Process for the treatment of sulfuric acid emissions in the production of sulfamic acid

Abstract

The application discloses a sulfuric acid discharging treatment process for aminosulfonic acid production and particularly relates to the technical field of aminosulfonic acid production. After sulfonation, the application is characterized in that seven reaction kettles are used for continuous dilution, 22% mother liquor is added into the first kettle, the temperature is controlled, the mother liquor is supplemented in the second dilution kettle, and the specific gravity of the acid is controlled within ±1.70. Since the treatment process continuously dilutes aminosulfonic acid sulfonate, the problems of the prior art, such as high labor intensity, high cost, difficulty in transfer, difficult process control and inconvenient operation, are solved. The continuous dilution process provided by the application is convenient in operation, low in labor intensity, high in product yield and good in product quality. Meanwhile, 60% concentrated sulfuric acid can be maximally recovered and used as a byproduct, the absorption efficiency is high, the SO2 absorption rate reaches 94%, most of the dilute sulfuric acid can be used, and the discharge amount of waste sulfuric acid is reduced.

Description

Technical Field

[0001] This invention relates to the field of aminosulfonic acid production technology, and more specifically, to a sulfuric acid discharge treatment process for aminosulfonic acid production. Background Technology

[0002] The main raw material used in the synthesis of aminosulfonic acid is fuming sulfuric acid. When fuming sulfuric acid participates in the reaction, some sulfur trioxide gas will escape. The tail gas in the aminosulfonic acid production system contains sulfur trioxide gas, acid mist, acidic solid particles and other solid particulate matter. Sulfur trioxide gas and acid mist are highly corrosive to equipment, so the tail gas needs to be recovered and treated to meet emission standards.

[0003] Currently, the main production process for aminosulfonic acid by domestic manufacturers is the sulfonation of urea via fuming acid. Because this process has the advantages of large production capacity, good product quality, safety, and low waste, people are constantly researching this process in order to further improve and perfect it.

[0004] As environmental protection departments have become increasingly stringent in their requirements for wastewater discharge, in addition to requirements on pH value and turbidity, standards for chemical oxygen demand (COD) of industrial wastewater have been introduced. The wastewater generated by the sulfuric acid production system using pyrite in smelting flue gas is rich in organic matter due to incomplete combustion of mineral processing reagents in multi-hearth furnaces, resulting in COD levels in the discharged wastewater approaching or even exceeding environmental protection requirements.

[0005] However, current technology lacks the ability to recover and utilize sulfur trioxide gas in exhaust gases, wasting sulfur trioxide resources and failing to achieve good results in exhaust gas treatment, thus failing to meet environmental protection requirements. Furthermore, it is difficult to achieve low-cost, high-return results in exhaust gas treatment, resulting in certain limitations in current treatment methods. Summary of the Invention

[0006] In order to overcome the above-mentioned defects of the prior art, the present invention provides a sulfuric acid emission treatment process for aminosulfonic acid production. The technical problem to be solved by the present invention is that the current technology lacks the recovery and utilization of sulfur trioxide gas in the exhaust gas, which wastes sulfur trioxide resources and has poor treatment effect on the exhaust gas, failing to meet environmental protection requirements. At the same time, it is difficult to achieve low cost and high benefit in exhaust gas treatment, resulting in certain limitations of the current treatment methods.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a sulfuric acid emission treatment process for aminosulfonic acid production, comprising the following treatment processes:

[0008] Absorption Treatment: The tail gas absorption tower adopts an integrated tower-tank structure. Sulfuric acid tail gas is introduced into the lower absorption section of the absorption tower through a flue gas pipeline. The tail gas flows from bottom to top in the absorption tower and comes into counter-current contact with the absorbent sprayed from top to bottom. The SO2 in the tail gas reacts with the absorbent ammonia in the absorbent to produce ammonium bisulfite and ammonium sulfite. At the same time, ammonium bisulfite and ammonia continue to react to produce ammonium sulfite. When the absorbent reaches a certain concentration, it is sent to the oxidation tower for oxidation and removal of SO2. The sulfuric acid tail gas then enters the upper demisting purification section of the absorption tower.

