Process for producing electronic-grade sulfuric acid based on absorption and desorption of organic amine

Abstract

The invention discloses a process for producing electronic-grade sulfuric acid based on absorption and desorption of organic amine. The process comprises the following steps: treating SO2 flue gas containing other components through an organic amine absorption and desorption process to obtain SO2 saturated gas of which the products are pure SO2 and water; high-concentration SO2 gas can be obtained through condensation and gas-liquid separation; mixing with pure O2 and inert gas to obtain SO2 water-containing mixed gas; after drying, pressurizing and heating, carrying out multi-stage conversion to obtain SO3 mixed gas; circulating absorption of fuming sulfuric acid; evaporating and removing impurities to obtain high-purity SO3 gas with the purity of 99.99% or above; carrying out liquefaction rectification to obtain an ultra-pure SO3 liquid with the purity of 99.9999% or above; after being gasified into ultra-pure SO3 gas, the ultra-pure SO3 gas is mixed with ultra-pure inert gas to obtain electronic-grade sulfuric acid absorption gas; circularly absorbing electronic-grade sulfuric acid; and filtering and outputting finished electronic-grade sulfuric acid. According to the invention, the electronic-grade sulfuric acid and the chemical reagent sulfuric acid can be simultaneously produced, and the comprehensive cost of investment and operation is reduced by 10-20%.

Description

Technical Field

[0001] The present invention relates to the fields of chemical engineering, smelting and environmental protection technology, and in particular to the technical field of sulfuric acid production and desulfurization energy saving and ultra-low emission from SO2-containing flue gas generated by various furnaces and reactors. Specifically, it relates to a process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption. Background Art

[0002] Electronic-grade sulfuric acid, also known as high-purity sulfuric acid or ultra-pure sulfuric acid, is a key ultra-clean basic chemical reagent widely used in the assembly and processing of semiconductors and ultra-large-scale integrated circuits. It is primarily used for cleaning and etching silicon wafers, effectively removing impurity particles, inorganic residues, and carbon deposits on the wafers. With the further reduction of chip manufacturing processes and the development of new energy technologies (such as lithium batteries and hydrogen energy), the purity and application scenarios of electronic-grade sulfuric acid will continue to upgrade. Electronic-grade sulfuric acid is a high-end sulfuric acid product developed and introduced in recent years, and its application in the electronics industry and other fields has developed rapidly. The electronics industry is developing rapidly around the world, and Asia (especially China, South Korea, and Japan) is the global center of semiconductor and PCB manufacturing. The demand for electronic-grade sulfuric acid has surged, and the demand is growing.

[0003] Flue gas emitted from various furnaces or reactors in smelting, chemical, and other industries contains SO2. Flue gas with high SO2 concentrations is typically used to produce industrial-grade sulfuric acid. Flue gas with relatively low SO2 concentrations is typically concentrated and purified using organic amine absorption, after which it is used to produce liquid SO2 or returned to the sulfuric acid system for sulfuric acid production. Organic amine desulfurization, due to its unique selectivity in SO2 absorption, increases SO2 concentration while effectively separating it from other substances. This process, characterized by sulfur resource recovery and virtually no secondary pollution, has seen rapid adoption over the past decade. Currently, China has become the fastest-growing country in the world in terms of demand for IT and liquid crystal displays (LCDs). The competitiveness of Chinese companies is continuously increasing, and with significant long-term growth potential, it has become one of the fastest-growing and most dynamic sectors in the chemical industry. Demand for the accompanying ultra-clean, high-purity reagents is also steadily increasing. Electronic-grade sulfuric acid consumption accounts for approximately 30% of all high-purity reagents, posing a promising market demand. Currently, the production of electronic-grade sulfuric acid relies primarily on imported technology, with distillation and gas absorption being common methods of preparing it.

[0004] Rectification is a distillation method that uses reflux to achieve high-purity separation of liquid mixtures. Atmospheric distillation typically operates at temperatures as high as 330°C, requiring high-quality equipment. Vacuum distillation operates at temperatures between 175 and 190°C and pressures between 1.33 kPa and 2.67 kPa. Rectification consumes a lot of energy and is costly. Some impurities are difficult to remove, and the resulting waste gas and acid mist are harmful to humans and the environment, making it suitable only for small-scale production.

[0005] The gas absorption method is to obtain the super-pure fuming sulfuric acid by purifying the furnace gas, and the purified sulfur trioxide after the fuming sulfuric acid is evaporated to remove mist is directly absorbed by the super-pure water, and the purification of the sulfur trioxide is the key to reach the standard of the product.

[0006] The volatile impurities (such as HCl and NOx) are removed by multi-stage distillation, but the multi-stage distillation has low efficiency in removing the volatile impurities, is difficult, has a long process flow, unstable product quality, and high investment and operation cost, and thus is an urgent subject to be researched and broken through. SUMMARY

[0007] The present application aims at the problems existing in the prior art, and provides a process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption.

[0008] The present application is achieved by the following technical scheme:

[0009] A process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption, characterized in that the process steps are as follows:

[0010] A. SO2 flue gas containing other components is treated by the organic amine absorption and desorption process to obtain a product of pure SO2 and SO2 saturated gas containing water;

[0011] B. The SO2 saturated gas is condensed and gas-liquid separated to obtain high-concentration SO2 gas with a volume concentration of 80% to 95%;

[0012] C. The high-concentration SO2 gas, pure O2 and inert gas are mixed to obtain SO2 water-containing mixed gas with a volume concentration of 7% to 40%;

[0013] D. The SO2 water-containing mixed gas is dried by using concentrated sulfuric acid with a mass fraction of not less than 93% to obtain SO2 dehydrated mixed gas;

[0014] E. The SO2 dehydrated mixed gas is pressurized and heated, and then multi-stage conversion is carried out to obtain SO3 mixed gas containing SO3, excess O2, inert gas and a small amount of impurities;

[0015] F. The SO3 mixed gas is absorbed by fuming sulfuric acid in circulation;

[0016] G. The fuming sulfuric acid with a free SO3 content of 26% to 32% is sent into an SO3 evaporator to remove impurities by evaporation, and high-purity SO3 gas with a purity of not less than 99.99% is obtained;

[0017] H. The high-purity SO3 gas is subjected to liquefied rectification to obtain super-pure SO3 liquid with a purity of not less than 99.9999%;

[0018] I. The ultra-pure SO3 liquid gasified into ultra-pure SO3 gas is mixed with an ultra-pure inert gas to obtain an electronic grade sulfuric acid absorption gas;

[0019] J. The electronic grade sulfuric acid absorption gas is cyclically absorbed by electronic grade sulfuric acid;

[0020] K. The electronic grade sulfuric acid obtained by cyclic absorption is filtered by a filter, and the output product electronic grade sulfuric acid meets the national standard GB / T41881-2022.

[0021] The SO3 in the SO3 mixed gas in step F is 35% to 50% cyclically absorbed by oleum, and the SO3 mixed gas carrying the remaining SO3 is cyclically absorbed by chemical reagent sulfuric acid. The finished chemical reagent sulfuric acid obtained after the chemical reagent sulfuric acid cyclic absorption is output after cooling, and the tail gas composed of excess O2 and inert gas returns to step C to continue to participate in the cycle to form a relatively closed cycle system; the chemical reagent sulfuric acid cyclic absorption is supplemented with ultra-pure water.

[0022] The total SO3 absorption rate of SO3 in the SO3 mixed gas after the oleum cyclic absorption and the chemical reagent sulfuric acid cyclic absorption can reach 99.99%.

[0023] The finished chemical reagent sulfuric acid meets the national standard GB / T625.

[0024] The finished chemical reagent sulfuric acid obtained after the chemical reagent sulfuric acid cyclic absorption is transported to step D to participate in the drying of SO2 mixed gas and / or transported to step F to participate in the oleum cyclic absorption.

[0025] The SO2-containing flue gas in step A is SO2-containing flue gas containing impurities and volatile gases with a SO2 volume concentration of 0.1% to 7%. After the SO2-containing flue gas is subjected to adiabatic evaporation cooling and dust removal by a purification washing system, it enters the SO2 flue gas absorption tower for gas-liquid absorption reaction. The flue gas after SO2 removal meets the ultra-clean emission standard and is discharged into the chimney. The rich amine liquid that has absorbed SO2 in the SO2 flue gas absorption tower is heated by the secondary steam generated by the reboiler in the SO2 desorption tower to complete desorption, and the SO2 saturated gas (pure SO2 gas free of impurities and volatile gases) with a temperature of 90°C to 125°C is obtained.

[0026] It should be particularly noted that the SO2 gas in the flue gas is purified and volatile impurities (such as HF, HCl, NO x , etc.) are removed by taking advantage of the selective characteristics of the organic amine desulfurization process in step A.

[0027] The SO2 saturated gas discharged from the SO2 desorption tower does not contain other volatile gases.

[0028] The SO2 saturated gas in step B is first condensed and cooled to 40°C to 80°C for dehydration, and then subjected to gas-liquid separation and dehydration to obtain a high-concentration SO2 gas consisting of 80% to 95% SO2 and 20% to 5% water by volume; the high-concentration SO2 gas, pure O2 and inert gas in step C are mixed to obtain a SO2 water-containing mixed gas with a temperature of 50°C to 90°C, and the volume concentration of O2 in the SO2 water-containing mixed gas reaches 7% to 40%.

[0029] The supplementary source of concentrated sulfuric acid with a mass fraction of not less than 93% in step D is fuming sulfuric acid in step F or chemical reagent sulfuric acid. The output temperature of the SO2 dehydrated mixed gas in step D is 50°C to 120°C; the volume concentration of SO2 in the SO2 dehydrated mixed gas in step D is 12% to 40% (preferably 20% to 40%).

[0030] The pressurization in step E can obtain a SO2 pressurized mixed gas with a pressure of 25kPa~40kPa and a temperature of 70℃~170℃. After multi-stage heating, the SO2 pressurized mixed gas obtains a SO2 conversion mixed gas with a pressure of 22kPa~37kPa and a temperature of 380℃~450℃. After multi-stage conversion, the SO2 conversion mixed gas obtains a SO3 mixture with a pressure of 12kPa~27kPa and a temperature of 160℃~220℃. The total SO2 conversion rate after multi-stage conversion can reach 99.5%.

