulphuric acid generated in the chlor-alkali industry is difficult to recycle is overcome.

Description

Technical Field

[0001] The present application relates to the technical field of material concentration, and in particular to a device for concentrating dilute sulfuric acid. Background Art

[0002] Sulfuric acid is one of the important basic chemical raw materials and the most important product in the chemical industry. It is mainly used to manufacture inorganic chemical fertilizers. Secondly, it is used as a basic chemical raw material in the smelting of non-ferrous metals, petroleum refining and petrochemicals, textile printing and dyeing, inorganic salt industry, certain inorganic acids and organic acids, rubber industry, paint industry, as well as national defense and military industry, pesticides and medicines, leather making, coking and other industrial sectors. In addition, it is also used for steel pickling.

[0003] In the chlor-alkali industry, concentrated sulfuric acid is needed to dry the gas in processes such as drying chlorine. In this process, concentrated sulfuric acid absorbs water to produce low-concentration dilute sulfuric acid, also known as waste sulfuric acid. Since these sulfuric acids contain a large amount of water and are mixed with a small amount of chlorine and other substances, the secondary utilization range of these waste sulfuric acids is narrow. The amount of waste sulfuric acid generated by the factory is large, but the amount consumed for secondary utilization is relatively small. This results in a large amount of waste sulfuric acid being stored in the factory and difficult to be processed. The storage of waste sulfuric acid not only takes up a lot of space, but is also difficult to use, resulting in a waste of resources. Utility Model Content

[0004] The present application provides a dilute sulfuric acid concentration device to solve the problem that the dilute sulfuric acid produced in the above-mentioned chlor-alkali industry is difficult to recycle and reuse, resulting in waste of resources.

[0005] The present application provides a dilute sulfuric acid concentration device, comprising a dilute sulfuric acid storage tank, a first heat exchanger, a concentration kettle, a condenser, a vacuum unit and a tail gas treatment device connected in series in sequence;

[0006] The dilute sulfuric acid storage tank is connected to the tube side input end of the first heat exchanger, the tube side output end of the first heat exchanger is connected to the material input end of the concentration kettle, the material output end of the concentration kettle is connected to the shell side input end of the first heat exchanger, and the shell side output end of the first heat exchanger is connected to the concentrated sulfuric acid processing device;

[0007] The gas output end of the concentration kettle is connected to the condenser;

[0008] The vacuum unit is also connected to the steam line;

[0009] The vacuum unit and condenser are both connected to the waste water tank.

[0010] Optionally, a filtering device is further provided between the dilute sulfuric acid storage tank and the first heat exchanger.

[0011] Optionally, a dilute acid washing tower is provided between the first heat exchanger and the concentrating kettle;

[0012] The tube side output end of the first heat exchanger is connected to the material input end of the dilute acid washing tower, and the material output end of the dilute acid washing tower is connected to the material input end of the concentration kettle;

[0013] The gas output end of the concentration kettle is connected to the gas input end of the dilute acid washing tower, and the gas output end of the dilute acid washing tower is connected to the condenser.

[0014] Optionally, the concentrated sulfuric acid treatment device comprises an intermediate storage tank, a second heat exchanger and a concentrated acid storage tank connected in series;

[0015] The intermediate storage tank is connected to the shell side output end of the first heat exchanger.

[0016] Optionally, the tail gas treatment device includes a tail gas absorption tower and an incinerator connected in series.

[0017] Optionally, a first activated carbon layer, a basic alumina layer and a second activated carbon layer are sequentially arranged in the tail gas absorption tower along the gas flow direction.

[0018] Optionally, the filtering device comprises a horizontally arranged housing, the housing is divided into a first filter chamber and a second filter chamber on one side by a vertically arranged partition, and the housings of the first filter chamber and the second filter chamber are respectively closed by a first end cap and a second end cap;

[0019] A first filter cavity is provided with multiple layers of coaxially arranged barrel-shaped first filter screens, the closed end of the first filter screen is close to the partition plate, and the open end is connected to the first end cover;

[0020] The first end cover is respectively provided with a first liquid inlet and a first backflushing liquid outlet; the side surface of the shell body where the first filter cavity is located is respectively provided with a first liquid outlet and a first backflushing liquid inlet.