[0009] The main reactions in the absorption system:

[0010] NH3 + H2O + SO2 → NH4HSO3

[0011] 2NH3 + H2O + SO2 → (NH4)2SO3

[0012] NH4HSO3 + NH3 → (NH4)2SO3

[0013] (NH4)2SO3 + SO2 + H2O → 2NH4HSO3

[0014] SO3 + H2O → H2SO4

[0015] The demisting and purification section is equipped with ammonia removal, water mist removal, and aerosol removal devices. After SO2 is removed, the exhaust gas containing trace amounts of ammonia and water mist flows from bottom to top in the purification section. Through the collision between the exhaust gas and the demisting device and the action of the droplets' own gravity, the exhaust gas is captured and removed and purified. The purified exhaust gas is then introduced into the chimney for emission.

[0016] The process parameters are controlled as follows: pH value between 5.0 and 6.0; liquid-to-gas ratio between 0.5 and 0.8 L / m³. 3 Circulating fluid density 1080-1160 kg / m³ 3 Within the appropriate range, the desulfurization efficiency can reach over 94%. The factors that have the greatest impact on the desulfurization efficiency are the ammonia atomization effect and the pH value. During the design phase, a spiral nozzle is used to increase the contact area between the ammonia water and the flue gas. During production, the pH value is adjusted within the process parameters to control the SO2 content in the gas exiting the tower, ensuring that ρ(SO2) < 100 mg / m³ in the gas discharged from the chimney. 3 Acid mist (p) less than 30 mg / m³ 3 .

[0017] Demineralized water is used to replenish the absorbent to prevent scale formation and calcium salt blockage of the nozzles inside the tower at temperatures above 45°C.

[0018] Oxidation treatment: After absorbing sulfur dioxide and sulfuric acid mist, the absorbent liquid, reaching a certain concentration, is sent to the oxidation tower through fiberglass pipes. At the same time, ammonia water is added to the oxidation tower to adjust the pH value of the solution to 4.5-5.5, so that the ammonium bisulfite in it is neutralized into ammonium sulfite. Compressed air at 100 m3 / h and 100 kPa and low-pressure saturated steam compressed air at 165℃, 0.55 MPa and 34 kg / h are introduced from the bottom of the tower. The compressed air comes into full contact with the heated absorbent liquid through the microporous aeration device at the bottom of the tower, so that the ammonium bisulfite and ammonium sulfite are oxidized into ammonium bisulfate and ammonium sulfate. The oxidation tower adopts perforated aeration oxidation technology.

[0019] The main reactions in the oxidation system are:

[0020] NH4HSO3 + NH3 → (NH4)2SO3

[0021] 2NH4HSO3 + O2 → 2NH4HSO4

[0022] 2(NH4)2SO3 + O2 → 2(NH4)2SO4

[0023] After oxidation, the qualified ammonium sulfate solution overflows from the top of the oxidation tower into the ammonium sulfate tank. Excess compressed air in the oxidation tower is sent to the absorption tower through the gas-liquid balance pipe and is finally discharged with the purified tail gas.

[0024] Sulfuric acid specific gravity control: After sulfonation, continuous dilution is carried out using seven reaction vessels. 22% mother liquor is added to the first vessel and the temperature is controlled. The mother liquor is added to the second dilution vessel, and the specific gravity of the acid is controlled within ±1.70.

[0025] As a further aspect of the present invention: in the absorption treatment, the mass concentration of trace ammonia and large-particle water mist in the exhaust gas is ≤75mg / m³. 3 .

[0026] As a further aspect of the present invention: in the control of the specific gravity of sulfuric acid, the temperature is controlled within 70°C.

[0027] Furthermore, this processing technology has the following main characteristics:

[0028] 1) Use demineralized water to replenish the absorbent to avoid calcium salts clogging the nozzle.

[0029] 2) High absorption efficiency: SO2 absorption rate reaches over 94%, sulfuric acid mist absorption rate reaches over 71%. Before desulfurization, p(SO2) is 720 mg / m3 and sulfuric acid mist (p) is 23 mg / m3. After desulfurization, p(SO2) is 38.5 mg / m3 and sulfuric acid mist (p) is 6.6 mg / m3.

[0030] 3) The oxidation system has a good oxidation effect, and the final product ammonium sulfate solution has a mass fraction of over 99%. The composition of materials before and after oxidation is shown in the table below.