[0031] The SO2 pressurized mixed gas is subjected to a first-stage heating to obtain a SO2 first-stage heating mixed gas with a pressure of 24kPa~39kPa and a temperature of 200℃~300℃, and a second-stage heating to obtain a SO2 second-stage heating mixed gas with a pressure of 26kPa~38kPa and a temperature of 250℃~350℃, and a third-stage heating to obtain a SO2 conversion mixed gas with a pressure of 22kPa~37kPa and a temperature of 380℃~450℃; the SO2 conversion mixed gas is subjected to a first-stage conversion to output a first-stage conversion mixed gas with a pressure of 19kPa~34kPa and a temperature of 500℃~600℃, and the first-stage conversion mixed gas is subjected to a first-stage cooling to output a pressure of 18kPa~3 The first-stage cooling mixed gas has a pressure of 3kPa and a temperature of 410℃~460℃; the first-stage cooling mixed gas outputs a second-stage conversion mixed gas with a pressure of 16kPa~31kPa and a temperature of 450℃~550℃ after the second-stage conversion, and the second-stage conversion mixed gas outputs a second-stage cooling mixed gas with a pressure of 15kPa~30kPa and a temperature of 410℃~430℃ after the second-stage cooling; the second-stage cooling mixed gas outputs a third-stage conversion mixed gas with a pressure of 13kPa~28kPa and a temperature of 440℃~460℃ after the third-stage conversion, and the third-stage conversion mixed gas outputs a SO3 mixed gas with a pressure of 12kPa~27kPa and a temperature of 160℃~220℃ after the third-stage cooling.

[0032] The primary conversion is completed in a quasi-isothermal converter, and the secondary conversion and tertiary conversion are carried out step by step in a multi-stage converter, wherein the conversion rate of the primary conversion is 60% to 90%, the sum of the conversion rates of the secondary conversion and the tertiary conversion is 90% to 97%, and the sum of the conversion rates of the primary conversion, the secondary conversion and the tertiary conversion can reach 99.5%.

[0033] The process of adopting oleum for cyclic absorption of the SO3 gas mixture in the step F is as follows: the SO3 gas mixture at a pressure of 12kPa-27kPa and a temperature of 160°C-220°C is fed from the bottom of the oleum absorption tower and meets the oleum at a pressure of 100kPa-150kPa and a temperature of 50°C-60°C from top to bottom to be absorbed by the absorbed portion of SO3, the generated oleum at a temperature of 60°C-80°C is returned to the oleum circulation tank and is pressurized by the oleum circulation pump and cooled by the oleum cooler to a oleum at a pressure of 100kPa-150kPa and a temperature of 50°C-60°C, and continues to participate in the cyclic absorption, and the SO3 gas mixture containing the remaining portion of SO3 at a pressure of 9kPa-24kPa and a temperature of 80°C-130°C is transported to the chemical reagent sulfuric acid absorption tower for cyclic absorption.

[0034] The chemical reagent sulfuric acid absorption tower has the following cyclic absorption process: the SO3 mixed gas with a pressure of 9kPa to 24kPa and a temperature of 80℃ to 130℃ is introduced from the bottom of the chemical reagent sulfuric acid absorption tower and meets the chemical reagent sulfuric acid with a pressure of 100kPa to 150kPa and a temperature of 60℃ to 80℃ from top to bottom, and the remaining SO3 is absorbed to generate the atmospheric pressure chemical reagent sulfuric acid with a temperature of 70℃ to 100℃, which is returned to the chemical reagent sulfuric acid circulation tank and pressurized by the chemical reagent sulfuric acid circulation pump and cooled by the chemical reagent sulfuric acid cooler to the pressure of 100kPa to 150kPa and the temperature of 60℃ to 80℃. The acid continues to participate in the circulation absorption, and the tail gas composed of surplus O2 and inert gas with a pressure of 6kPa to 21kPa and a temperature of 70°C to 90°C outputted from the top of the chemical reagent sulfuric acid absorption tower returns to step C and continues to participate in the circulation; the chemical reagent sulfuric acid circulation tank is supplemented with ultrapure water through the ultrapure water inlet pipe to maintain the acid concentration balance, the chemical reagent sulfuric acid with a temperature of 70°C to 90°C in the chemical reagent sulfuric acid circulation tank is pressurized by the chemical reagent sulfuric acid circulation pump and cooled by the chemical reagent sulfuric acid cooler to a pressure of 100kPa to 150kPa and a temperature of 60°C to 80°C, and is output through the finished chemical reagent sulfuric acid output pipe.

[0035] The evaporation temperature of the SO3 evaporator in the step G is 90°C to 130°C. The oleum from the oleum circulation tank with a free SO3 content of 26% to 32% is pressurized to 100kPa to 150kPa by the oleum circulation pump and then input into the SO3 evaporator heated by low-pressure steam. After evaporation and impurity removal, high-purity SO3 gas with a pressure of 20kPa to 50kPa and a temperature of 90°C to 140°C is obtained. The oleum from the oleum circulation tank is evaporated to obtain normal-pressure oleum with a temperature of 90°C to 110°C and a free SO3 content of 20% to 23%, which is returned to the oleum circulation tank.

[0036] The evaporation process of the SO3 evaporator in step G can remove the entrained trace heavy metals and dust. The SO3 gas evaporated from the SO3 evaporator passes through a demister, and then the demister removes the entrained trace sulfuric acid to obtain high-purity SO3 gas with a purity of more than 99.99%; the entrained trace sulfuric acid can return to the drying sulfuric acid absorption tower to participate in the drying process.

[0037] The high-purity SO3 gas in step H enters a SO3 condenser at a temperature of 30°C to 50°C for liquefaction and distillation (other non-condensable gases are removed by distillation based on their different properties from other non-condensable gases), and the ultra-pure SO3 liquid with a pressure of 0kPa to 1kPa, a temperature of 20°C to 35°C and a purity of more than 99.9999% is obtained and sent to a liquid SO3 storage tank for storage; the gaseous reducing gas (such as SO2 gas) generated by the liquefaction and distillation is returned to the gas mixing device in step C through a pipeline with a valve provided on the SO3 condenser or the liquid SO3 storage tank.

[0038] The ultrapure SO3 liquid in step I is fed into a SO3 vaporizer with a vaporization temperature of 50°C to 80°C. The SO3 vaporizer heated by low-pressure steam outputs ultrapure SO3 gas with a pressure of 10kPa to 15kPa and a temperature of 60°C to 80°C. The electronic-grade sulfuric acid absorption gas obtained by mixing the ultrapure SO3 gas with an ultrapure inert gas is fed into an electronic-grade sulfuric acid absorption tower; the residual liquid generated by the SO3 vaporizer is transported to a fuming sulfuric acid circulation tank to participate in SO3 absorption.

[0039] The volume ratio of the ultrapure SO3 gas to the ultrapure inert gas in step I is 70% to 40%:30% to 60%.

[0040] The purity of the ultrapure inert gas in step I is above 99.999%.

[0041] The process of the electronic-grade sulfuric acid circulation absorption in step J is as follows: the electronic-grade sulfuric acid absorption gas is introduced from the bottom of the electronic-grade sulfuric acid absorption tower into the electronic-grade sulfuric acid at a pressure of 10kPa-15kPa and a temperature of 60°C-80°C from top to bottom and is absorbed, generating normal-pressure electronic-grade sulfuric acid at a temperature of 70°C-100°C, which is returned to the electronic-grade sulfuric acid circulation tank and pressurized by the electronic-grade sulfuric acid circulation pump and cooled by the cluster heat exchanger to electronic-grade sulfuric acid at a pressure of 10kPa-15kPa and a temperature of 60°C-80°C, which continues to participate in the circulation absorption, and the inert gas outputted from the top of the electronic-grade sulfuric acid absorption tower at a pressure of 6kPa-11kPa and a temperature of 70°C-90°C is returned to step C to continue to participate in the circulation, so that no tail gas is emitted; the electronic-grade sulfuric acid circulation tank is supplemented with electronic-grade ultrapure water through the electronic-grade ultrapure water inlet pipe to maintain acid concentration balance.

[0042] The absorption rate of the ultra-pure SO3 gas in the absorption gas of the electronic-grade sulfuric acid in step J can reach 99.99%.

[0043] During the electronic-grade sulfuric acid circulation absorption in step J, the mass concentration of the circulating electronic-grade sulfuric acid in the electronic-grade sulfuric acid circulation tank is 95% to 98.6%, and the purity of the electronic-grade ultrapure water used is 99.9999wt%.

[0044] The electronic-grade sulfuric acid in step K is pressurized by an electronic-grade sulfuric acid circulation pump and cooled by a cluster heat exchanger to a pressure not higher than 100 kPa and a temperature not higher than 40° C., and then sent to a filter with a membrane pore size of 0.1 μm to 1 μm for 1 to 3 stages of filtration to obtain finished electronic-grade sulfuric acid. The finished electronic-grade sulfuric acid is output through an electronic-grade sulfuric acid output pipe to an electronic-grade sulfuric acid storage tank for nitrogen-sealed storage.

[0045] The gas in steps B to J can be circulated in a closed manner to achieve zero emission.

[0046] It should be noted that the quality of electronic-grade sulfuric acid specified in the national standard GB / T41881-2022 is from high to low: E1, E2, E3, E4, and E5 (corresponding to G5, G4, G3, G2, and G1 in the levels of the International Semiconductor Industry Association SEMI, respectively, among which the E5-level indicators are basically the same as the G1-level indicators, and the E1-level indicators are basically the same as the G5-level indicators). The finished electronic-grade sulfuric acid obtained by the process provided by the present invention can reach the highest level of E1 and will not be lower than E5.

[0047] The pressures mentioned in the process provided by the present invention are all gauge pressures.