[0021] Optionally, a plurality of coaxially arranged barrel-shaped second filter screens are provided in the second filter cavity, the closed end of the second filter screen is close to the partition plate, and the open end is connected to the second end cover;

[0022] The second end cover is provided with a second liquid inlet and a second backwash liquid outlet; the side of the housing where the second filter cavity is located is provided with a second liquid outlet and a second backwash liquid inlet;

[0023] The first liquid inlet and the second liquid inlet are respectively connected to the dilute sulfuric acid storage tank through a first three-way valve;

[0024] The first liquid outlet and the second liquid outlet are respectively connected to the pipe side inlet of the first heat exchanger through a second three-way valve;

[0025] The first backflushing liquid inlet and the second backflushing liquid inlet are connected via a control valve.

[0026] The present application provides a dilute sulfuric acid concentration device, which preheats the dilute sulfuric acid by using the waste heat of the concentrated sulfuric acid output from the concentration kettle through the first heat exchanger, and simultaneously evacuates the concentration kettle to reduce the concentration temperature. The steam evaporated by the concentration of the dilute sulfuric acid in the concentration kettle is extracted by the vacuum unit, condensed in the condenser, and recovered in the wastewater tank. The concentrated sulfuric acid after heat exchange and temperature reduction by the first heat exchanger is input into the concentrated sulfuric acid treatment device for recovery. The device of the present application recovers the dilute sulfuric acid after concentration through the coordinated use of the above-mentioned devices, thereby overcoming the drawback that the dilute sulfuric acid produced in the chlor-alkali industry is difficult to recycle and thus leads to waste of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 A schematic diagram of a dilute sulfuric acid concentration device provided in one embodiment of the present application;

[0029] Figure 2 A schematic diagram of a dilute sulfuric acid concentration device provided in another embodiment of the present application;

[0030] Figure 3 A schematic diagram of a dilute sulfuric acid concentration device provided in yet another embodiment of the present application;

[0031] Figure 4 A schematic diagram of a dilute sulfuric acid concentration device provided in yet another embodiment of the present application;

[0032] Figure 5 A schematic diagram of a dilute sulfuric acid concentration device provided in one embodiment of the present application;

[0033] Figure 6 A schematic diagram of the structure of a tail gas absorption tower provided in one embodiment of the present application;

[0034] Figure 7 A schematic diagram of the structure of a filtering device provided in one embodiment of the present application.

[0035] Description of reference numerals:

[0036] 1. Dilute sulfuric acid storage tank; 2. First heat exchanger; 3. Concentrator; 4. Condenser; 5. Tail gas treatment device; 6. Concentrated sulfuric acid treatment device; 7. Filter device; 8. Dilute acid washing tower; 41. Vacuum unit; 42. Steam pipeline; 43. Wastewater tank; 51. Tail gas absorption tower; 52. Incinerator; 61. Intermediate storage tank; 62. Second heat exchanger; 63. Concentrated acid storage tank; 70. Shell; 71. First filter screen; 72. Second filter screen; 73. Partition; 100. First three-way valve ; 200, second three-way valve; 300, control valve; 511, first activated carbon layer; 512, alkaline alumina layer; 513, second activated carbon layer; 701, first end cover; 702, second end cover; 7101, first liquid inlet; 7102, first backflushing liquid outlet; 7103, first liquid outlet; 7104, first backflushing liquid inlet; 7201, second liquid inlet; 7202, second backflushing liquid outlet; 7203, second liquid outlet; 7204, second backflushing liquid inlet. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.

[0038] like Figure 1 As shown, the present application provides a dilute sulfuric acid concentration device, comprising a dilute sulfuric acid storage tank 1, a first heat exchanger 2, a concentration kettle 3, a condenser 4, a vacuum unit 41 and a tail gas treatment device 5 connected in series in sequence;

[0039] The dilute sulfuric acid storage tank 1 is connected to the tube side input end of the first heat exchanger 2, the tube side output end of the first heat exchanger 2 is connected to the material input end of the concentration kettle 3, the material output end of the concentration kettle 3 is connected to the shell side input end of the first heat exchanger 2, and the shell side output end of the first heat exchanger 2 is connected to the concentrated sulfuric acid treatment device 6;

[0040] The gas output end of the concentration kettle 3 is connected to the condenser 4;

[0041] The vacuum unit 41 is also connected to the steam pipeline 42;

[0042] The vacuum unit 41 and the condenser 4 are both connected to the waste water tank 43 .

