Subsystem for reducing and removing hydrogen peroxide in dilute sulphuric acid, tail gas desulfurization system and method

Abstract

The invention belongs to the technical field of sulfuric acid production, and particularly relates to a subsystem for reducing and removing hydrogen peroxide in dilute sulfuric acid and a tail gas desulfurization system and method. The system comprises a hydrogen peroxide-containing dilute sulphuric acid conveying pipeline, one end of the hydrogen peroxide-containing dilute sulphuric acid conveying pipeline is communicated with a hydrogen peroxide-containing dilute sulphuric acid supply side, the other end of the hydrogen peroxide-containing dilute sulphuric acid conveying pipeline is communicated with a reducer, and the hydrogen peroxide-containing dilute sulphuric acid conveying pipeline is provided with a flow regulating valve or a regulating valve group; the reducer is also provided with a gas inlet, a gas outlet and a dilute sulfuric acid outlet; the air inlet is communicated with a first absorption tower air outlet pipe, and the air outlet is communicated with a drying tower air suction pipe. The method is used for solving the technical problems that in the prior art, a method for removing hydrogen peroxide from dilute sulphuric acid containing hydrogen peroxide is high in cost, and waste is still generated.

Description

Technical Field

[0001] The invention belongs to the technical field of sulfuric acid production, and in particular relates to a subsystem for reducing and removing hydrogen peroxide in dilute sulfuric acid, a tail gas desulfurization system and a method. Background Art

[0002] Among the many optional methods for removing sulfur dioxide from flue gas, the hydrogen peroxide desulfurization process first has the advantages of high desulfurization efficiency, simple process flow, reliable system operation, and easy maintenance. It also has a very distinct advantage: the dilute sulfuric acid produced has recycling value, especially for factories that need to use dilute sulfuric acid or acid production systems that need process water replenishment. Its advantages are more prominent. At present, it is more and more widely used in non-ferrous smelting and acid production industries. In particular, after the tail gas of the acid production system is desulfurized with hydrogen peroxide, the dilute sulfuric acid produced can be directly returned to the dry absorption process to adjust the acid concentration, which not only recovers sulfur resources but also has no additional pollutant output. It is one of the more ideal resource-based desulfurization methods.

[0003] Since the desulfurization system is a continuous production device, the circulating dilute sulfuric acid used as the desulfurization liquid must contain hydrogen peroxide.

[0004] Hydrogen peroxide is a strong oxidant and is highly corrosive. A solution composed of hydrogen peroxide and sulfuric acid in a certain ratio is a common printed circuit etching solution, which can corrode copper at 38°C. This shows how corrosive it is. In the hydrogen peroxide desulfurization process, the recommended materials for equipment and pipelines in contact with hydrogen peroxide are corrosion-resistant materials such as polytetrafluoroethylene, fiberglass, high-density polyethylene, polypropylene, 321, 316 L, etc.

[0005] In addition, hydrogen peroxide will decompose when the temperature is above 35°C or when it comes into contact with many common metal ions. This process will release a large amount of heat, which will further intensify the decomposition reaction. The cycle will continue and may even cause an explosion in the end.

[0006] As a result, the subsequent use of dilute sulfuric acid containing residual hydrogen peroxide has many restrictions and troubles, which at least affects the quality of sulfuric acid products and may also cause unpredictable risks to dilute sulfuric acid users: serious corrosion and environmental pollution, explosion risks, etc. Therefore, some methods must be used to remove residual hydrogen peroxide from dilute sulfuric acid. GB51284 also clearly states that the residual hydrogen peroxide in the by-product dilute sulfuric acid should be reduced and decomposed before being discharged from the desulfurization system.