[0048] Compared with the prior art, the present invention has the following advantages:

[0049] The present invention purifies SO2 by using organic amine absorption and desorption technology to remove volatile impurities. Pure oxygen is then used to react with high-concentration SO2 to produce fuming sulfuric acid and chemical reagent sulfuric acid. The fuming sulfuric acid is then evaporated to produce SO3, and the SO3 is condensed and distilled to remove reducing substances. Finally, in a clean environment, the concentrated electronic-grade sulfuric acid is balanced with electronic-grade ultrapure water to absorb the ultrapure SO3 to produce an ultrapure sulfuric acid product that meets the GB / T41881-2022 standard. This process can simultaneously produce ultrapure sulfuric acid and chemical reagent sulfuric acid, with stable and reliable product quality, and reduces the overall investment and operating costs by 10%-20%. It can also achieve zero flue gas emissions.

[0050] The process of the present invention utilizes the characteristic that the organic amine absorbent only selects SO2 for adsorption, and its characteristic is that it can selectively adsorb SO2 gas in the flue gas, while other media (NO x , HF, HCl, etc.) are retained in the flue gas and discharged after being processed together with the flue gas; through this process, the purpose of purifying and then concentrating SO2 gas is achieved, and the problem of removing volatile gases by distillation is solved.

[0051] The process of the present invention utilizes purified high-concentration SO2 gas, which is mixed with pure oxygen and inert gas to produce a pure SO3 mixed gas. The SO3 mixed gas enters an ultra-pure fuming sulfuric acid absorption tower to obtain fuming sulfuric acid (preventing other substances from entering the system). After being absorbed by the fuming sulfuric acid absorption tower, the SO3 mixed gas enters a chemical reagent sulfuric acid absorption tower to absorb the remaining SO3 gas. Ultra-pure water is added to the chemical reagent sulfuric acid circulation tank to maintain the acid concentration balance while producing chemical reagent sulfuric acid.

[0052] The process of the present invention utilizes fuming sulfuric acid to evaporate to obtain high-purity SO3 gas, which is then liquefied and distilled through a SO3 condenser to obtain ultra-pure SO3 liquid. The liquefaction and distillation removes reducing gases based on the difference in boiling points to complete the liquefaction and distillation process.

[0053] The process of the present invention heats and vaporizes ultrapure SO3 liquid, and the ultrapure SO3 gas generated after the heating and vaporization is mixed with the introduced ultrapure inert gas and then enters an electronic-grade sulfuric acid absorption tower. The electronic-grade sulfuric acid absorption tower directly absorbs the electronic-grade sulfuric acid that can be supplemented with electronic-grade ultrapure water. The absorbed electronic-grade sulfuric acid is filtered through 1 to 3 stages (with a filter membrane pore size of 0.1 to 1 μm) to obtain finished electronic-grade sulfuric acid. The finished electronic-grade sulfuric acid is fed into a fluoropolymer-lined electronic-grade sulfuric acid storage tank through an electronic-grade sulfuric acid output pipe to obtain an ultrapure sulfuric acid product (meeting the GB / T41881-2022 standard).

[0054] The present invention purifies the raw gas SO2 through organic amines, and through the process of fuming sulfuric acid distillation, SO3 liquefaction rectification, and electronic-grade sulfuric acid absorption with electronic-grade ultrapure water, can produce electronic-grade sulfuric acid on a large scale and simultaneously co-produce chemical reagent sulfuric acid. The present invention has the advantages of a short process flow, no secondary pollution, ultra-clean emissions, scalable and automated equipment, and a 20%-40% reduction in overall investment and operation costs, and is therefore suitable for popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Attachment Figure 1 The present invention provides a process flow chart for producing electronic-grade sulfuric acid based on organic amine absorption and desorption.

[0056] Among them: 1 - SO2 flue gas absorption tower; 2 - lean and rich amine heat exchanger; 3 - SO2 desorption tower; 4 - pure oxygen supply pipe; 5 - gas mixing device; 6 - flue gas drying tower; 7 - SO2 booster fan; 8 - primary heat exchanger; 9 - multi-stage converter; 10 - oleum absorption tower; 11 - oleum cooler; 12 - oleum circulation pump; 13 - niacin inlet pipe for evaporator; 14 - chemical reagent sulfuric acid absorption tower; 15 - ultrapure water inlet pipe; 16 - chemical reagent sulfuric acid circulation pump; 17 - chemical reagent sulfuric acid cooler; 18 - finished chemical reagent sulfuric acid inlet Outlet pipe; 19—ultra-pure SO3 gas output pipe; 20—electronic-grade sulfuric acid absorption tower; 21—electronic-grade ultra-pure water input pipe; 22—electronic-grade sulfuric acid circulation pump; 23—clustered heat exchanger; 24—filter; 25—electronic-grade sulfuric acid output pipe; 26—SO3 vaporizer; 27—liquid SO3 storage tank; 28—SO3 condenser; 29—SO3 evaporator; 30—waste heat boiler; 31—quasi-isothermal pre-converter; 32—tertiary heat exchanger; 33—secondary heat exchanger; 34—SO2 vapor-liquid separator; 35—SO2 condenser; 36—chimney. DETAILED DESCRIPTION

[0057] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, but not all of the embodiments.

[0058] like Figure 1The process flow chart of producing electronic grade sulfuric acid based on organic amine absorption and desorption is shown. The devices used in the process include SO2 flue gas absorption tower 1, lean and rich amine heat exchanger 2, SO2 desorption tower 3, pure O2 supplement pipe 4, gas mixing device 5, flue gas drying tower 6, SO2 booster fan 7, primary heat exchanger 8, multi-stage converter 9, oleum absorption tower 10, oleum cooler 11, oleum circulation pump 12, evaporator nicotinic acid inlet pipe 13, chemical reagent sulfuric acid absorption tower 14, ultrapure water inlet pipe 15, chemical reagent sulfuric acid circulation pump 16, chemical reagent sulfuric acid Acid cooler 17, finished chemical reagent sulfuric acid output pipe 18, ultra-pure SO3 gas output pipe 19, electronic-grade sulfuric acid absorption tower 20, electronic-grade ultra-pure water input pipe 21, electronic-grade sulfuric acid circulation pump 22, cluster heat exchanger 23, filter 24, electronic-grade sulfuric acid output pipe 25, SO3 vaporizer 26, liquid SO3 storage tank 27, SO3 condenser 28, SO3 evaporator 29, waste heat boiler 30, quasi-isothermal pre-converter 31, tertiary heat exchanger 32, secondary heat exchanger 33, SO2 vapor-liquid separator 34, SO2 condenser 35, chimney 36. The SO2 desorption tower 3 is made of 316L stainless steel; the gas mixing device 5, the first-stage heat exchanger 8, the conventional converter 9, the quasi-isothermal pre-converter 31, the third-stage heat exchanger 32, and the second-stage heat exchanger 33 are all made of S30408 ​​stainless steel; the fuming sulfuric acid absorption tower 10 and the chemical reagent sulfuric acid absorption tower 14 are made of steel-lined F4 material, the fuming sulfuric acid cooler 11 and the chemical reagent sulfuric acid cooler 17 are made of Hastelloy; the fuming sulfuric acid circulation pump 12 and the chemical reagent sulfuric acid circulation pump 16 are fluoroplastic-lined magnetic pumps; the SO3 vaporizer 26. Liquid SO3 storage tank 27 and SO3 condenser 28 are made of 304L or 316L materials; electronic-grade sulfuric acid absorption tower 20 is lined with S30408 ​​ultra-pure PTFE, and the filler is ultra-pure PFA ball ring; the cluster heat exchanger 23 is made of ultra-pure PFA material; the electronic-grade sulfuric acid circulation pump 22 is an ultra-pure PFA magnetic pump; the filter 24 is lined with S30408 ​​ultra-pure PTFE and is equipped with an ultra-pure PFA / PTFE membrane filter element; the pipes and valves required for the process are S30408 ​​stainless steel lined with ultra-pure PTFE.