[0043] When in use, the dilute sulfuric acid (concentration 60-80wt%) in the factory is concentrated in the dilute sulfuric acid storage tank 1, and then the dilute sulfuric acid in the dilute sulfuric acid storage tank 1 is input into the tube side of the first heat exchanger 2, and the concentrated sulfuric acid with high temperature (concentration of about 96wt%) output by the concentration kettle 3 enters the shell side of the first heat exchanger 2. The two heat through the partition wall heat exchange, while the temperature of the dilute sulfuric acid is increased, the temperature of the concentrated sulfuric acid is reduced, so as to realize the utilization of the waste heat in the concentrated sulfuric acid. The dilute sulfuric acid preheated by the first heat exchanger 2 is input into the concentration kettle 3, and is heated and concentrated. Due to the vacuuming effect of the vacuum unit 41, the boiling point of the concentrated sulfuric acid can be reduced, thereby reducing the heat consumption of heating the concentration kettle 3. The steam supplied by the steam pipeline 42 is used together with the vacuum unit 41, and the vacuum degree of the vacuum unit 41 can be improved by steam injection.

[0044] The dilute sulfuric acid is heated and concentrated in the concentration kettle 3, and the water therein is heated and evaporated and extracted through the vacuum unit 41, and the concentrated sulfuric acid is output from the concentration kettle 3 and enters the shell side of the first heat exchanger 2 to preheat the dilute sulfuric acid. The concentrated sulfuric acid that has been preheated and cooled is output from the shell side outlet of the first heat exchanger 2 and enters the concentrated sulfuric acid treatment device 6 for cooling and storage, thereby realizing the concentration and reuse of the dilute sulfuric acid.

[0045] The steam evaporated during the concentration of dilute sulfuric acid is drawn into the condenser 4 for condensation, and the condensed water formed by the condensation of the steam in the vacuum unit 41 and the condensate in the condenser 4 are collected in the waste water tank 43 for centralized treatment. The uncondensed gas (such as chlorine, hydrogen chloride, etc.) is discharged by the vacuum unit 41 to the tail gas treatment device 5 for harmless treatment.

[0046] The present application provides a dilute sulfuric acid concentration device, which preheats the dilute sulfuric acid by using the waste heat of the concentrated sulfuric acid output from the concentration kettle by setting a first heat exchanger 2, and at the same time, a vacuum unit 41 is set to evacuate the concentration kettle 3 to reduce the concentration temperature, and the steam evaporated by the concentration of the dilute sulfuric acid in the concentration kettle 3 is extracted by the vacuum unit 41, condensed in the condenser 4, and recovered in the wastewater tank 43. The concentrated sulfuric acid after heat exchange and temperature reduction in the first heat exchanger 3 is input into the concentrated sulfuric acid treatment device 6 for recovery. The device of the present application recovers the dilute sulfuric acid after concentration through the coordinated use of the above-mentioned devices, thereby overcoming the disadvantage that the dilute sulfuric acid produced in the chlor-alkali industry is difficult to recycle and reuse, resulting in waste of resources.

[0047] like Figure 2 As shown, optionally, a filtering device 7 is further provided between the dilute sulfuric acid storage tank 1 and the first heat exchanger 2 .

[0048] In the present application, the filtering device 7 is provided to filter out the solid impurities in the dilute sulfuric acid to improve the cleanliness of the dilute sulfuric acid.

[0049] like Figure 3As shown, optionally, a dilute acid washing tower 8 is provided between the first heat exchanger 2 and the concentration kettle 3;

[0050] The tube side output end of the first heat exchanger 2 is connected to the material input end of the dilute acid washing tower 8, and the material output end of the dilute acid washing tower 8 is connected to the material input end of the concentration kettle 3;

[0051] The gas output end of the concentration kettle 3 is connected to the gas input end of the dilute acid washing tower 8 , and the gas output end of the dilute acid washing tower 8 is connected to the condenser 4 .