[0007] However, the existing methods for removing hydrogen peroxide either require heating in combination with a catalyst or adding a loaded reducing agent. Regardless of which method is adopted, it requires a large production cost and also generates additional waste. Summary of the invention

[0008] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, and provide a subsystem for reducing and removing hydrogen peroxide in dilute sulfuric acid, a tail gas desulfurization system and a method, so as to solve the technical problems that the method for removing hydrogen peroxide from dilute sulfuric acid containing hydrogen peroxide in the prior art is high in cost and still generates waste. The technical solution of the present invention to solve the above technical problem is as follows: a subsystem for reducing and removing hydrogen peroxide in dilute sulfuric acid comprises: A dilute sulfuric acid delivery pipeline containing hydrogen peroxide, one end of which is connected to the dilute sulfuric acid supply side containing hydrogen peroxide, the other end of which is connected to the reducer, and a flow regulating valve or a regulating valve group is provided on the dilute sulfuric acid delivery pipeline containing hydrogen peroxide; The reducer is also provided with an air inlet and an air outlet, as well as a dilute sulfuric acid discharge port; The air inlet is communicated with an air outlet pipe of an absorption tower, and the air outlet is communicated with an air intake pipe of a drying tower.

[0009] The present invention introduces SO2 from the outlet pipe of an absorption tower of a sulfuric acid plant into a reducer, and uses the reducing property of SO2 to reduce hydrogen peroxide, which can not only remove hydrogen peroxide, but also further generate sulfuric acid, thereby increasing the concentration of dilute sulfuric acid, without generating waste and using a loaded reducing agent, thereby saving production costs.

[0010] Furthermore: the reducer includes a reduction and decomposition section and a storage tank section, the reduction and decomposition section is arranged above the storage tank section and is connected, and the reduction and decomposition section is a gas-liquid mass transfer device.

[0011] The beneficial effects of adopting this step are as follows: the gas-liquid mass transfer equipment is generally a packed tower or an air spray tower, etc. The reducer can not only use the gas-liquid mass transfer equipment as a reduction and decomposition section to improve the gas-liquid mass transfer efficiency and increase the gas-liquid contact area, thereby enhancing the removal effect of residual hydrogen peroxide, but also use the storage tank section as a storage space for dilute sulfuric acid after the removal of hydrogen peroxide.

[0012] The present invention also provides a tail gas desulfurization system, comprising: A tail suction tower, wherein the tail suction tower is provided with a tail suction circulation pipeline, and the tail suction circulation pipeline is provided with a tail suction circulation pump; A subsystem for reducing and removing hydrogen peroxide from dilute sulfuric acid as described in any one of the above, wherein the supply side of the dilute sulfuric acid containing hydrogen peroxide is the outlet pipe of the tail suction circulation pump; A hydrogen peroxide delivery pipeline, one end of which is connected to the hydrogen peroxide storage tank, and the other end of which is connected to the inlet pipe of the tail suction circulation pump, wherein a hydrogen peroxide metering pump and a flow regulating actuator are sequentially arranged in the hydrogen peroxide delivery pipeline; A water supply pipeline is also provided outside the tail suction tower. The water supply pipeline is divided into two routes, one route is connected with the bottom of the tail suction tower, and the other route is used to flush the tail suction electric demister on the top of the tail suction tower.

[0013] In the present invention, the hydrogen peroxide delivery pipeline provides the desulfurization reaction raw materials to the tail absorption tower. In order to desulfurize the tail gas, the hydrogen peroxide will inevitably be excessive, and dilute sulfuric acid containing hydrogen peroxide will be produced. At this time, the dilute sulfuric acid containing hydrogen peroxide enters the reducer from the hydrogen peroxide-containing dilute sulfuric acid delivery pipeline to remove the residual hydrogen peroxide, and pure dilute sulfuric acid can be obtained.

[0014] Further: at least two hydrogen peroxide metering pumps are provided in the hydrogen peroxide delivery pipeline, and the two hydrogen peroxide metering pumps are connected in parallel in the hydrogen peroxide delivery pipeline; At least two tail suction circulation pumps are arranged in the tail suction circulation pipeline, and the two tail suction circulation pumps are connected in parallel in the tail suction circulation pipeline.