[0059] The connection relationship of the device is as follows: SO2-containing flue gas emitted by various kilns or reactors such as smelting and chemical industries is input from the bottom of the SO2 flue gas absorption tower 1 after adiabatic evaporation cooling and dust removal in the purification and washing system. The rich amine liquid output pipe at the bottom of the SO2 flue gas absorption tower 1 is connected to the liquid distributor above the packing layer in the middle of the SO2 desorption tower 3 through the lean-rich amine heat exchanger 2, and the lean amine liquid output pipe at the bottom of the SO2 desorption tower 3 is connected to the liquid distributor above the middle and upper packing layer of the SO2 flue gas absorption tower 1 through the lean-rich amine heat exchanger 2. A chimney 36 is provided on the top of the SO2 flue gas absorption tower 1 (this is also the only place with exhaust flue gas in the process provided by the present invention, and the gas generated in the subsequent process flow is recycled); the top of the SO2 desorption tower 3 is connected to the SO2 The condenser 35 and the SO2 condenser 35 are connected to the SO2 vapor-liquid separator 34 through a pipeline. The top of the SO2 vapor-liquid separator 34 is connected to the mixing device 5 through a pipeline, and the bottom of the SO2 vapor-liquid separator 34 is connected to the liquid distributor above the upper packing layer of the SO2 desorption tower 3 through a pipeline; the mixing device 5 is connected to the pure O2 replenishing pipe 4, and the mixing device 5 is also connected to the top of the chemical reagent sulfuric acid absorption tower 14 and the electronic grade sulfuric acid absorption tower 20 through pipelines to replenish inert gas. If needed, the mixing device 5 can also be connected to the inert gas supply device; the mixing device 5 is connected to the lower part of the flue gas drying tower 6 through a pipeline, and the top of the flue gas drying tower 6 is connected to the SO2 booster fan 7 through a pipeline, and the bottom of the flue gas drying tower 6 is connected to the configuration through a pipeline. The dry sulfuric acid circulation tank of the dry sulfuric acid circulation pump is connected to the dry sulfuric acid cooler through a pipeline, and the dry sulfuric acid cooler is connected to the liquid distributor above the packing layer in the flue gas drying tower 6 through a pipeline. The dry sulfuric acid circulation tank can also be connected to the fuming sulfuric acid circulation tank and the chemical reagent sulfuric acid circulation tank to replenish dry sulfuric acid; the SO2 booster fan 7 is connected to the quasi-isothermal pre-converter 31 through a pipeline in sequence through the first-stage heat exchanger 8, the second-stage heat exchanger 33, and the third-stage heat exchanger 32. The quasi-isothermal pre-converter 31 is equipped with a waste heat boiler 30. The pipeline at the bottom of the quasi-isothermal pre-converter 31 is connected to the second layer of the multi-stage converter 9 through the third-stage heat exchanger 32, and the pipeline at the bottom of the second layer of the multi-stage converter 9 is connected to the multi-stage converter through the second-stage heat exchanger 33. 9, and a pipeline at the bottom of a layer of the multi-stage converter 9 is connected to the lower part of the oleum absorption tower 10 through the primary heat exchanger 8; the top of the oleum absorption tower 10 is connected to the chemical reagent sulfuric acid absorption tower 14 through a pipeline, and the bottom of the oleum absorption tower 10 is connected to the oleum circulation tank configured with an oleum circulation pump 12 through a pipeline, the oleum circulation pump 12 is connected to the oleum cooler 11 through a pipeline, and the oleum cooler 11 is connected to the liquid distributor above the packing layer in the oleum absorption tower 10 through a pipeline, a demister is also arranged above the liquid distributor in the oleum absorption tower 10, and the oleum circulation tank can also be connected to the chemical reagent sulfuric acid circulation tank and the SO3 vaporizer 26 to replenish the oleum used for circulation;The top of the chemical reagent sulfuric acid absorption tower 14 is connected to the mixing device 5 through a pipeline, and the bottom of the chemical reagent sulfuric acid absorption tower 14 is connected to the chemical reagent sulfuric acid circulation tank equipped with a chemical reagent sulfuric acid circulation pump 16 through a pipeline. The chemical reagent sulfuric acid circulation pump 16 is connected to the chemical reagent sulfuric acid cooler 17 through a pipeline, and the chemical reagent sulfuric acid cooler 17 is connected to the liquid distributor above the packing layer in the chemical reagent sulfuric acid absorption tower 14 through a pipeline. A demister is also arranged above the liquid distributor in the chemical reagent sulfuric acid absorption tower 14. An ultrapure water inlet pipe 15 is arranged on the chemical reagent sulfuric acid circulation tank to supplement the ultrapure water to balance the acid concentration. A finished chemical reagent sulfuric acid output pipe 18 with a valve is arranged on the pipeline between the oleum circulating pump 12 and the oleum cooler 11; an evaporator nicotinic acid input pipe 13 with a valve is arranged on the pipeline between the oleum circulating pump 12 and the oleum cooler 11, the evaporator nicotinic acid input pipe 13 is connected to the SO3 evaporator 29 and the SO3 evaporator 29 is connected to the oleum circulating tank through a reflux pipe, and the SO3 evaporator 29 equipped with low-pressure steam is connected to the SO3 condenser 28 through a pipeline (a demister can be arranged on the pipeline between the two, and the trace sulfuric acid collected by the demister is returned to the drying sulfuric acid absorption tower 6 to participate in the drying Drying process); SO3 condenser 28 is connected to liquid SO3 storage tank 27 through a pipeline; liquid SO3 storage tank 27 is connected to the upper part (SO3 vaporizer 26 has a built-in sinking pipe) or the lower part of SO3 vaporizer 26 through a pipeline, and the top of SO3 vaporizer 26 equipped with low-pressure steam is connected to the lower part of electronic-grade sulfuric acid absorption tower 20 through ultra-pure SO3 gas output pipe 19 and the ultra-pure SO3 gas output pipe 19 is matched with an ultra-pure inert gas input pipe; the top of electronic-grade sulfuric acid absorption tower 20 is connected to gas mixing device 5 through a pipeline and the bottom of electronic-grade sulfuric acid absorption tower 20 is connected to electronic-grade sulfuric acid configured with electronic-grade sulfuric acid circulation pump 22 through a pipeline. The electronic-grade sulfuric acid circulation tank and electronic-grade sulfuric acid circulation pump 22 are connected to a cluster heat exchanger 23 via a pipeline. The cluster heat exchanger 23 is also connected to the liquid distributor above the packing layer in the electronic-grade sulfuric acid absorption tower 20 via a pipeline. A demister is also located above the liquid distributor in the electronic-grade sulfuric acid absorption tower 20. The electronic-grade sulfuric acid circulation tank is equipped with an electronic-grade ultrapure water inlet pipe 21 to replenish the electronic-grade ultrapure water to balance the acid concentration. A valved pipe is located between the cluster heat exchanger 23 and the liquid distributor in the electronic-grade sulfuric acid absorption tower 20, leading to a filter 24. The outlet of the filter 24 is connected to the electronic-grade sulfuric acid storage tank via an electronic-grade sulfuric acid outlet pipe 25. The above pipes are equipped with valves as needed.

[0060] The key technologies for high-level E1 and E2 electronic-grade sulfuric acid products are ultra-pure production equipment and a clean control environment. This device can produce chemical reagent sulfuric acid and electronic-grade sulfuric acid regardless of the concentration of SO2 flue gas while meeting ultra-clean emission standards.

[0061] A process flow chart for producing electronic grade sulfuric acid based on organic amine absorption and desorption is shown in the following figure: Figure 1 As shown, the process steps are as follows:

[0062] A. SO2-containing flue gas with a SO2 volume concentration of 0.1% to 7% and containing impurities and volatile gases passes through a purification and washing system to complete adiabatic evaporation cooling and dust removal, and then enters the SO2 flue gas absorption tower 1 for gas-liquid absorption reaction. After the SO2 is removed, the flue gas reaches the ultra-clean emission standard and enters the chimney 36 for discharge. The rich amine liquid that absorbs SO2 in the SO2 flue gas absorption tower 1 is heated by the lean-rich amine heat exchanger 2 and then enters the SO2 desorption tower 3. The rich amine liquid is desorbed in the SO2 desorption tower 3 by heating with secondary steam generated by the reboiler, and the product is pure SO2 and water with a SO2 saturated gas temperature of 90℃ to 125℃.

[0063] B. The SO2 saturated gas is first condensed and cooled to 40℃~80℃ for dehydration, and then subjected to gas-liquid separation and dehydration to obtain a high-concentration SO2 gas consisting of 80%~95% SO2 and 20%~5% water by volume;

[0064] C. High-concentration SO2 gas, pure O2 and inert gas are mixed to obtain a SO2 water-containing mixed gas at a temperature of 50°C to 90°C, wherein the volume concentration of SO2 in the SO2 water-containing mixed gas reaches 7% to 40%, and the volume concentration of O2 reaches 7% to 40%;

[0065] D. drying the SO2 water-containing mixed gas with a mass fraction of not less than 93% concentrated sulfuric acid to obtain a SO2 dehydrated mixed gas at a temperature of 50°C to 120°C, wherein the SO2 volume concentration in the SO2 dehydrated mixed gas is 12% to 40%, preferably 20% to 40%;

[0066] E. The SO2 dehydrated mixed gas can be pressurized to obtain a SO2 pressurized mixed gas with a pressure of 25kPa to 40kPa and a temperature of 70℃ to 170℃. The SO2 pressurized mixed gas is subjected to multi-stage temperature increase to obtain a SO2 converted mixed gas with a pressure of 22kPa to 37kPa and a temperature of 380℃ to 450℃. The SO2 converted mixed gas is subjected to multi-stage conversion to obtain a SO3 mixed gas with a pressure of 12kPa to 27kPa and a temperature of 160℃ to 220℃. The composition of the SO3 mixed gas is SO3, excess O2, inert gas and a small amount of impurities. The total SO2 conversion rate after multi-stage conversion can reach 99.5%;

[0067] F. The SO3 mixed gas with a pressure of 12kPa to 27kPa and a temperature of 160°C to 220°C is introduced from the bottom of the oleum absorption tower 10 and meets the oleum with a pressure of 100kPa to 150kPa and a temperature of 50°C to 60°C from top to bottom, and part of the SO3 is absorbed to generate oleum with a temperature of 60°C to 80°C. The oleum is returned to the oleum circulation tank and pressurized by the oleum circulation pump 12 and cooled by the oleum cooler 11 to oleum with a pressure of 100kPa to 150kPa and a temperature of 50°C to 60°C. Continuously participate in the cycle absorption; SO3 in the SO3 mixed gas is absorbed by the fuming sulfuric acid in a cycle of 35% to 50%, and the SO3 mixed gas containing the remaining part of SO3 with a pressure of 9kPa to 24kPa and a temperature of 80℃ to 130℃ is transported to the chemical reagent sulfuric acid absorption tower 14 for cycle absorption; the SO3 mixed gas with a pressure of 9kPa to 24kPa and a temperature of 80℃ to 130℃ is introduced from the bottom of the chemical reagent sulfuric acid absorption tower 14 and meets the chemical reagent sulfuric acid with a pressure of 100kPa to 150kPa and a temperature of 60℃ to 80℃ from top to bottom. The remaining part of SO3 is absorbed to generate atmospheric pressure chemical reagent sulfuric acid with a temperature of 70°C to 100°C, which is returned to the chemical reagent sulfuric acid circulation tank and pressurized by the chemical reagent sulfuric acid circulation pump 16 and cooled by the chemical reagent sulfuric acid cooler 17 to a pressure of 100kPa to 150kPa and a temperature of 60°C to 80°C for continued circulation absorption. The tail gas composed of surplus O2 and inert gas with a pressure of 6kPa to 21kPa and a temperature of 70°C to 90°C outputted from the top of the chemical reagent sulfuric acid absorption tower 14 is returned to step C for continued circulation. The reagent sulfuric acid circulation tank is supplemented with ultrapure water through the ultrapure water inlet pipe 15 to maintain the acid concentration balance. The chemical reagent sulfuric acid in the chemical reagent sulfuric acid circulation tank is pressurized at a temperature of 70°C to 90°C by the chemical reagent sulfuric acid circulation pump 16 and cooled by the chemical reagent sulfuric acid cooler 17 to a pressure of 100kPa to 150kPa and a temperature of 60°C to 80°C, and then output through the finished chemical reagent sulfuric acid output pipe 18. The total SO3 absorption rate of the SO3 mixed gas after the oleum and chemical reagent sulfuric acid circulation absorption can reach 99.99%.