[0052] In the present application, during use, the dilute sulfuric acid preheated by the first heat exchanger 2 is input from the upper part of the dilute acid washing tower 8, and at the same time, the steam generated by evaporation and concentration in the concentration kettle 3 enters from the lower part of the dilute acid washing tower 8, and counter-currently transfers mass and heat with the dilute sulfuric acid sprayed under the tower top. The steam output by the concentration kettle 3 can perform secondary heating on the dilute sulfuric acid (because the steam has both sensible heat and latent heat), and the steam can also take out the chlorine, hydrogen chloride, etc. in the dilute sulfuric acid, reducing the chlorine content in the dilute sulfuric acid. Moreover, when sulfuric acid is concentrated, it will decompose due to heating to produce a small amount of sulfur trioxide and sulfur dioxide gas, which can be absorbed by the dilute sulfuric acid and converted into sulfuric acid again.

[0053] like Figure 4 As shown, optionally, the concentrated sulfuric acid treatment device 6 includes an intermediate storage tank 61, a second heat exchanger 62 and a concentrated acid storage tank 63 connected in series;

[0054] The intermediate storage tank 61 is connected to the shell side output end of the first heat exchanger 2 .

[0055] When in use, the concentrated sulfuric acid is output from the concentration kettle 3 and enters the shell side of the first heat exchanger 2 to preheat the dilute sulfuric acid. The concentrated sulfuric acid that has been preheated and cooled is output from the shell side outlet of the first heat exchanger 2 and enters the intermediate storage tank 61 for buffering, and then is input into the second heat exchanger 62 for cooling. The cooled concentrated sulfuric acid is input into the concentrated acid storage tank 63 and used for drying gases such as chlorine and hydrogen chloride in the factory, thereby realizing the concentration and reuse of the dilute sulfuric acid.

[0056] like Figure 5 As shown, optionally, the tail gas treatment device 5 includes a tail gas absorption tower 51 and an incinerator 52 connected in series.

[0057] In the present application, when in use, the steam extracted from the concentration kettle 3 (or the dilute acid washing tower 8) enters the condenser 4 for condensation, and the uncondensed gas (such as chlorine, hydrogen chloride, etc.) is discharged by the vacuum unit 41 to the tail gas absorption tower 51 for absorption and treatment, and the tail gas after absorption enters the incinerator 52 for harmless treatment.

[0058] like Figure 6As shown, optionally, a first activated carbon layer 511, a basic alumina layer 512 and a second activated carbon layer 513 are sequentially arranged in the tail gas absorption tower 51 along the gas flow direction.

[0059] In the present application, the first activated carbon layer 511 is filled with granular activated carbon impregnated with alkaline liquid such as sodium hydroxide or potassium hydroxide or carbonated water solution, which can absorb acidic gases in the exhaust gas such as chlorine, hydrogen chloride, etc.; the alkaline alumina layer 512 is filled with granular alkaline alumina, which can further absorb acidic gases and absorb moisture in the exhaust gas at the same time; the second activated carbon layer 513 is filled with granular activated carbon, which is used to further absorb harmful substances in the exhaust gas such as acidic gases.

[0060] like Figure 7 As shown, optionally, the filter device 7 includes a horizontally arranged housing 70, the housing 70 is divided into a first filter chamber and a second filter chamber on one side by a vertically arranged partition 73, and the housing 70 of the first filter chamber and the second filter chamber are respectively closed by a first end cover 701 and a second end cover 702;

[0061] The first filter cavity is provided with multiple layers of coaxially arranged barrel-shaped first filter screens 71, the closed end of the first filter screen 71 is close to the partition plate 73, and the open end is connected to the first end cover 701;

[0062] The first end cover 701 is provided with a first liquid inlet 7101 and a first backwash liquid outlet 7102 ; the side surface of the shell where the first filter cavity is located is provided with a first liquid outlet 7103 and a first backwash liquid inlet 7104 .

[0063] like Figure 7 As shown, optionally, a plurality of coaxially arranged barrel-shaped second filter screens 72 are provided in the second filter cavity, the closed end of the second filter screen 72 is close to the partition plate 73, and the open end is connected to the second end cover 702;

[0064] The second end cover 702 is provided with a second liquid inlet 7201 and a second backwash liquid outlet 7202; the side of the housing where the second filter cavity is located is provided with a second liquid outlet 7203 and a second backwash liquid inlet 7204;

[0065] The first liquid inlet 7101 and the second liquid inlet 7201 are respectively connected to the dilute sulfuric acid storage tank 1 through the first three-way valve 100;

[0066] The first liquid outlet 7103 and the second liquid outlet 7203 are respectively connected to the pipe side inlet of the first heat exchanger 2 through the second three-way valve 200;

[0067] The first backflushing liquid inlet 7104 and the second backflushing liquid inlet 7204 are connected via a control valve 300 .