[0015] The beneficial effect of adopting this step is that at least two hydrogen peroxide metering pumps and tail suction circulation pumps can be used as one in use and one in reserve to ensure that the system can operate uninterruptedly.

[0016] For the above tail gas desulfurization system, the present invention also provides a method of the tail gas desulfurization system, comprising the following steps: S1. During the initial operation, process water and 27.5% hydrogen peroxide solution are injected into the tailing tower respectively. When the liquid level reaches the specified height, the tailing circulation pump is started to start circulating spraying. At this time, the dilute sulfuric acid delivery pipeline containing hydrogen peroxide is not opened; S2. As SO2 in the acid-making tail gas is continuously removed, the concentration of dilute sulfuric acid at the bottom of the tail absorption tower is continuously increased. The concentration of dilute sulfuric acid and the content of hydrogen peroxide therein are controlled through the hydrogen peroxide delivery pipeline and the water supply pipeline to achieve standard emission of waste gas; the excess dilute sulfuric acid containing residual hydrogen peroxide generated in this process is delivered to the upper part of the reduction decomposition section of the reducer through the dilute sulfuric acid delivery pipeline containing hydrogen peroxide; S3, the process gas containing 0.2%-0.7% SO2 by volume in the outlet pipe of an absorption tower is excessively injected into the bottom of the reduction decomposition section of the reducer, and countercurrently contacts with the excess dilute sulfuric acid containing residual hydrogen peroxide from the upper part of the reduction decomposition section of the reducer; S4, the excess SO2 in the reducer, and a small amount of unabsorbed SO3 are sucked into the drying tower suction pipe; S5. The dilute sulfuric acid from which the residual hydrogen peroxide is removed in the reducer is transported to the acid circulation tank of the drying tower, or is transported to other dilute sulfuric acid users.

[0017] The present invention utilizes the abundant SO2 in the sulfuric acid plant as a reducing agent to reduce hydrogen peroxide to generate dilute sulfuric acid, which can remove the hydrogen peroxide in the dilute sulfuric acid and increase the concentration of the dilute sulfuric acid. The excess SO2 and a small amount of unabsorbed SO3 are returned to the acid-making flue gas, without discharging any waste and without causing any impact on the environment. The entire acid-making system realizes a complete closed loop.

[0018] The beneficial effects of the present invention are: The present invention does not need to use externally purchased loading reducing agents or other reducing agents. It only needs to use the flue gas containing SO2 generated in the acid production process to reduce hydrogen peroxide, so as to achieve the purpose of removing hydrogen peroxide from dilute sulfuric acid. It not only ensures the quality of the discharged dilute sulfuric acid, but also saves costs and does not generate new waste, which meets the requirements of green production of current chemical enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 This is a schematic diagram of the structure of a subsystem for reducing and removing hydrogen peroxide in dilute sulfuric acid provided by the present invention; Figure 2 A schematic diagram of the structure of a reducer in a subsystem for reducing and removing hydrogen peroxide in dilute sulfuric acid provided by the present invention; Figure 3 This is a schematic structural diagram of the tail gas desulfurization system provided by the present invention.

[0021] Reference numerals: 1- tail absorption tower; 2- hydrogen peroxide delivery pipeline; 3- tail absorption circulation pipeline; 4- reducer; 5- tail smoke chimney; 6- dry absorption section tail gas; 7- first absorption tower outlet pipe; 8- drying tower suction pipe; 9- drying tower acid circulation tank or dilute sulfuric acid user; 10- water supply pipeline; 11-tail suction electric demister; 12-drain outlet; 21-hydrogen peroxide storage tank; 22-hydrogen peroxide metering pump; 23-flow regulating actuator; 31-tail suction circulation pump; 32-dilute sulfuric acid delivery pipeline containing hydrogen peroxide; 33-flow regulating valve; 41-reduction decomposition section; 42-storage tank section; 51-SO2 sensor. DETAILED DESCRIPTION

[0022] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention. It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0023] Example First, the basis of the present application is the chemical reaction formula (1) or (2) (3) (4).

