CN111115587A - Method and system for preparing analytically pure sulfuric acid from smelting flue gas - Google Patents
Method and system for preparing analytically pure sulfuric acid from smelting flue gas Download PDFInfo
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- CN111115587A CN111115587A CN202010062119.7A CN202010062119A CN111115587A CN 111115587 A CN111115587 A CN 111115587A CN 202010062119 A CN202010062119 A CN 202010062119A CN 111115587 A CN111115587 A CN 111115587A
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- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 title claims abstract description 203
- 239000003546 flue gas Substances 0.000 title claims abstract description 89
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 85
- 238000000034 method Methods 0.000 title claims abstract description 58
- 238000003723 Smelting Methods 0.000 title claims abstract description 45
- 239000002253 acid Substances 0.000 claims abstract description 253
- 239000007789 gas Substances 0.000 claims abstract description 185
- RAHZWNYVWXNFOC-UHFFFAOYSA-N sulfur dioxide Inorganic materials O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 claims abstract description 161
- 238000010521 absorption reaction Methods 0.000 claims abstract description 160
- 238000006243 chemical reaction Methods 0.000 claims abstract description 58
- 238000001035 drying Methods 0.000 claims abstract description 53
- 238000005406 washing Methods 0.000 claims abstract description 40
- 238000001816 cooling Methods 0.000 claims abstract description 36
- 238000003795 desorption Methods 0.000 claims abstract description 32
- 238000007872 degassing Methods 0.000 claims abstract description 28
- 239000003595 mist Substances 0.000 claims abstract description 28
- 239000002912 waste gas Substances 0.000 claims abstract description 20
- 230000003647 oxidation Effects 0.000 claims abstract description 11
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 11
- 239000007788 liquid Substances 0.000 claims description 90
- 238000009826 distribution Methods 0.000 claims description 26
- 239000012535 impurity Substances 0.000 claims description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 20
- 238000004519 manufacturing process Methods 0.000 claims description 11
- 150000001412 amines Chemical class 0.000 claims description 9
- 238000001914 filtration Methods 0.000 claims description 9
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- 238000002360 preparation method Methods 0.000 abstract description 24
- TXKMVPPZCYKFAC-UHFFFAOYSA-N disulfur monoxide Inorganic materials O=S=S TXKMVPPZCYKFAC-UHFFFAOYSA-N 0.000 description 65
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical compound S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 65
- AKEJUJNQAAGONA-UHFFFAOYSA-N sulfur trioxide Inorganic materials O=S(=O)=O AKEJUJNQAAGONA-UHFFFAOYSA-N 0.000 description 21
- 229910052717 sulfur Inorganic materials 0.000 description 16
- 239000011593 sulfur Substances 0.000 description 16
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 14
- 230000008569 process Effects 0.000 description 13
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- 229910052801 chlorine Inorganic materials 0.000 description 6
- 239000011737 fluorine Substances 0.000 description 6
- 229910052731 fluorine Inorganic materials 0.000 description 6
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 6
- 230000001590 oxidative effect Effects 0.000 description 6
- 239000000779 smoke Substances 0.000 description 6
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 5
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 5
- PVNIIMVLHYAWGP-UHFFFAOYSA-N Niacin Chemical compound OC(=O)C1=CC=CN=C1 PVNIIMVLHYAWGP-UHFFFAOYSA-N 0.000 description 5
- -1 amine salts Chemical class 0.000 description 5
- 230000008901 benefit Effects 0.000 description 5
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- 239000000463 material Substances 0.000 description 5
- 229910021645 metal ion Inorganic materials 0.000 description 5
- 239000012498 ultrapure water Substances 0.000 description 5
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 4
- 239000000498 cooling water Substances 0.000 description 4
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- 229910002651 NO3 Inorganic materials 0.000 description 3
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- 239000011664 nicotinic acid Substances 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
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- 238000010438 heat treatment Methods 0.000 description 2
- 229960003512 nicotinic acid Drugs 0.000 description 2
- 235000001968 nicotinic acid Nutrition 0.000 description 2
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- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
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- 150000002823 nitrates Chemical class 0.000 description 1
- YPJKMVATUPSWOH-UHFFFAOYSA-N nitrooxidanyl Chemical compound [O][N+]([O-])=O YPJKMVATUPSWOH-UHFFFAOYSA-N 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 239000012286 potassium permanganate Substances 0.000 description 1