[0068] When in use, when the filter device 7 filters sulfuric acid, the first three-way valve 100 is first switched to a state where the dilute sulfuric acid storage tank 1 and the first liquid inlet 7101 are connected, while the second liquid inlet 7201 is blocked; the second three-way valve 200 is switched to a state where the first liquid outlet 7103 and the pipe side inlet of the first heat exchanger 2 are connected, while the second liquid outlet 7203 is blocked, and the first backwash liquid outlet 7102 is closed; and the control valve 300 is kept closed. The dilute sulfuric acid containing impurities enters the cylindrical first filter screen 71 from the first liquid inlet 7101 through the first three-way valve 100, and the solid impurities in the dilute sulfuric acid are intercepted and filtered. The filtered dilute sulfuric acid enters the pipe side of the first heat exchanger 2 from the first liquid outlet 7103 through the second three-way valve 200.

[0069] When the first filter screen 71 in the first filter chamber needs to be cleaned after the filter device 7 has been used for a long time, the first three-way valve 100 is switched to a state where the second liquid inlet 7201 is connected and the first liquid inlet 7101 is blocked, and the second three-way valve 200 is switched to a state where the first liquid outlet 7103 and the second liquid outlet 7203 are connected and the first heat exchanger 2 is blocked; the control valve 300 is opened to connect the first backflushing liquid inlet 7104 and the second backflushing liquid inlet 7204; and the second backflushing liquid outlet 7202 is closed. At this time, the dilute sulfuric acid containing impurities enters the second filter chamber, and the dilute sulfuric acid filtered by the second filter 72 passes through the second backwash liquid inlet 7204 and the first backwash liquid inlet 7104, and enters the first filter chamber through the second liquid outlet 7203 and the first liquid outlet 7103, and backwashes the first filter 71. The backwashed sewage is discharged through the first backwash liquid outlet 7102 to the corresponding receiving device for treatment. After the backwash cleaning of the first filter 71 is completed, the control valve 300 is closed, and the second three-way valve 200 is switched to the state of connecting the second liquid outlet 7203 and the first heat exchanger 2 and blocking the first liquid outlet 7103. At this time, the second filter 72 in the second filter chamber can be used to filter the dilute sulfuric acid. The filtering process is the same as the working process of the first filter 71, which will not be repeated here. When the second filter 72 needs to be cleaned, the above-mentioned backwashing method can be used to backwash the second filter 72 using the dilute sulfuric acid filtered by the first filter 71.

[0070] The present application provides a dilute sulfuric acid concentration device, the working process of which is as follows:

[0071] When in use, the dilute sulfuric acid (concentration 60-80wt%) in the factory is concentrated in the dilute sulfuric acid storage tank 1, and then the dilute sulfuric acid in the dilute sulfuric acid storage tank 1 is input into the filter device 7 for filtering. In this application, the filtration of sulfuric acid by the first filter chamber is taken as an example to illustrate that when the filter device 7 filters sulfuric acid, the first three-way valve 100 is first switched to a state of connecting the dilute sulfuric acid storage tank 1 and the first liquid inlet 7101, while blocking the second liquid inlet 7201; the second three-way valve 200 is switched to a state of connecting the first liquid outlet 7103 and the pipe side inlet of the first heat exchanger 2, while blocking the second liquid outlet 7203; and the first backwash liquid outlet 7102 is closed; and the control valve 300 is kept closed. The dilute sulfuric acid containing impurities enters the first cylindrical filter screen 71 from the first liquid inlet 7101 through the first three-way valve 100, and the solid impurities in the dilute sulfuric acid are intercepted and filtered. The filtered dilute sulfuric acid enters the tube side of the first heat exchanger 2 from the first liquid outlet 7103 through the second three-way valve 200, and the high-temperature concentrated sulfuric acid (with a concentration of about 96wt%) output by the concentrator 3 enters the shell side of the first heat exchanger 2. The two exchange heat through the partition wall, and while the temperature of the dilute sulfuric acid increases, the temperature of the concentrated sulfuric acid is reduced, thereby realizing the utilization of the waste heat in the concentrated sulfuric acid. The dilute sulfuric acid preheated by the first heat exchanger 2 is input from the upper part of the dilute acid washing tower 8, and at the same time, the steam generated by evaporation and concentration in the concentration kettle 3 enters from the lower part of the dilute acid washing tower 8, and performs countercurrent mass transfer and heat transfer with the dilute sulfuric acid sprayed under the tower top. The steam output from the concentration kettle 3 can perform secondary heating on the dilute sulfuric acid (because the steam has both sensible heat and latent heat), and the steam can also take out chlorine, hydrogen chloride, etc. in the dilute sulfuric acid, thereby reducing the chlorine content in the dilute sulfuric acid.