[0024] SO2+H2O2→ H2SO4 (1) or SO2 + H2O → H2SO3 (2) 2H2SO3+ H2O2→ 2H2O + H2S2O6 (3) H2S2O6 + H2O2 → 2H2SO4 (4) like Figure 1 As shown, the subsystem for reducing and removing hydrogen peroxide in dilute sulfuric acid provided by the present invention comprises: A dilute sulfuric acid delivery pipeline 32 containing hydrogen peroxide, one end of which is connected to the supply side of the dilute sulfuric acid containing hydrogen peroxide, and the other end of which is connected to the reducer 4. A flow regulating valve 33 or a regulating valve group is provided on the dilute sulfuric acid delivery pipeline 32 containing hydrogen peroxide, and the flow regulating valve 33 or the regulating valve group is used to adjust the delivery amount of the dilute sulfuric acid containing hydrogen peroxide.

[0025] The reducer 4 is also provided with an air inlet and an air outlet, as well as a dilute sulfuric acid outlet; the dilute sulfuric acid outlet delivers the dilute sulfuric acid to the drying tower acid circulation tank 9 or the dilute sulfuric acid user; The air inlet is communicated with an air outlet pipe 7 of an absorption tower, and the air outlet is communicated with an air intake pipe 8 of a drying tower.

[0026] The present invention introduces SO2 from the outlet pipe 7 of an absorption tower of a sulfuric acid plant into a reducer 4, and uses the reducing property of SO2 to reduce hydrogen peroxide, which can not only remove hydrogen peroxide, but also further produce sulfuric acid, increase the concentration of dilute sulfuric acid, and does not generate waste, nor use a loaded reducing agent, thereby saving production costs.

[0027] On the basis of the above technical solution, the reducer 4 includes a reduction and decomposition section 41 and a storage tank section 42. The reduction and decomposition section 41 is arranged above the storage tank section 42 and is connected. The reduction and decomposition section 41 is a gas-liquid mass transfer device.

[0028] The gas-liquid mass transfer equipment is generally a packed tower or an air spray tower, etc. The reducer 4 can not only use the gas-liquid mass transfer equipment as the reduction and decomposition section 41 to improve the gas-liquid mass transfer efficiency and increase the gas-liquid contact area, thereby enhancing the removal effect of residual hydrogen peroxide, but also use the storage tank section 42 as a storage space for dilute sulfuric acid after removing hydrogen peroxide.

[0029] The present invention also provides a tail gas desulfurization system, comprising: A tail suction tower 1, which is also a gas-liquid mass transfer device, can be one of the types of a packed tower, an air spray tower, a power wave washing tower, etc. The tail suction tower 1 is provided with a tail suction circulation pipeline 3, and the tail suction circulation pipeline 3 is provided with a tail suction circulation pump 31; the inlet pipe of the tail suction circulation pump 31 is connected to the bottom of the tail suction tower 1; the outlet pipe of the tail suction circulation pump 31 is connected to the tail suction tower high-efficiency reverse spray power wave scrubber (the tail suction tower of this embodiment preferably uses a power wave washing tower type); In the subsystem for reducing and removing hydrogen peroxide from dilute sulfuric acid as described in any one of the above, the dilute sulfuric acid containing hydrogen peroxide supply side is the outlet pipe of the tail suction circulation pump 31; that is, one end of the dilute sulfuric acid delivery pipeline 32 containing hydrogen peroxide is connected to the outlet pipe of the tail suction circulation pump 31, and the other end is connected to the reducer 4; A hydrogen peroxide delivery pipeline 2, one end of which is connected to a hydrogen peroxide storage tank 21, and the other end of which is connected to an inlet pipe of the tail suction circulation pump 31. A hydrogen peroxide metering pump 22 and a flow regulating actuator 23 are sequentially arranged in the hydrogen peroxide delivery pipeline 2; the flow regulating actuator 23 is program-interlocked with a SO2 sensor 51 at the top of the tail suction chimney 5; A water supply pipeline 10 is also provided outside the tail absorption tower 1. The water supply pipeline 10 is divided into two paths, one of which is connected to the bottom of the tail absorption tower 1, and the other is used to flush the tail absorption electric demister 11 on the top of the tail absorption tower 1. On the one hand, since the acid-making tail gas is a dry gas without water, it will inevitably humidify and take away moisture during the desulfurization process, so the tail absorption tower 1 must be replenished with water through the water supply pipeline 10; on the other hand, a high concentration of dilute sulfuric acid will be unfavorable for the desulfurization reaction, so water must be added to adjust the concentration of dilute sulfuric acid; in addition, the tail absorption electric demister 11 can also be cleaned.