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Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/69—Sulfur trioxide; Sulfuric acid
- C01B17/74—Preparation
- C01B17/76—Preparation by contact processes
- C01B17/80—Apparatus
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/48—Sulfur dioxide; Sulfurous acid
- C01B17/50—Preparation of sulfur dioxide
- C01B17/56—Separation; Purification
Abstract
The invention discloses a method and a system for preparing analytically pure sulfuric acid from smelting flue gas, wherein the method comprises the step of containing SO2The smelting flue gas is purified, cooled, acid mist reduced and ultrapure SO2Preparing gas, preparing acid-making gas, drying and converting, preparing absorption acid and carrying out oxidation stripping. The system comprises a washing cooling tower, an electric demister, a sulfur dioxide absorption tower, a sulfur dioxide desorption tower, a gas preparation tank, a drying tower, a conversion system, an acid preparation absorption tower and a degassing tower which are sequentially communicated, wherein a lean rich solution heat exchanger is arranged between the sulfur dioxide absorption tower and the sulfur dioxide desorption tower, and an acid preparation tail gas outlet and a stripping waste gas outlet are respectively communicated with a gas inlet arranged on the electric demister. The method and system of the present invention can achieve almost 100% SO2The gas is recycled to prepare sulfuric acid, the yield of analytically pure sulfuric acid reaches 100%, the finished acid completely reaches the standard of analytically pure sulfuric acid, and the method is suitable for various flue gas conditions.
Description
Technical Field
The invention relates to a preparation technology of analytically pure sulfuric acid, in particular to a method and a system for preparing analytically pure sulfuric acid from smelting flue gas.
Background
Analytically pure sulfuric acid is widely applied to industries such as industrial analysis, chemical experiments, medicines, storage batteries, electronics and the like. The traditional rectification process adopts a method of firstly oxidizing industrial sulfuric acid, then carrying out reduced pressure rectification and finally carrying out microfiltration on the distillate to prepare analytically pure sulfuric acid. The process has high requirements on equipment, high energy consumption and high cost, is only suitable for small-scale production, cannot meet the requirements of large-scale use, energy conservation and consumption reduction of the current analytically pure sulfuric acid, and is imperative in development of a new analytically pure sulfuric acid preparation process.
In the prior art, some methods firstly adopt converted flue gas to prepare nicotinic acid, and then utilize heat sources such as steam and the like to partially dissociate SO of fuming sulfuric acid3Evaporated and absorbed by ultrapure water to prepare analytically pure sulfuric acid. The method can only distill off part of SO in the nicotinic acid3Therefore, the yield of the analytically pure sulfuric acid is low, and meanwhile, an acid evaporator has the defect of small single processing capacity, a plurality of acid evaporators need to be arranged to run simultaneously during mass production, so that the investment cost, the operation difficulty and the occupied area are increased, in addition, impurities in the nicotinic acid can be separated out in the acid evaporation process, equipment and pipelines are scaled, the regular cleaning is needed, otherwise, the acid evaporation efficiency is influenced, and the energy consumption of the acid evaporation is increased. There are also some methods to clean the flue gas by washing, filtering and other means, and then to remove SO from the flue gas2Conversion to SO3Then directly absorbing SO by adopting ultrapure water3Analytically pure sulfuric acid was prepared. There are several drawbacks to this type of process: (1) the nitrogen oxides in the smelting flue gas cannot be removed by means of cleaning, filtering and other cleaning means, and the content of nitrate radical impurities in the prepared sulfuric acid directly absorbed after the flue gas is cleaned and converted cannot reach the index of analytically pure sulfuric acid; (2) before the flue gas is converted, concentrated sulfuric acid is used for drying to remove water, but impurities in the flue gas cannot be completely removed by flue gas washing, filtering and other purification, the impurities are introduced in the concentrated sulfuric acid drying, and the dried acid can only be used for preparing industrial sulfuric acid and cannot produce analytically pure sulfuric acid meeting the standard; (3) SO in flue gas2Catalytic conversion to SO3Requires SO2The concentration is kept in a certain range and is continuously stable, SO2The smelting flue gas with too low concentration, too high concentration or large fluctuation can not be used by the method.