[0031]

[0032] The beneficial effects of this invention are as follows:

[0033] This invention treats the tail gas using seven reaction vessels. Furthermore, because this process continuously dilutes the aminosulfonic acid sulfonate, it completely solves the problems of labor-intensive material transfer in existing technologies. Previously, intermittent dilution was labor-intensive, costly, difficult to transfer, and difficult to control, resulting in inconvenient operation. Therefore, the continuous dilution process provided by this invention is easy to operate, reduces worker labor intensity, and achieves high product yield and quality. Simultaneously, it can recover up to 60% concentration of sulfuric acid as a byproduct, allowing most of the dilute sulfuric acid to be reused, thus reducing the amount of waste sulfuric acid discharged. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1:

[0036] A process for treating sulfuric acid emissions from aminosulfonic acid production includes the following treatment steps:

[0037] Absorption Treatment: The tail gas absorption tower adopts an integrated tower-tank structure. Sulfuric acid tail gas is introduced into the lower absorption section of the absorption tower through a flue gas pipeline. The tail gas flows from bottom to top in the absorption tower and comes into counter-current contact with the absorbent sprayed from top to bottom. The SO2 in the tail gas reacts with the absorbent ammonia in the absorbent to produce ammonium bisulfite and ammonium sulfite. At the same time, ammonium bisulfite and ammonia continue to react to produce ammonium sulfite. When the absorbent reaches a certain concentration, it is sent to the oxidation tower for oxidation and removal of SO2. The sulfuric acid tail gas then enters the upper demisting purification section of the absorption tower.

[0038] The main reactions in the absorption system:

[0039] NH3 + H2O + SO2 → NH4HSO3

[0040] 2NH3 + H2O + SO2 → (NH4)2SO3

[0041] NH4HSO3 + NH3 → (NH4)2SO3

[0042] (NH4)2SO3 + SO2 + H2O → 2NH4HSO3

[0043] SO3 + H2O → H2SO4

[0044] The demisting and purification section is equipped with ammonia removal, water mist removal, and aerosol removal devices. After SO2 is removed, the exhaust gas containing trace amounts of ammonia and water mist flows from bottom to top in the purification section. Through the collision between the exhaust gas and the demisting device and the action of the droplets' own gravity, the exhaust gas is captured and removed and purified. The purified exhaust gas is then introduced into the chimney for emission.

[0045] The process parameters are controlled as follows: pH value between 5.0 and 6.0; liquid-to-gas ratio between 0.5 and 0.8 L / m³. 3 Circulating fluid density 1080-1160 kg / m³ 3 Within the appropriate range, the desulfurization efficiency can reach over 94%. The factors that have the greatest impact on the desulfurization efficiency are the ammonia atomization effect and the pH value. During the design phase, a spiral nozzle is used to increase the contact area between the ammonia water and the flue gas. During production, the pH value is adjusted within the process parameters to control the SO2 content in the gas exiting the tower, ensuring that ρ(SO2) < 100 mg / m³ in the gas discharged from the chimney. 3 Acid mist (p) less than 30 mg / m³ 3 .

[0046] Demineralized water is used to replenish the absorbent to prevent scale formation and calcium salt blockage of the nozzles inside the tower at temperatures above 45°C.

[0047] Oxidation treatment: After absorbing sulfur dioxide and sulfuric acid mist, the absorbent liquid, reaching a certain concentration, is sent to the oxidation tower through fiberglass pipes. At the same time, ammonia water is added to the oxidation tower to adjust the pH value of the solution to 4.5-5.5, so that the ammonium bisulfite in it is neutralized into ammonium sulfite. Compressed air at 100 m3 / h and 100 kPa and low-pressure saturated steam compressed air at 165℃, 0.55 MPa and 34 kg / h are introduced from the bottom of the tower. The compressed air comes into full contact with the heated absorbent liquid through the microporous aeration device at the bottom of the tower, so that the ammonium bisulfite and ammonium sulfite are oxidized into ammonium bisulfate and ammonium sulfate. The oxidation tower adopts perforated aeration oxidation technology.

[0048] The main reactions in the oxidation system are:

[0049] NH4HSO3 + NH3 → (NH4)2SO3

[0050] 2NH4HSO3 + O2 → 2NH4HSO4

[0051] 2(NH4)2SO3 + O2 → 2(NH4)2SO4

[0052] After oxidation, the qualified ammonium sulfate solution overflows from the top of the oxidation tower into the ammonium sulfate tank. Excess compressed air in the oxidation tower is sent to the absorption tower through the gas-liquid balance pipe and is finally discharged with the purified tail gas.