[0030] In the present invention, the hydrogen peroxide delivery pipeline provides the desulfurization reaction raw materials to the tail absorption tower. In order to desulfurize the tail gas, the hydrogen peroxide will inevitably be excessive, and dilute sulfuric acid containing hydrogen peroxide will be produced. At this time, the dilute sulfuric acid containing hydrogen peroxide enters the reducer from the hydrogen peroxide-containing dilute sulfuric acid delivery pipeline to remove the residual hydrogen peroxide, and pure dilute sulfuric acid can be obtained.

[0031] On the basis of the above technical solution, at least two hydrogen peroxide metering pumps 22 are provided in the hydrogen peroxide delivery pipeline 2, and the two hydrogen peroxide metering pumps 22 are connected in parallel in the hydrogen peroxide delivery pipeline 2; At least two tail suction circulation pumps 31 are disposed in the tail suction circulation pipeline 3 , and the two tail suction circulation pumps 31 are connected in parallel in the tail suction circulation pipeline 3 .

[0032] At least two hydrogen peroxide metering pumps 22 and tail suction circulation pumps 31 can be used in one and standby in the other to ensure that the system can run uninterruptedly.

[0033] The present invention also provides a method for a tail gas desulfurization system, comprising the following steps: S1. During the initial operation, process water and 27.5% hydrogen peroxide solution are respectively injected into the tail absorption tower 1. After the liquid level reaches the specified height, the tail absorption circulation pump 31 is started to start circulating spraying. At this time, the dilute sulfuric acid delivery pipeline 32 containing hydrogen peroxide is not opened; after a period of operation, the tail gas desulfurization system will reach a normal state or steady state, at which time the mass fraction of sulfuric acid in the circulating dilute sulfuric acid is 20%-30%; the mass fraction of residual hydrogen peroxide in the circulating dilute sulfuric acid is 0.01%-0.8%; S2. As SO2 in the acid-making tail gas is continuously removed, the concentration of the dilute sulfuric acid at the bottom of the tail absorption tower 1 is continuously increased. By adjusting the flow rates of the hydrogen peroxide delivery pipeline 2 and the water supply pipeline 10, the concentration of the dilute sulfuric acid and the hydrogen peroxide content therein are controlled to achieve standard emission of waste gas; the excess dilute sulfuric acid containing residual hydrogen peroxide generated in this process is delivered to the upper part of the reduction decomposition section 41 of the reducer 4 through the dilute sulfuric acid delivery pipeline 32 containing hydrogen peroxide; S3, the process gas containing 0.2%-0.7% SO2 by volume in the outlet pipe 7 of an absorption tower is excessively injected into the bottom of the reduction decomposition section 41 of the reducer 4, and countercurrently contacts with the excess dilute sulfuric acid containing residual hydrogen peroxide from the upper part of the reduction decomposition section 41 of the reducer 4; since the proportion of residual hydrogen peroxide in the dilute sulfuric acid mentioned in S1 is relatively small, contact with excess process gas can ensure the removal of residual hydrogen peroxide in the dilute sulfuric acid, and this process is feasible; The excess SO2 in S4 and the reducer 4, as well as a small amount of unabsorbed SO3, are sucked into the drying tower suction pipe 8; S5. The dilute sulfuric acid from which the residual hydrogen peroxide is removed in the reducer 4 is transported to the drying tower acid circulation tank 9, or is transported to other dilute sulfuric acid users.