[0068] G. The oleum with a free SO3 content of 26% to 32% in the oleum circulation tank is pressurized to 100kPa to 150kPa by the oleum circulation pump 12 and then fed into the SO3 evaporator 29 through the evaporator nicotinic acid inlet pipe 13. The SO3 evaporator 29, which is heated by low-pressure steam, evaporates and removes impurities from the oleum with a free SO3 content of 26% to 32% to obtain SO3 gas with a pressure of 20kPa to 50kPa and a temperature of 90°C to 140°C. The fuming sulfuric acid with a free SO3 content of 26% to 32% is reduced to a normal pressure fuming sulfuric acid with a free SO3 content of 20% to 23% and a temperature of 90°C to 110°C after SO3 evaporation, and then returns to the fuming sulfuric acid circulation tank; the evaporation process of the SO3 evaporator 29 can remove trace heavy metals and dust carried by the fuming sulfuric acid. The SO3 gas evaporated from the SO3 evaporator 29 passes through a demister to remove trace sulfuric acid carried by the fuming sulfuric acid, and then obtains high-purity SO3 gas with a purity of more than 99.99%;

[0069] H. The high-purity SO3 gas enters the SO3 condenser 28 at a temperature of 30°C to 50°C for liquefaction and rectification (due to the different properties of the gas from other non-condensable gases, the other non-condensable gases are removed by rectification). The ultra-pure SO3 liquid with a pressure of 0kPa to 1kPa, a temperature of 20°C to 35°C, and a purity of 99.9999% or more is obtained and sent to the liquid SO3 storage tank 27 for storage. The gaseous reducing gas (such as SO2 gas) produced by the liquefaction and rectification returns to the gas mixing device 5 in step C via the SO3 condenser 28 or a pipeline with a valve provided on the liquid SO3 storage tank 27.

[0070] I. Ultrapure SO3 liquid is fed into a SO3 vaporizer 26 with a vaporization temperature of 50°C to 80°C. The SO3 vaporizer 26, heated by low-pressure steam, outputs ultrapure SO3 gas at a pressure of 10kPa to 15kPa and a temperature of 60°C to 80°C. The electronic-grade sulfuric acid absorption gas obtained by mixing the ultrapure SO3 gas with an ultrapure inert gas is fed into an electronic-grade sulfuric acid absorption tower 20. The residual liquid produced by the SO3 vaporizer 26 is transported to a fuming sulfuric acid circulation tank to participate in SO3 absorption.

[0071] J. Electronic grade sulfuric acid absorption gas is introduced from the bottom of the electronic grade sulfuric acid absorption tower 20 and meets the electronic grade sulfuric acid at a pressure of 10kPa to 15kPa and a temperature of 60°C to 80°C from top to bottom and is absorbed to generate normal pressure electronic grade sulfuric acid at a temperature of 70°C to 100°C. It returns to the electronic grade sulfuric acid circulation tank and is pressurized by the electronic grade sulfuric acid circulation pump 22 and cooled by the cluster heat exchanger 23 to the electronic grade sulfuric acid at a pressure of 10kPa to 15kPa and a temperature of 60°C to 80°C. It continues to participate in the The inert gas outputted from the top of the electronic-grade sulfuric acid absorption tower 20 with a pressure of 6kPa to 11kPa and a temperature of 70°C to 90°C is returned to step C to continue to participate in the cycle, so that no tail gas is discharged; the electronic-grade sulfuric acid circulation tank is supplemented with electronic-grade ultrapure water through the electronic-grade ultrapure water inlet pipe 21 to maintain the acid concentration balance, the purity of the electronic-grade ultrapure water is 99.9999wt%, and the absorption rate of ultrapure SO3 gas in the electronic-grade sulfuric acid absorption gas can reach 99.99%;

[0072] K. After being pressurized by the electronic-grade sulfuric acid circulation pump 22 and cooled by the cluster heat exchanger 23 to a pressure not higher than 100 kPa and a temperature not higher than 40°C, the electronic-grade sulfuric acid is sent to the filter 24 with a pore size of 0.1 μm to 1 μm for 1 to 3 stages of filtration to obtain the finished electronic-grade sulfuric acid. The finished electronic-grade sulfuric acid is output through the electronic-grade sulfuric acid output pipe 25 to the electronic-grade sulfuric acid storage tank for nitrogen-sealed storage. The finished electronic-grade sulfuric acid complies with the national standard GB / T41881-2022.

[0073] The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption provided by the present invention is further described below in combination with the device used in the process provided by the present invention.

[0074] SO2-containing flue gas emitted from various kilns or reactors such as those in smelting and chemical industries undergoes adiabatic evaporation cooling and dust removal in a purification and washing system before entering a SO2 flue gas absorption tower 1. The flue gas undergoes a gas-liquid absorption reaction with the lean amine liquid from top to bottom on the surface of the filler. After the SO2 is removed, the flue gas reaches the ultra-clean emission standard and enters a chimney 36 for discharge. The rich amine liquid that has absorbed SO2 in the SO2 flue gas absorption tower 1 is heated to 97°C by the lean-rich amine heat exchanger 2 and then sent to the SO2 desorption tower 3. In the SO2 desorption tower 3, desorption is completed by heating with secondary steam generated by a reboiler (the heat source is low-pressure steam). The desorbed SO2 saturated gas enters the condenser 35 and the SO2 vapor-liquid separator 34 in sequence, obtaining a high-concentration SO2 gas consisting of SO2 with a volume concentration of 90% and 10% water at a temperature of 45°C. This achieves the goal of purifying and concentrating the SO2 gas and solves the problem of removing volatile gases by distillation.

[0075] The high-concentration SO2 gas produced by the SO2 vapor-liquid separator 34 is mixed with the pure O2 supplementary pipe 4 and the N2 returned from the chemical reagent sulfuric acid absorption tower 14 and / or the electronic grade sulfuric acid absorption tower 20 to obtain a SO2 water-containing mixed gas with a temperature of 50°C to 90°C. The SO2 concentration in the SO2 water-containing mixed gas is 30% (V / V%), the O2 concentration is 25% (V / V%), and the rest is N2 and water. The SO2 water-containing mixed gas enters the flue gas drying tower 6 and is countercurrently contacted with the sprayed 95% dry sulfuric acid. After drying, a SO2 dehydrated mixed gas with a temperature of 50°C to 120°C is obtained. The SO2 dehydrated mixed gas is pressurized to 25kPa to 40kPa by the SO2 booster fan 7 and then enters the first-stage heat exchanger 8 to exchange heat with the third-stage converted mixed gas at the first-layer outlet of the multi-stage converter 9. The SO2 first-stage heated mixed gas after heat exchange enters the second-stage heat exchanger 33 to exchange heat with the second-layer outlet of the multi-stage converter 9. The converted mixed gas undergoes heat exchange, and the SO2 secondary temperature-elevated mixed gas after heat exchange enters the tertiary heat exchanger 32 for heat exchange with the primary converted mixed gas at the outlet of the quasi-isothermal pre-converter 31. After three heat exchanges, the temperature of the SO2 converted mixed gas reaches 400°C, and then enters the quasi-isothermal pre-converter 31 for primary conversion reaction. The temperature of the primary converted mixed gas at the outlet of the quasi-isothermal pre-converter 31 will rise, and after heat recovery in the waste heat boiler 30 and heat exchange in the tertiary heat exchanger 32, it is cooled to 425°C and then enters the second layer of the multi-stage converter 9; after the reaction in the second layer of the multi-stage converter 9, the temperature of the secondary converted mixed gas increases and enters the secondary heat exchanger 33. After the temperature drops to 415°C, it enters the first layer of the multi-stage converter 9 for conversion reaction; after the reaction in the first layer of the multi-stage converter 9, the tertiary converted mixed gas enters the first heat exchanger 8, and the SO3 mixed gas whose temperature drops to 170°C after heat exchange is sent to the fuming sulfuric acid absorption tower 10.

[0076] Oleum absorption tower 10 is finished the oleum circulation by oleum recycle pump 12 and oleum water cooler 11, and the oleum in the oleum circulation groove can replenish the consumption in the dry sulfuric acid circulation groove, and the oleum in the oleum recycle groove replenishes the source and is chemical reagent sulfuric acid circulation groove and / or SO Vaporizer 26, SO Gas mixture is through oleum absorption tower 10 circulating acid absorption parts SO After, the SO of remainder Gas mixture enters into chemical reagent sulfuric acid absorption tower 14 and continues to absorb, adds ultrapure water by ultrapure water inlet pipe 15 and keeps the concentrated balance of acid, chemical reagent sulfuric acid absorption tower 14 is finished the acid cycle by chemical reagent sulfuric acid recycle pump 16, chemical reagent sulfuric acid water cooler 17, simultaneously by finished product chemical reagent sulfuric acid output pipe 18 output chemical reagent sulfuric acid (analytical pure sulfuric acid); SO now The total absorption rate of gas reaches 99.99%, and remaining almost all is N (surplus is surplus O ) get back to gas mixing device 5, continue gas distribution and finish closed cycle.