[0053] Example 2:

[0054] A process for treating sulfuric acid emissions from aminosulfonic acid production includes the following treatment steps:

[0055] Absorption Treatment: The tail gas absorption tower adopts an integrated tower-tank structure. Sulfuric acid tail gas is introduced into the lower absorption section of the absorption tower through a flue gas pipeline. The tail gas flows from bottom to top in the absorption tower and comes into counter-current contact with the absorbent sprayed from top to bottom. The SO2 in the tail gas reacts with the absorbent ammonia in the absorbent to produce ammonium bisulfite and ammonium sulfite. At the same time, ammonium bisulfite and ammonia continue to react to produce ammonium sulfite. When the absorbent reaches a certain concentration, it is sent to the oxidation tower for oxidation and removal of SO2. The sulfuric acid tail gas then enters the upper demisting purification section of the absorption tower.

[0056] The main reactions in the absorption system:

[0057] NH3 + H2O + SO2 → NH4HSO3

[0058] 2NH3 + H2O + SO2 → (NH4)2SO3

[0059] NH4HSO3 + NH3 → (NH4)2SO3

[0060] (NH4)2SO3 + SO2 + H2O → 2NH4HSO3

[0061] SO3 + H2O → H2SO4

[0062] The demisting and purification section is equipped with ammonia removal, water mist removal, and aerosol removal devices. After SO2 is removed, the exhaust gas containing trace amounts of ammonia and water mist flows from bottom to top in the purification section. Through the collision between the exhaust gas and the demisting device and the action of the droplets' own gravity, the exhaust gas is captured and removed and purified. The purified exhaust gas is then introduced into the chimney for emission.

[0063] The process parameters are controlled as follows: pH value between 5.0 and 6.0; liquid-to-gas ratio between 0.5 and 0.8 L / m³. 3 Circulating fluid density 1080-1160 kg / m³ 3 Within the appropriate range, the desulfurization efficiency can reach over 94%. The factors that have the greatest impact on the desulfurization efficiency are the ammonia atomization effect and the pH value. During the design phase, a spiral nozzle is used to increase the contact area between the ammonia water and the flue gas. During production, the pH value is adjusted within the process parameters to control the SO2 content in the gas exiting the tower, ensuring that ρ(SO2) < 100 mg / m³ in the gas discharged from the chimney. 3 Acid mist (p) less than 30 mg / m³ 3 .

[0064] Demineralized water is used to replenish the absorbent to prevent scale formation and calcium salt blockage of the nozzles inside the tower at temperatures above 45°C.

[0065] Oxidation treatment: After absorbing sulfur dioxide and sulfuric acid mist, the absorbent liquid, reaching a certain concentration, is sent to the oxidation tower through fiberglass pipes. At the same time, ammonia water is added to the oxidation tower to adjust the pH value of the solution to 4.5-5.5, so that the ammonium bisulfite in it is neutralized into ammonium sulfite. Compressed air at 100 m3 / h and 100 kPa and low-pressure saturated steam compressed air at 165℃, 0.55 MPa and 34 kg / h are introduced from the bottom of the tower. The compressed air comes into full contact with the heated absorbent liquid through the microporous aeration device at the bottom of the tower, so that the ammonium bisulfite and ammonium sulfite are oxidized into ammonium bisulfate and ammonium sulfate. The oxidation tower adopts perforated aeration oxidation technology.

[0066] The main reactions in the oxidation system are:

[0067] NH4HSO3 + NH3 → (NH4)2SO3

[0068] 2NH4HSO3 + O2 → 2NH4HSO4

[0069] 2(NH4)2SO3 + O2 → 2(NH4)2SO4

[0070] After oxidation, the qualified ammonium sulfate solution overflows from the top of the oxidation tower into the ammonium sulfate tank. Excess compressed air in the oxidation tower is sent to the absorption tower through the gas-liquid balance pipe and is finally discharged with the purified tail gas.

[0071] Sulfuric acid specific gravity control: After sulfonation, continuous dilution is carried out using seven reaction vessels. 22% mother liquor is added to the first vessel and the temperature is controlled. The mother liquor is added to the second dilution vessel, and the specific gravity of the acid is controlled within ±1.70.

[0072] During absorption treatment, the mass concentration of trace ammonia and large-particle water mist in the exhaust gas is ≤75mg / m³. 3 .

[0073] In controlling the specific gravity of sulfuric acid, the temperature is kept below 70℃.