[0034] In the above S3~S5, the process gas containing 0.2%-0.7% SO2 by volume is in the outlet pipe 7 of an absorption tower. It is located behind the sulfur dioxide blower and has a relatively high gas pressure. It can be injected into the bottom of the reduction decomposition section of the reducer 4 without additional power, and countercurrently contacts with the excess dilute sulfuric acid containing residual hydrogen peroxide from the upper part of the reduction decomposition section of the reducer 4; SO2 has a stronger reducing property. After contacting with the strong oxidant hydrogen peroxide, the two undergo a redox reaction to obtain dilute sulfuric acid without hydrogen peroxide; to ensure the removal effect, an excess amount of SO2 gas relative to the redox reaction is usually introduced, and the excess SO2 and a small amount of unabsorbed SO3 are sucked into the drying tower intake pipe 8 by the sulfur dioxide blower; the dilute sulfuric acid that completes the decomposition and reduction of the residual hydrogen peroxide in the reducer 4 is generally sent to the dry absorption process drying tower acid circulation tank or the dilute sulfuric acid user 9; The SO2 sensor 51 of the tail smoke chimney 5 at the top of the tail absorption tower 1 detects the SO2 content in the exhaust gas to be discharged. When the detection result is higher than the preset value of the interlock control program, the flow regulating actuator 23 of the hydrogen peroxide delivery pipeline 2 increases the opening, and the amount of hydrogen peroxide added to the tail absorption tower 1 is increased; conversely, the flow regulating actuator 23 of the hydrogen peroxide delivery pipeline 2 decreases the opening, and the amount of hydrogen peroxide added to the tail absorption tower 1 is reduced; In order to achieve ultra-low exhaust emission indicators, a first-stage tail suction electric demister 11 can be added after the tail suction tower 1.

[0035] The acid-making tail gas after desulfurization can meet the ultra-low emission standards required by current environmental protection requirements; The excess dilute sulfuric acid produced by the desulfurization of acid-making tail gas can meet a variety of usage scenarios after the residual hydrogen peroxide is removed: such as process water replenishment in the dry absorption process of sulfuric acid plants, acid for tower washing in ammonia desulfurization, acid for coal gas deammoniation in coking plants, etc.

[0036] By comparing with the existing technology for removing hydrogen peroxide from dilute sulfuric acid, the following advantages are summarized: 1. In the process of sulfuric acid production, relatively clean SO2 must always be produced first. Therefore, using SO2 as a reducing agent is both feasible and convenient. 2. In sulfuric acid plants, the source of SO2 is stable and sufficient. As long as there is acid production tail gas to be treated, there will be sufficient SO2 supply; 3. SO2 is used to reduce the residual hydrogen peroxide in dilute sulfuric acid. The product is still mainly dilute sulfuric acid. After the entire reduction process is completed, the biggest impact is just a slight increase in the concentration of the discharged dilute sulfuric acid. It usually has only benefits and no harm to the subsequent utilization of dilute sulfuric acid; 4. The unreacted excess SO2 and a small amount of unabsorbed SO3 are returned to the acid-making flue gas, without any waste being discharged and without any impact on the environment; the entire acid-making system realizes a complete closed loop; 5. No need to purchase external loading reducing agent or other reducing agent, saving the operating cost of sulfuric acid plant; 6. No loading or other reducing agents are used, which can improve the continuity and stability of sulfuric acid plant operation; 7. No loading reducing agent is used, no new waste is generated, and it meets the requirements of green production in chemical plants.

[0037] Finally, the system also requires matching flow meters, temperature gauges, pressure gauges, liquid level meters and other instrument devices, which belong to the existing technology and will not be described in detail.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with 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 invention.