[0077] SO in the oleum circulation tank 3 The oleum with free quantity reaching 26% to 32% is pressurized to 100kPa to 150kPa through oleum circulation pump 12, then is sent into SO through evaporator nicotinic acid inlet pipe 13 3 Evaporator 29, at SO 3 In evaporator 29, be heated to 130 ℃ by low-pressure saturated steam and evaporate SO 3 Gas, at SO 3 The SO after evaporation in evaporator 29 3 The normal pressure oleum with free quantity reaching 20% ​​to 23% and temperature being 90 ℃ to 110 ℃ returns to oleum circulation tank and continues to circulate and absorb SO 3 SO in the gaseous mixture 3; SO 3 The SO that evaporator 29 evaporates 3 Gas obtains high-purity SO with purity reaching more than 99.99% after removing the trace amount of sulfuric acid carried over by demister 3 Gas.

[0078] The high-purity SO₃ gas is condensed into liquid SO₃ by SO₃ condenser 28, which is controlled at 35°C. The liquid SO₃ is then stored in liquid SO₃ storage tank 27. Due to the high boiling point of reducing gases such as SO₂, it remains in a gaseous state and returns to gas mixing device 5 through an exhaust pipe. This completes the distillation and purification of SO₃, resulting in an ultrapure SO₃ liquid with a purity of 99.9999%.

[0079] Ultrapure SO3 liquid is vaporized by SO3 vaporizer 26 to obtain ultrapure SO3 gas. The ultrapure SO3 gas is mixed with ultrapure inert gas to obtain electronic-grade sulfuric acid absorption gas, which enters electronic-grade sulfuric acid absorption tower 20 for absorption through ultrapure SO3 gas output pipe 19. Ultrapure water is added through electronic-grade ultrapure water input pipe 21 to maintain the acid concentration balance in the electronic-grade sulfuric acid circulation tank. Electronic-grade sulfuric acid absorption tower 20 completes the circulation absorption through the electronic-grade sulfuric acid circulation tank, equipped with electronic-grade sulfuric acid circulation pump 22 and cluster heat exchanger 23. After the electronic-grade sulfuric acid circulation absorption, the finished electronic-grade sulfuric acid (reaching E1 and E2 grades) is produced through filter 24 and electronic-grade sulfuric acid output pipe 25 and transported in nitrogen-sealed storage tanks. The absorption rate of ultrapure SO3 gas during the electronic-grade sulfuric acid circulation absorption process reaches 99.99%. The remaining gas returns to the mixing device 5 and continues to distribute gas to complete the closed cycle.

[0080] The concentration of the obtained finished electronic-grade sulfuric acid is 92.5% to 98%.

[0081] The above process greatly shortens the purification process of electronic-grade sulfuric acid by purifying the raw gas; at the same time, the gas inside the system can be closed and circulated to achieve "0" emissions, and can be controlled in a closed and clean environment.

[0082] Verification Example 1

[0083] A waste lead battery recycling plant, flue gas volume ~100,000 Nm 3 / h, SO2 concentration 12~120g / Nm 3 , Nitrogen oxides: 400-600 mg / Nm3 The flue gas temperature is ~80℃, the flue gas pressure is ~8.0KPa, and the steps A to F of the process provided by the present invention are combined with the reagent sulfuric acid circulation absorption, and the organic amine desulfurization is combined with the double-tower double-effect + desorption low-boost variable-load deep desorption process. The emission index after organic amine desulfurization is: SO2 concentration 35mg / Nm 3 , sulfuric acid mist 35mg / Nm 3 After further purification, a high-concentration SO2 gas with a SO2 volume concentration of 90% and a water volume concentration of 10% is obtained; after the high-concentration SO2 gas is merged into the air (equivalent to oxygen supplementation), the SO2 concentration in the mixed flue gas reaches 18%, and the total conversion rate reaches 98% through three-stage conversion. The converted flue gas is cooled to 160°C ~ 130°C through heat exchange, and after precise filtration, it enters a refined acid absorption tower (steel lined F4x), and ultrapure water is added to maintain the acid concentration balance. The output sulfuric acid index reaches or exceeds the chemical reagent sulfuric acid analytical purity index.

[0084] Name Index (assay) content (H2SO4), ω / % 96.73 Colour, Hazen units 9 Burning residue (as sulphate), ω / % 0.0006 Chloride (CI), ω / % 0.000025 <![CDATA[硝酸盐(NO3),ω / %]]> ≤0.00005 <![CDATA[氨盐(NH4),ω / %]]> ≤0.0002 Iron (Fe), ω / % ≤0.00002 Copper (Cu), ω / % ≤0.00001 Arsenic (As), ω / % ≤0.000003 Lead (Pb), ω / % ≤0.00001 Reduced potassium permanganate substance (in SO2), ω / % ≤0.00001

[0085] The device provided by the present invention has a simple layout, takes up little space, has high operating efficiency, is easy to manage and operate, achieves the analytical purity index of sulfuric acid as a chemical reagent, and achieves the purpose of saving investment and reducing production costs. This verification example proves the feasibility of the present invention's use of organic amines for absorption and desorption purification of SO2.

[0086] Verification Example 2

[0087] A large nonferrous smelting enterprise, due to the advancement of smelting oxygen enrichment technology, increased metal production by increasing oxygen concentration in the smelting part, and the SO2 concentration in the smelting flue gas reached 19.6%. The technical transformation plan was to add an isothermal pre-conversion method. The flue gas volume entering the isothermal pre-conversion was 60,000Nm 3 / h, SO2 concentration 18%, O2 concentration 14%. The conversion rate of the isothermal pre-conversion stage is ≥90%.

[0088] Although the SO2 concentration in the quasi-isothermal reformer of the present invention is as high as 30%, the oxygen concentration in the flue gas is also as high as 30% by supplementing it with pure oxygen. This results in a higher oxygen-to-sulfur ratio than current smelting devices. Calculations show that the first-stage conversion rate of the quasi-isothermal reformer exceeds 90%, and the overall conversion rate of the present device is ≥ 99.6%. This demonstration, using pure oxygen combined with isothermal pre-conversion, demonstrates the feasibility of producing acid using high-concentration SO2.

[0089] Verification Example 3

[0090] A chemical company producing chlorosulfonic acid and K-acid uses pyrite as raw material. They produce 10,000 tons of liquid SO₃ annually through evaporation and condensation of fuming sulfuric acid. This production is continuous and stable. The SO₃ is purified by distillation to obtain high-purity SO₃. This demonstration demonstrates the feasibility of this SO₃ distillation method.

[0091] Based on the feasibility of the process provided by the present invention verified by the above three verification examples, the present invention illustrates the specific process of the process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption provided by the present invention through the following examples.

[0092] Example

[0093] A process flow chart for producing electronic grade sulfuric acid based on organic amine absorption and desorption is shown in the following figure: Figure 1 As shown, the process steps are as follows:

[0094] A. The SO2-containing flue gas containing impurities and volatile gases with a SO2 volume concentration of 3.2% is cooled by adiabatic evaporation and dust removal in the purification and washing system, and then enters the SO2 flue gas absorption tower 1 for gas-liquid absorption reaction. After the SO2 is removed, the flue gas reaches the ultra-clean emission standard and enters the chimney 36 for discharge. The rich amine liquid that absorbs SO2 in the SO2 flue gas absorption tower 1 is heated by the lean-rich amine heat exchanger 2 and then enters the SO2 desorption tower 3. The rich amine liquid is desorbed in the SO2 desorption tower 3 by secondary steam heating generated by the reboiler, and the product is pure SO2 and water with a temperature of 113°C SO2 saturated gas.

[0095] B. The SO2 saturated gas is first condensed and cooled to 50℃ for dehydration, and then subjected to gas-liquid separation and dehydration to obtain a high-concentration SO2 gas consisting of 92% SO2 and 8% water by volume;

[0096] C. High-concentration SO2 gas, pure O2 and inert gas are mixed to obtain a SO2 water-containing mixed gas at a temperature of 50°C, in which the volume concentration of SO2 reaches 30% and the volume concentration of O2 reaches 29%;

[0097] D. Dry the SO2 gas mixture containing water using concentrated sulfuric acid having a mass fraction of not less than 93% to obtain a SO2 dehydrated gas mixture having a temperature of 50°C and a SO2 volume concentration of 31% in the SO2 dehydrated gas mixture;

[0098] E. The SO2 dehydrated mixed gas can be pressurized to obtain a SO2 pressurized mixed gas with a pressure of 30kPa and a temperature of 80℃. The SO2 pressurized mixed gas is subjected to a first-stage heating to obtain a SO2 first-stage heating mixed gas with a pressure of 28.5kPa and a temperature of 300℃. After a second-stage heating, a SO2 second-stage heating mixed gas with a pressure of 27.2kPa and a temperature of 350℃ is obtained. After a third-stage heating, a SO2 converted mixed gas with a pressure of 26kPa and a temperature of 400℃ is obtained. The SO2 converted mixed gas is subjected to a first-stage conversion to output a first-stage converted mixed gas with a pressure of 24kPa and a temperature of 500℃. The first-stage converted mixed gas is subjected to a first-stage cooling to output a pressure of 23kPa and a temperature of 26kPa. The first-stage cooling mixed gas is 440°C; the first-stage cooling mixed gas outputs a second-stage conversion mixed gas with a pressure of 20.8kPa and a temperature of 490°C after the second-stage conversion; the second-stage conversion mixed gas outputs a second-stage cooling mixed gas with a pressure of 19kPa and a temperature of 420°C after the second-stage cooling; the second-stage cooling mixed gas outputs a third-stage conversion mixed gas with a pressure of 17kPa and a temperature of 445°C after the third-stage conversion; the third-stage conversion mixed gas outputs a SO3 mixed gas with a pressure of 15kPa and a temperature of 215°C after the third-stage cooling. The composition of the SO3 mixed gas is SO3, excess O2, inert gas and a small amount of impurities; the total SO2 conversion rate after multi-stage conversion can reach 99.5%;