[0074] By employing seven reaction vessels to treat the tail gas, and because this process continuously dilutes aminosulfonic acid sulfonates, it completely solves the problems of labor-intensive material transfer in existing technologies. The original intermittent dilution process was labor-intensive, costly, difficult to transfer, difficult to control, and inconvenient to operate. Therefore, the continuous dilution process provided by this technology is easy to operate, has low labor intensity for workers, high product yield, and good quality. At the same time, it can recover up to 60% concentration of sulfuric acid as a by-product for recycling, and most of the dilute sulfuric acid can be used, reducing the amount of waste sulfuric acid discharged.

[0075] Example 3:

[0076] A process for treating sulfuric acid emissions from aminosulfonic acid production includes the following treatment steps:

[0077] (1) The slurry in the ash trough is pumped to the dilute acid collection tank. The dilute acid collection tank is kept alkaline during the acid discharge period and is neutralized by circulating water.

[0078] (2) The plate and frame backflush reflux liquid and the Gore membrane sludge discharge liquid are recovered into the dilute acid collection tank through the pipeline.

[0079] (3) Resin pretreatment: Soak in 2BV 10% sodium chloride solution for 18-20 hours, rinse with clean water until the discharged water is not yellow, then soak in 2%-4% sodium hydroxide solution or 5% hydrochloric acid solution (the amount is the same as above) for 2-4 hours (or wash with a small flow rate), after draining the alkali or acid, rinse the resin until the water is close to neutral and ready for use.

[0080] (4) If the adsorption effect is not good after the macroporous resin has been used for more than 3 cycles, methanol can be used for elution.

[0081] The above optimized process for treating sulfuric acid plant wastewater has the following advantages:

[0082] 1) No water is added during the dilute acid neutralization and ash-making process. Calcium hydroxide treatment can precipitate some of the cations in the wastewater.

[0083] 2) The plate and frame filter and Gore membrane secondary filtration ensures that the pH value and suspended solids of the wastewater meet environmental protection requirements.

[0084] 3) By comparison, large-pore resin was selected to reduce the COD of wastewater. It has a good effect, no secondary pollution, and the use of dilute sulfuric acid produced by the sulfuric acid plant to wash the resin reduces the system operating cost. It can also enrich some organic matter in the wastewater and make it possible to recycle it.

[0085] 4) The treated wastewater meets or exceeds environmental standards and can be recycled, saving approximately 66,000-95,000 m³ of primary water. 3 / a.

[0086] Comparative Example 1:

[0087] Chemical treatment of COD is currently a conventional treatment method, characterized by convenient operation and rapid results. During the production process, the reaction speed of the COD degradation agent is very fast, which can be completed within 2-3 minutes. It can directly treat wastewater. Based on the site environment, it was decided to use it in the secondary sedimentation tank for enriching wastewater. The original wastewater COD was 714.1 mg / m3. Different amounts of COD degradation agent were added to the wastewater, and the COD values ​​of the treated wastewater are shown in the table below.

[0088] Processing Projects numerical values <![CDATA[Original sewage COD / (mg·m -3 )]]> 714.1 <![CDATA[After adding 1 g / L of the agent, the sewage COD / (mg·m -3 )]]> 601.8 <![CDATA[After adding 2 g / L of the agent, the sewage COD / (mg·m -3 )]]> 492.3 <![CDATA[After adding 3 g / L of the agent, the sewage COD / (mg.m -3 )]]> 396.7 <![CDATA[After adding 4 g / L of the reagent, the sewage COD / (mg.m -3 )]]> 309.5 <![CDATA[After adding 5 g / L of the reagent, the sewage COD / (mg.m -3 )]]> 197.6 <![CDATA[After adding 7 g / L of the reagent, the sewage COD / (mg·m -3 )]]> 110.6 <![CDATA[After adding 9 g / L of the reagent, the sewage COD / (mg.m -3 )]]> 42.6

[0089] Tests showed that when wastewater COD is high, the average dosage of the chemical method is 1 g / L, which can reduce COD by approximately 100 mg / m³. 3As the COD in wastewater decreases, the degradation effect gradually weakens.

[0090] Based on the current actual situation of wastewater from sulfuric acid plants, theoretical calculations are performed on 1m³ of wastewater. 3 9 kg of COD degradation agent needs to be added to the wastewater to meet the wastewater discharge requirements. 120 m³ of wastewater is treated daily. 3 The method requires the addition of 980 kg of reagents, resulting in high reagent consumption and costs. Furthermore, the treated wastewater cannot be reused after adding the reagents. Therefore, the reagent method is not suitable for treating low-concentration COD wastewater.