Claims

1. A subsystem for reducing and removing hydrogen peroxide from dilute sulfuric acid, characterized in that: include: A dilute sulfuric acid delivery pipeline containing hydrogen peroxide, one end of which is connected to the dilute sulfuric acid supply side containing hydrogen peroxide, the other end of which is connected to the reducer, and a flow regulating valve or a regulating valve group is provided on the dilute sulfuric acid delivery pipeline containing hydrogen peroxide; The reducer is also provided with an air inlet and an air outlet, as well as a dilute sulfuric acid discharge port; The air inlet is communicated with an air outlet pipe of an absorption tower, and the air outlet is communicated with an air intake pipe of a drying tower.

2. The subsystem for reducing and removing hydrogen peroxide in dilute sulfuric acid according to claim 1, characterized in that: The reducer comprises a reduction and decomposition section and a storage tank section. The reduction and decomposition section is arranged above and connected to the storage tank section. The reduction and decomposition section is a gas-liquid mass transfer device.

3. Tail gas desulfurization system, characterized in that: include: A tail suction tower, wherein the tail suction tower is provided with a tail suction circulation pipeline, and the tail suction circulation pipeline is provided with a tail suction circulation pump; The subsystem for reducing and removing hydrogen peroxide from dilute sulfuric acid as described in claim 1 or 2, wherein the supply side of the dilute sulfuric acid containing hydrogen peroxide is the outlet pipe of the tail suction circulation pump; A hydrogen peroxide delivery pipeline, one end of which is connected to the hydrogen peroxide storage tank, and the other end of which is connected to the inlet pipe of the tail suction circulation pump, wherein a hydrogen peroxide metering pump and a flow regulating actuator are sequentially arranged in the hydrogen peroxide delivery pipeline; A water supply pipeline is also provided outside the tail suction tower. The water supply pipeline is divided into two routes, one route is connected with the bottom of the tail suction tower, and the other route is used to flush the tail suction electric demister on the top of the tail suction tower.

4. The tail gas desulfurization system according to claim 3, characterized in that: At least two hydrogen peroxide metering pumps are arranged in the hydrogen peroxide delivery pipeline, and the two hydrogen peroxide metering pumps are connected in parallel in the hydrogen peroxide delivery pipeline; At least two tail suction circulation pumps are arranged in the tail suction circulation pipeline, and the two tail suction circulation pumps are connected in parallel in the tail suction circulation pipeline.

5. A method for a tail gas desulfurization system, characterized in that: The following steps are involved: S1. During the initial operation, process water and 27.5% hydrogen peroxide solution are injected into the tailing tower respectively. When the liquid level reaches the specified height, the tailing circulation pump is started to start circulating spraying. At this time, the dilute sulfuric acid delivery pipeline containing hydrogen peroxide is not opened; S2. As SO2 in the acid-making tail gas is continuously removed, the concentration of dilute sulfuric acid at the bottom of the tail absorption tower is continuously increased. The concentration of dilute sulfuric acid and the content of hydrogen peroxide therein are controlled through the hydrogen peroxide delivery pipeline and the water supply pipeline to achieve standard emission of waste gas; the excess dilute sulfuric acid containing residual hydrogen peroxide generated in this process is delivered to the upper part of the reduction decomposition section of the reducer through the dilute sulfuric acid delivery pipeline containing hydrogen peroxide; S3, the process gas containing 0.2%-0.7% SO2 by volume in the outlet pipe of an absorption tower is excessively injected into the bottom of the reduction decomposition section of the reducer, and countercurrently contacts with the excess dilute sulfuric acid containing residual hydrogen peroxide from the upper part of the reduction decomposition section of the reducer; S4, the excess SO2 in the reducer, and a small amount of unabsorbed SO3 are sucked into the drying tower suction pipe; S5. The dilute sulfuric acid from which the residual hydrogen peroxide is removed in the reducer is transported to the acid circulation tank of the drying tower, or is transported to other dilute sulfuric acid users.

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