[0099] F, the SO3 gas mixture with a pressure of 15kPa and a temperature of 215 ℃ is fed from the bottom of the oleum absorption tower 10 and is met with the oleum with a pressure of 120kPa and a temperature of 52 ℃ from top to bottom and is absorbed part SO3, and the oleum with a temperature of 65 ℃ is returned to the oleum circulation tank and is pressurized by the oleum circulation pump 12 and cooled by the oleum cooler 11 to be the oleum with a pressure of 120kPa and a temperature of 52 ℃ and continues to participate in the circulation absorption; The SO3 in the SO3 gas mixture is absorbed 37% by the oleum circulation and contains the remaining part SO3 with a pressure of 15kPa and a temperature of 80 ℃ is transported to the chemical reagent sulfuric acid absorption tower 14 for circulation absorption; The SO3 gas mixture with a pressure of 12kPa and a temperature of 80 ℃ is fed from the bottom of the chemical reagent sulfuric acid absorption tower 14 and is met with the chemical reagent sulfuric acid with a pressure of 120kPa and a temperature of 70 ℃ from top to bottom and is absorbed part SO3, and the generation temperature is 9 The atmospheric chemical reagent sulfuric acid at 0°C is returned to the chemical reagent sulfuric acid circulation tank and is pressurized by the chemical reagent sulfuric acid circulation pump 16 and cooled by the chemical reagent sulfuric acid cooler 17 to a pressure of 120kPa and a temperature of 70°C, and the chemical reagent sulfuric acid continues to participate in the circulation absorption, and the tail gas composed of surplus O and inert gas at a pressure of 9kPa and a temperature of 75°C outputted from the top of the chemical reagent sulfuric acid absorption tower 14 is returned to step C and continues to participate in the circulation; the chemical reagent sulfuric acid circulation tank is supplemented with ultrapure water through the ultrapure water inlet pipe 15 to maintain acid concentration balance, the chemical reagent sulfuric acid at a temperature of 90°C in the chemical reagent sulfuric acid circulation tank is pressurized by the chemical reagent sulfuric acid circulation pump 16 and cooled by the chemical reagent sulfuric acid cooler 17 to a pressure of 120kPa and a temperature of 70°C, and is output through the finished chemical reagent sulfuric acid output pipe 18; the total SO absorption rate of the SO in the SO mixed gas after the oleum circulation absorption and the chemical reagent sulfuric acid circulation absorption can reach 99.99%;

[0100] The SO in G, the oleum circulation groove Free quantity reaches 30% oleum and is pressurized to 120kPa through oleum circulation pump 12, then sends into SO by evaporator nicotinic acid inlet pipe 13 Evaporator 29, the SO of low-pressure steam heating Evaporator 29 pairs of SO Free quantity reaches 30% oleum evaporation impurity removal and acquisition pressure and is that 40kPa, temperature are 130 ℃ SO Gas, SO Free quantity reaches 30% oleum through SO After the evaporation, it is reduced to SO Free quantity reaches 22% and temperature is that 100 ℃ normal pressure oleum returns to the oleum circulation groove; SO The evaporation process of evaporator 29 can remove trace heavy metals and dust that carry privately, SO The SO that evaporator 29 evaporates out Gas obtains the high-purity SO of purity reaching more than 99.99% after removing the trace sulfuric acid that carries privately through demister Gas;

[0101] H. The high-purity SO3 gas enters the SO3 condenser 28 at a temperature of 35°C for liquefied rectification (rectification to remove other non-condensable gases based on their different characteristics), and the super-pure SO3 liquid with a pressure of 0.3 kPa and a temperature of 35°C and a purity of more than 99.9999% is obtained and sent to the liquid SO3 storage tank 27 for storage; the gaseous reducing gas (such as SO2 gas) generated by the liquefied rectification is returned to the gas mixing device 5 in step C through the valve-equipped pipeline provided on the SO3 condenser 28 or the liquid SO3 storage tank 27;

[0102] I. The super-pure SO3 liquid is sent to the SO3 vaporizer 26 at a vaporization temperature of 65°C, and the SO3 vaporizer 26 heated by low-pressure steam outputs super-pure SO3 gas at a pressure of 10 kPa and a temperature of 65°C, which is mixed with super-pure inert gas to obtain electronic-grade sulfuric acid absorption gas and is input into the electronic-grade sulfuric acid absorption tower 20; the residual liquid generated by the SO3 vaporizer 26 is transported to the fuming sulfuric acid circulating tank to participate in SO3 absorption;

[0103] J. The electronic-grade sulfuric acid absorption gas from the bottom of the electronic-grade sulfuric acid absorption tower 20 is absorbed by meeting the electronic-grade sulfuric acid from top to bottom at a pressure of 10 kPa and a temperature of 65°C, generating normal-pressure electronic-grade sulfuric acid at a temperature of 85°C, which is returned to the electronic-grade sulfuric acid circulating tank and pressurized by the electronic-grade sulfuric acid circulating pump 22 and cooled by the cluster heat exchanger 23 to electronic-grade sulfuric acid at a pressure of 120 kPa and a temperature of 65°C for further participation in the circulating absorption, and the inert gas at a pressure of 7.5 kPa and a temperature of 70°C output from the top of the electronic-grade sulfuric acid absorption tower 20 is returned to step C for further participation in the circulation, so that the tail gas is discharged; the electronic-grade sulfuric acid circulating tank is supplemented with electronic-grade ultra-pure water through the electronic-grade ultra-pure water input pipe 21 to maintain the acid concentration balance, the purity of the electronic-grade ultra-pure water is 99.9999 wt%, and the absorption rate of the super-pure SO3 gas in the electronic-grade sulfuric acid absorption gas can reach 99.99%;

[0104] K. After the electronic-grade sulfuric acid is pressurized by the electronic-grade sulfuric acid circulating pump 22 and cooled by the cluster heat exchanger 23 to a pressure of not higher than 100 kPa and a temperature of not higher than 40°C, it is sent to the filter 24 with a filter membrane pore size of 0.1 μm to 1 μm for three-stage filtration to obtain the finished electronic-grade sulfuric acid, which is output through the electronic-grade sulfuric acid output pipe 25 to the electronic-grade sulfuric acid storage tank for nitrogen-sealed preservation, and the finished electronic-grade sulfuric acid meets the E1 grade in the national standard GB / T41881-2022.

[0105] The process of the present application can obtain SO3 gas with purity of 99.9999% by distillation purification of SO3 gas evaporated from clean oleum, which is several orders of magnitude higher than that of SO3 gas evaporated from industrial-grade oleum. The high-purity SO3 gas is absorbed in an electronic-grade sulfuric acid absorption tower 20 (lined with ultra-pure PTFE and filled with ultra-pure PFA Pall rings) in a clean environment to produce electronic-grade sulfuric acid (E1 and E2 grades) in an electronic-grade sulfuric acid absorption tower 20 (lined with ultra-pure PTFE and filled with ultra-pure PFA Pall rings). The process greatly shortens the time to reach the standard and overcomes the problems of long time to reach the standard and unstable product of other processes. Therefore, it is suitable for popularization and use.

[0106] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the above embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present application. The technologies not involved in the present application can be realized by the prior art.

Claims

1. A process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption, characterized in that: The process steps are as follows: A. SO2 flue gas containing other components is treated by organic amine absorption and desorption process to obtain SO2 saturated gas with pure SO2 and water as the products; B. SO2 saturated gas is condensed and separated into gas and liquid to obtain high-concentration SO2 gas with a SO2 volume concentration of 80% to 95%; C. High-concentration SO2 gas, pure O2 and inert gas are mixed to obtain a SO2 water-containing mixed gas with a SO2 volume concentration of 7% to 40%; D. Use concentrated sulfuric acid with a mass fraction of not less than 93% to dry the SO2 water-containing mixed gas to obtain the SO2 dehydrated mixed gas; E. The SO2 dehydrated mixed gas is pressurized and heated, and then subjected to multi-stage conversion to obtain a SO3 mixed gas composed of SO3, excess O2, inert gas and a small amount of impurities; F. SO3 mixed gas is absorbed by fuming sulfuric acid in a cycle; G. Oleum sulfuric acid with a free SO3 content of 26% to 32% is sent to the SO3 evaporator for evaporation and impurity removal to obtain high-purity SO3 gas with a purity of more than 99.99%; H. High-purity SO3 gas is liquefied and distilled to obtain ultra-pure SO3 liquid with a purity of more than 99.9999%; I. Ultrapure SO3 liquid is vaporized into ultrapure SO3 gas and then mixed with ultrapure inert gas to obtain electronic grade sulfuric acid absorption gas; J. Electronic grade sulfuric acid absorption The gas is absorbed by electronic grade sulfuric acid in a cycle; K. The electronic grade sulfuric acid obtained by the cyclic absorption is filtered through the filter and then output as finished electronic grade sulfuric acid that meets the national standard GB / T41881-2022.

2. The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption according to claim 1, characterized in that: The SO3 in the SO3 mixed gas in step F is cyclically absorbed by fuming sulfuric acid by 35% to 50%, and the SO3 mixed gas carrying the remaining SO3 is cyclically absorbed by chemical reagent sulfuric acid. The finished chemical reagent sulfuric acid obtained after the cyclic absorption of the chemical reagent sulfuric acid is cooled and output, and the tail gas composed of surplus O2 and inert gas returns to step C to continue participating in the cycle; ultrapure water is supplemented during the cyclic absorption of the chemical reagent sulfuric acid.

3. The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption according to claim 2, characterized in that: The finished chemical reagent sulfuric acid obtained after the cyclic absorption of the chemical reagent sulfuric acid is transported to step D to participate in the drying of the SO2 mixed gas and / or transported to step F to participate in the cyclic absorption of fuming sulfuric acid.

4. The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption according to any one of claims 1 to 3, characterized in that: The SO2-containing flue gas in step A is a flue gas containing impurities and volatile gases with a SO2 volume concentration of 0.1% to 7%. The SO2-containing flue gas is subjected to adiabatic evaporation cooling and dust removal in the purification and washing system, and then enters the SO2 flue gas absorption tower to undergo gas-liquid absorption reaction with an organic amine liquid. After the SO2 is removed, the flue gas reaches the ultra-clean emission standard and enters the chimney for discharge. The rich amine liquid that has absorbed SO2 in the SO2 flue gas absorption tower is heated by a lean-rich amine heat exchanger and then enters the SO2 desorption tower. The rich amine liquid is desorbed in the SO2 desorption tower by heating with secondary steam generated by a reboiler to obtain SO2 saturated gas with a temperature of 90°C to 125°C.