[0091] Finally, it should be noted that although the present invention has been described in detail above with general descriptions and specific embodiments, the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or substitutions can be made to some or all of the technical features; and these modifications or substitutions 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 process for treating sulfuric acid emissions for use in the production of aminosulfonic acid, characterized by, The process includes the following treatment processes: Absorption treatment: the tail gas absorption tower adopts a tower tank integrated structure. The sulfuric acid tail gas is introduced into the lower absorption section of the absorption tower through the flue gas pipeline. The tail gas flows from bottom to top in the absorption tower and is in contact with the upwardly sprayed absorption liquid. SO2 in the tail gas reacts with the absorption agent ammonia water in the absorption liquid to generate ammonium bisulfite and ammonium sulfite. At the same time, ammonium bisulfite and ammonia continue to react to generate ammonium sulfite. When the absorption liquid reaches a certain concentration, the sulfuric acid tail gas after SO2 removal is introduced into the upper demisting purification section of the absorption tower. Main reactions of the absorption system: NH3+H2O+SO2→NH4HSO3 2NH3+H2O+SO2→(NH4)2SO3 NH4HSO3+NH3→(NH4)2SO3 (NH4)2SO3+SO2+H2O→2NH4HSO3 SO3+H2O→H2SO4 The demisting purification section is provided with ammonia removal, water mist removal and gas aerosol removal devices. The tail gas containing trace amounts of ammonia and water mist after SO2 removal flows from bottom to top in the purification section. Through the impact of the tail gas on the demisting device and the gravity of the liquid droplets, the tail gas is captured and removed to obtain purified tail gas. The purified tail gas is introduced into the chimney for discharge. Control process index pH value in 5.0-6.0 operating liquid gas ratio 0.5-0.8 L / m 3 Circulating liquid density 1080-1160 kg / m 3 In the corresponding range, desulfurization efficiency can reach more than 94%, the biggest influence on desulfurization efficiency is ammonia water atomization effect and pH value, when designing, spiral nozzle is used to increase the contact area of ammonia water and flue gas, when producing, by adjusting pH value in the process index range, SO2 content in the gas out of the tower is controlled, so that ρ(SO2) in the exhaust chimney gas is less than 100 mg / m 3 Acid mist (p) is less than 30 mg / m 3 ; The absorption liquid supplement water uses desalted water to prevent the absorption liquid from scaling to form calcium salt to block the nozzles in the tower when the temperature is above 45℃. Oxidation treatment: the absorption liquid reaching a certain concentration after absorbing sulfur dioxide and sulfuric acid mist is sent to the oxidation tower through a glass steel pipeline. At the same time, ammonia water is added to the oxidation tower to adjust the pH value of the solution to 4.5-5.5 to neutralize the bisulfite in the solution into ammonium sulfite. 100 m3 / h, 100 kPa compressed air and 165℃, 0.55 MPa, 34 kg / h low-pressure saturated steam compressed air are introduced into the tower bottom microporous aeration device to fully contact with the heated absorption liquid to oxidize the bisulfite and ammonium sulfite into ammonium bisulfate and ammonium sulfate. The oxidation tower adopts a perforated aeration oxidation technology. Main reactions of the oxidation system: NH4HSO3+NH3→(NH4)2SO3 2NH4HSO3+O2→2NH4HSO4 2(NH4)2SO3+O2→2(NH4)2SO4 The qualified ammonium sulfate solution after oxidation is overflowed from the upper part of the oxidation tower to the ammonium sulfate liquid tank. The excess compressed air in the oxidation tower is sent to the absorption tower through a gas-liquid balance pipe and is finally discharged together with the purified tail gas. Sulfuric acid specific gravity control: after sulfonation, continuous dilution is performed. Seven reaction kettles are operated. 22% mother liquor is added to the first kettle, and the temperature is controlled. The mother liquor is supplemented in the second dilution kettle. The specific gravity of the acid is controlled within ±1.

70.

2. A process for treating sulfuric acid emissions for use in the production of sulfamic acid according to claim 1, characterized in that: In the absorption treatment, the mass concentration of trace ammonia and large-particle water mist in the tail gas is ≤75 mg / m 3 .

3. A process for treating sulfuric acid emissions for use in the production of sulfamic acid according to claim 1, characterized in that: In the sulfuric acid specific gravity control, the temperature is controlled within 70℃.

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