[0072] The dilute sulfuric acid further heated by the dilute acid washing tower 8 enters the concentration kettle 3 for heating and concentration. Due to the vacuuming effect of the vacuum unit 41, the boiling point of the concentrated sulfuric acid can be lowered, thereby reducing the heat consumption for heating the concentration kettle 3.

[0073] The concentrated dilute sulfuric acid is heated in the concentration kettle 3, and the water, chlorine, hydrogen chloride, etc. therein are evaporated to form steam, which is pumped into the dilute acid washing tower 8 for mass and heat transfer with the newly added dilute sulfuric acid, and the concentrated sulfuric acid is output from the concentration kettle 3 and enters the shell side of the first heat exchanger 2 to preheat the dilute sulfuric acid. The concentrated sulfuric acid after preheating the dilute sulfuric acid and cooling is output from the shell side outlet of the first heat exchanger 2 to enter the intermediate storage tank 61 for buffering, and then input into the second heat exchanger 62 for cooling. The cooled concentrated sulfuric acid is input into the concentrated acid storage tank 63 for drying gases such as chlorine and hydrogen chloride in the factory, thereby realizing the concentration and reuse of the dilute sulfuric acid.

[0074] Since the steam supplied by the steam pipeline 42 is used together with the vacuum unit 41, the vacuum degree of the vacuum unit 41 can be improved by steam injection. The vacuum unit 41 evacuates the dilute acid washing tower 8 and the concentration kettle 3. The steam evaporated during the concentration of dilute sulfuric acid is drawn into the dilute acid washing tower 8 for mass and heat transfer with the newly added dilute sulfuric acid, and then enters the condenser 4 for condensation. The condensed water formed by the condensation of the steam in the vacuum unit 41 and the condensate in the condenser 4 are collected in the wastewater tank 43 for centralized treatment. The uncondensed gas (such as chlorine, hydrogen chloride, etc.) is discharged by the vacuum unit 41 to the tail gas absorption tower 51, and the acidic gas in the tail gas is absorbed and removed by the first activated carbon layer 511, the basic alumina layer 512 and the second activated carbon layer 513 in sequence. The tail gas after absorption enters the incinerator 52 for harmless treatment.

[0075] When the first filter screen 71 in the first filter chamber needs to be cleaned after the filter device 7 has been used for a long time, the first three-way valve 100 is switched to a state where the second liquid inlet 7201 is connected and the first liquid inlet 7101 is blocked, and the second three-way valve 200 is switched to a state where the first liquid outlet 7103 and the second liquid outlet 7203 are connected and the first heat exchanger 2 is blocked; the control valve 300 is opened to connect the first backflushing liquid inlet 7104 and the second backflushing liquid inlet 7204; and the second backflushing liquid outlet 7202 is closed. At this time, the dilute sulfuric acid containing impurities enters the second filter chamber, and the dilute sulfuric acid filtered by the second filter 72 enters the first filter chamber through the second backwash liquid inlet 7204 and the first backwash liquid inlet 7104, and through the second liquid outlet 7203 and the first liquid outlet 7103, respectively, to backwash the first filter 71, and the backwashed dirty acid is discharged through the first backwash liquid outlet 7102 to the corresponding receiving device for treatment. After the backwash cleaning of the first filter 71 is completed, the control valve 300 is closed, and the second three-way valve 200 is switched to the state of connecting the second liquid outlet 7203 and the first heat exchanger 2 and blocking the first liquid outlet 7103. At this time, the second filter 72 in the second filter chamber can be used to filter the dilute sulfuric acid. The filtering process is the same as the working process of the first filter 71, which will not be repeated here. When the second filter 72 needs to be cleaned, the above-mentioned backwashing method can be used to backwash the second filter 72 using the dilute sulfuric acid filtered by the first filter 71.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features therein may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A dilute sulfuric acid concentration device, characterized in that: It comprises a dilute sulfuric acid storage tank (1), a first heat exchanger (2), a concentration kettle (3), a condenser (4), a vacuum unit (41) and an exhaust gas treatment device (5) which are connected in series in sequence; The dilute sulfuric acid storage tank (1) is connected to the tube side input end of the first heat exchanger (2), the tube side output end of the first heat exchanger (2) is connected to the material input end of the concentration kettle (3), the material output end of the concentration kettle (3) is connected to the shell side input end of the first heat exchanger (2), and the shell side output end of the first heat exchanger (2) is connected to the concentrated sulfuric acid treatment device (6); The gas output end of the concentration kettle (3) is connected to the condenser (4); The vacuum unit (41) is also connected to a steam pipeline (42); The vacuum unit (41) and the condenser (4) are both connected to the waste water tank (43).