5. The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption according to any one of claims 1 to 3, characterized in that: The SO2 saturated gas in step B is first condensed and cooled to 40°C to 80°C for dehydration, and then subjected to gas-liquid separation and dehydration to obtain a high-concentration SO2 gas consisting of 80% to 95% SO2 and 20% to 5% water by volume; the high-concentration SO2 gas, pure O2 and inert gas in step C are mixed to obtain a SO2 water-containing mixed gas with a temperature of 50°C to 90°C, and the volume concentration of O2 in the SO2 water-containing mixed gas reaches 7% to 40%.

6. The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption according to any one of claims 1 to 3, characterized in that: The supplementary source of concentrated sulfuric acid with a mass fraction of not less than 93% in step D is fuming sulfuric acid in step F or chemical reagent sulfuric acid. The output temperature of the SO2 dehydrated mixed gas in step D is 50°C to 120°C; the volume concentration of SO2 in the SO2 dehydrated mixed gas in step D is 12% to 40%.

7. The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption according to any one of claims 1 to 3, characterized in that: The pressurization in the step E can obtain a SO2 pressurized mixed gas with a pressure of 25kPa to 40kPa and a temperature of 70°C to 170°C. After multi-stage heating, the SO2 pressurized mixed gas obtains a SO2 conversion mixed gas with a pressure of 22kPa to 37kPa and a temperature of 380°C to 450°C. After multi-stage conversion, the SO2 conversion mixed gas obtains a SO3 mixture with a pressure of 12kPa to 27kPa and a temperature of 160°C to 220°C. The total SO2 conversion rate after multi-stage conversion can reach 99.5%.

8. The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption according to claim 7, characterized in that: The SO2 pressurized mixed gas is subjected to a first-stage heating to obtain a SO2 first-stage heating mixed gas with a pressure of 24kPa~39kPa and a temperature of 200℃~300℃, and a second-stage heating to obtain a SO2 second-stage heating mixed gas with a pressure of 26kPa~38kPa and a temperature of 250℃~350℃, and a third-stage heating to obtain a SO2 conversion mixed gas with a pressure of 22kPa~37kPa and a temperature of 380℃~450℃; the SO2 conversion mixed gas is subjected to a first-stage conversion to output a first-stage conversion mixed gas with a pressure of 19kPa~34kPa and a temperature of 500℃~600℃, and the first-stage conversion mixed gas is subjected to a first-stage cooling to output a pressure of 18kPa~3 The first-stage cooling mixed gas has a pressure of 3kPa and a temperature of 410℃~460℃; the first-stage cooling mixed gas outputs a second-stage conversion mixed gas with a pressure of 16kPa~31kPa and a temperature of 450℃~550℃ after the second-stage conversion, and the second-stage conversion mixed gas outputs a second-stage cooling mixed gas with a pressure of 15kPa~30kPa and a temperature of 410℃~430℃ after the second-stage cooling; the second-stage cooling mixed gas outputs a third-stage conversion mixed gas with a pressure of 13kPa~28kPa and a temperature of 440℃~460℃ after the third-stage conversion, and the third-stage conversion mixed gas outputs a SO3 mixed gas with a pressure of 12kPa~27kPa and a temperature of 160℃~220℃ after the third-stage cooling.

9. The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption according to claim 8, characterized in that: The conversion rate of the primary conversion is 60% to 90%; the sum of the conversion rates of the primary conversion and the secondary conversion is 90% to 97%; the sum of the conversion rates of the primary conversion, the secondary conversion and the tertiary conversion can reach 99.5%.

10. The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption according to any one of claims 1 to 3, characterized in that: The process of adopting oleum for cyclic absorption of the SO3 gas mixture in the step F is as follows: the SO3 gas mixture at a pressure of 12kPa-27kPa and a temperature of 160°C-220°C is fed from the bottom of the oleum absorption tower and meets the oleum at a pressure of 100kPa-150kPa and a temperature of 50°C-60°C from top to bottom to be absorbed by the absorbed portion of SO3, the generated oleum at a temperature of 60°C-80°C is returned to the oleum circulation tank and is pressurized by the oleum circulation pump and cooled by the oleum cooler to a oleum at a pressure of 100kPa-150kPa and a temperature of 50°C-60°C, and continues to participate in the cyclic absorption, and the SO3 gas mixture containing the remaining portion of SO3 at a pressure of 9kPa-24kPa and a temperature of 80°C-130°C is transported to the chemical reagent sulfuric acid absorption tower for cyclic absorption.

11. The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption according to claim 10, characterized in that: The chemical reagent sulfuric acid absorption tower has the following cyclic absorption process: the SO3 mixed gas with a pressure of 9kPa to 24kPa and a temperature of 80℃ to 130℃ is introduced from the bottom of the chemical reagent sulfuric acid absorption tower and meets the chemical reagent sulfuric acid with a pressure of 100kPa to 150kPa and a temperature of 60℃ to 80℃ from top to bottom, and the remaining SO3 is absorbed to generate the atmospheric pressure chemical reagent sulfuric acid with a temperature of 70℃ to 100℃, which is returned to the chemical reagent sulfuric acid circulation tank and pressurized by the chemical reagent sulfuric acid circulation pump and cooled by the chemical reagent sulfuric acid cooler to the pressure of 100kPa to 150kPa and the temperature of 60℃ to 80℃. The acid continues to participate in the circulation absorption, and the tail gas composed of surplus O2 and inert gas with a pressure of 6kPa to 21kPa and a temperature of 70°C to 90°C outputted from the top of the chemical reagent sulfuric acid absorption tower returns to step C and continues to participate in the circulation; the chemical reagent sulfuric acid circulation tank is supplemented with ultrapure water through the ultrapure water inlet pipe to maintain the acid concentration balance, the chemical reagent sulfuric acid with a temperature of 70°C to 90°C in the chemical reagent sulfuric acid circulation tank is pressurized by the chemical reagent sulfuric acid circulation pump and cooled by the chemical reagent sulfuric acid cooler to a pressure of 100kPa to 150kPa and a temperature of 60°C to 80°C, and is output through the finished chemical reagent sulfuric acid output pipe.

12. The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption according to any one of claims 1 to 3, characterized in that: The evaporation temperature of the SO3 evaporator in the step G is 90°C to 130°C. The oleum from the oleum circulation tank with a free SO3 content of 26% to 32% is pressurized to 100kPa to 150kPa by the oleum circulation pump and then input into the SO3 evaporator heated by low-pressure steam. After evaporation and impurity removal, high-purity SO3 gas with a pressure of 20kPa to 50kPa and a temperature of 90°C to 140°C is obtained. The oleum from the oleum circulation tank is evaporated to obtain normal-pressure oleum with a temperature of 90°C to 110°C and a free SO3 content of 20% to 23%, which is returned to the oleum circulation tank.

13. The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption according to any one of claims 1 to 3, characterized in that: The high-purity SO3 gas in step H enters a SO3 condenser at a temperature of 30°C to 50°C for liquefaction and distillation, and an ultra-pure SO3 liquid with a pressure of 0kPa to 1kPa, a temperature of 20°C to 35°C and a purity of more than 99.9999% is obtained, which is sent to a liquid SO3 storage tank for storage; the gaseous reducing gas generated by the liquefaction and distillation is returned to the gas mixing device in step C through a pipeline with a valve provided on the SO3 condenser or the liquid SO3 storage tank.

14. The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption according to any one of claims 1 to 3, characterized in that: The ultrapure SO3 liquid in step I is fed into a SO3 vaporizer with a vaporization temperature of 50°C to 80°C. The SO3 vaporizer heated by low-pressure steam outputs ultrapure SO3 gas with a pressure of 10kPa to 15kPa and a temperature of 60°C to 80°C. The electronic-grade sulfuric acid absorption gas obtained by mixing the ultrapure SO3 gas with an ultrapure inert gas is fed into an electronic-grade sulfuric acid absorption tower; the residual liquid generated by the SO3 vaporizer is transported to a fuming sulfuric acid circulation tank to participate in SO3 absorption.

15. The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption according to any one of claims 1 to 3, characterized in that: The process of the electronic-grade sulfuric acid circulation absorption in step J is as follows: the electronic-grade sulfuric acid absorption gas is introduced from the bottom of the electronic-grade sulfuric acid absorption tower into the electronic-grade sulfuric acid at a pressure of 10kPa-15kPa and a temperature of 60°C-80°C from top to bottom and is absorbed, generating normal-pressure electronic-grade sulfuric acid at a temperature of 70°C-100°C, which is returned to the electronic-grade sulfuric acid circulation tank and pressurized by the electronic-grade sulfuric acid circulation pump and cooled by the cluster heat exchanger to electronic-grade sulfuric acid at a pressure of 10kPa-15kPa and a temperature of 60°C-80°C to continue to participate in the circulation absorption, and the inert gas at a pressure of 6kPa-11kPa and a temperature of 70°C-90°C output from the top of the electronic-grade sulfuric acid absorption tower is returned to step C to continue to participate in the circulation; the electronic-grade sulfuric acid circulation tank is supplemented with electronic-grade ultrapure water through the electronic-grade ultrapure water inlet pipe to maintain acid concentration balance.

16. The process for producing electronic-grade sulfuric acid based on organic amine absorption and desorption according to any one of claims 1 to 3, characterized in that: The electronic-grade sulfuric acid in step K is pressurized by an electronic-grade sulfuric acid circulation pump and cooled by a cluster heat exchanger to a pressure not higher than 100 kPa and a temperature not higher than 40° C., and then sent to a filter with a membrane pore size of 0.1 μm to 1 μm for 1 to 3 stages of filtration to obtain finished electronic-grade sulfuric acid. The finished electronic-grade sulfuric acid is output through an electronic-grade sulfuric acid output pipe to an electronic-grade sulfuric acid storage tank for nitrogen-sealed storage.

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