2. The dilute sulfuric acid concentration device according to claim 1, characterized in that: A filtering device (7) is also provided between the dilute sulfuric acid storage tank (1) and the first heat exchanger (2).

3. The dilute sulfuric acid concentration device according to claim 1, characterized in that: A dilute acid washing tower (8) is provided between the first heat exchanger (2) and the concentration kettle (3); The tube side output end of the first heat exchanger (2) is connected to the material input end of the dilute acid washing tower (8), and the material output end of the dilute acid washing tower (8) is connected to the material input end of the concentration kettle (3); The gas output end of the concentration kettle (3) is connected to the gas input end of the dilute acid washing tower (8), and the gas output end of the dilute acid washing tower (8) is connected to the condenser (4).

4. The dilute sulfuric acid concentration device according to claim 1, characterized in that: The concentrated sulfuric acid treatment device (6) comprises an intermediate storage tank (61), a second heat exchanger (62) and a concentrated acid storage tank (63) which are connected in series in sequence; The intermediate storage tank (61) is connected to the shell side output end of the first heat exchanger (2).

5. The dilute sulfuric acid concentration device according to any one of claims 1 to 4, characterized in that: The tail gas treatment device (5) comprises a tail gas absorption tower (51) and an incinerator (52) which are connected in series.

6. The dilute sulfuric acid concentration device according to claim 5, characterized in that: A first activated carbon layer (511), a basic alumina layer (512) and a second activated carbon layer (513) are sequentially arranged in the tail gas absorption tower (51) along the gas flow direction.

7. The dilute sulfuric acid concentration device according to claim 2, characterized in that: The filtering device (7) comprises a horizontally arranged housing (70), wherein the housing (70) is divided into a first filter chamber and a second filter chamber on one side by a vertically arranged partition (73), and the housings (70) of the first filter chamber and the second filter chamber are respectively closed by a first end cover (701) and a second end cover (702); The first filter cavity is provided with multiple layers of coaxially arranged barrel-shaped first filter screens (71), the closed end of the first filter screen (71) is close to the partition plate (73), and the open end is connected to the first end cover (701); The first end cover (701) is provided with a first liquid inlet (7101) and a first backflushing liquid outlet (7102); the side of the shell where the first filter cavity is located is provided with a first liquid outlet (7103) and a first backflushing liquid inlet (7104).

8. The dilute sulfuric acid concentration device according to claim 7, characterized in that: The second filter cavity is provided with multiple layers of coaxially arranged barrel-shaped second filter screens (72), the closed end of the second filter screen (72) is close to the partition plate (73), and the open end is connected to the second end cover (702); The second end cover (702) is provided with a second liquid inlet (7201) and a second backwash liquid outlet (7202); the side of the housing where the second filter cavity is located is provided with a second liquid outlet (7203) and a second backwash liquid inlet (7204); The first liquid inlet (7101) and the second liquid inlet (7201) are respectively connected to the dilute sulfuric acid storage tank (1) via a first three-way valve (100); The first liquid outlet (7103) and the second liquid outlet (7203) are respectively connected to the pipe side inlet of the first heat exchanger (2) through the second three-way valve (200); The first backflushing liquid inlet (7104) and the second backflushing liquid inlet (7204) are connected via a control valve (300).

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