In the preparation method of analytically pure sulfuric acid, both indirect method and direct method have a common problem that the analytically pure sulfuric acid can not be prepared 100%, and the by-product industrial sulfuric acid is accompanied, so that the economic benefit of sulfur resource recovery can not be maximized.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a sulfur-containing flue gas recycling system which is suitable for various flue gas conditions, can maximize the utilization of sulfur-containing flue gas resources and enables SO (sulfur oxide) to be generated2The method and the system for preparing the analytically pure sulfuric acid from the smelting flue gas have the gas recovery utilization rate almost reaching 100 percent and the finished acid completely reaching the standard of the analytically pure sulfuric acid.
In order to solve the technical problems, the invention adopts the following technical scheme.
A method for preparing analytically pure sulfuric acid by smelting flue gas comprises the following steps:
s1: will contain SO2The smelting flue gas is washed and cooled to capture and remove impurities in the flue gas and is cooled to below 40 ℃ to obtain cooling impurity-removed gas;
s2: cooling the impurity-removed gas, and reducing acid mist until the acid mist is reduced to 5mg/m3Obtaining acid mist reducing gas;
s3: organic amine liquid is used as absorption liquid, and absorption liquid barren solution is adopted to reduce SO in acid mist gas2Adsorbing to remove SO in the gas2The concentration is reduced to 50mg/m3Obtaining rich absorption liquid and tail gas, discharging the tail gas, desorbing the rich absorption liquid to obtain ultrapure SO2Gas and absorption liquid barren solution, and SO in the flue gas after the absorption of the absorption liquid barren solution circulation and acid mist reduction2；
S4: mixing ultrapure SO2Mixing the gas with air to prepare acid-making gas, and preparing SO in the acid-making gas2The mass fraction of (A) is kept between 4 and 6 percent;
S5：drying and absorbing water of acid making gas by adopting analytically pure sulfuric acid with the mass fraction of 93-95 percent to reduce the water content of the acid making gas to 0.1mg/m3Obtaining a dry acid-making gas and a dry acid;
s6: converting the dried acid-making gas under the action of a catalyst to make SO2Conversion to SO3To obtain converted gas, and then filtering;
s7: absorbing the filtered converted gas by adopting analytically pure sulfuric acid with the mass fraction of 95-98% to absorb SO in the converted gas3And adjusting the mass fraction of the absorbed acid to 95% -98%, carrying out oxidation stripping to obtain finished analytically pure sulfuric acid and stripping waste gas, and returning the acid making tail gas and the stripping waste gas to the step S2 for acid mist reduction treatment.
In the method for preparing analytically pure sulfuric acid from smelting flue gas, preferably, in step S5, the temperature of the obtained dry acid is reduced to 40 ℃ to 60 ℃, the mass fraction of the dry acid is adjusted to 93% to 95%, part of the adjusted dry acid is recycled for drying and water absorption, and the other part of the adjusted dry acid is sent to step S7 to adjust the concentration of the absorption acid together with the make-up water.
Preferably, in the step S7, the temperature of the obtained absorption acid is reduced to 60-80 ℃, and the adjusted absorption acid is partially recycled for SO3The part of the solution is sent to step S5 to adjust the concentration of the dry acid, and the remaining part is subjected to degassing treatment.
In the method for preparing analytically pure sulfuric acid from smelting flue gas, preferably, in the step S1, the washing and cooling are performed in two steps: firstly washing by dynamic wave until the temperature drops to 60-70 ℃, then washing and cooling until the temperature drops to below 40 ℃, and capturing and removing the impurities by two times of washing.
In the method for preparing analytically pure sulfuric acid from smelting flue gas, preferably, in the step S6, the conversion is a primary conversion, and the SO is2Conversion to SO3The conversion rate of (a) is more than 95%; and/or the temperature of the dry acid making gas is firstly raised to 420-450 DEG CThen the conversion is carried out, and the temperature of the obtained conversion gas is reduced to 80-180 ℃ and then filtered.
In the method for preparing analytically pure sulfuric acid from smelting flue gas, preferably, in the step S7, the oxidizing stripping includes absorbing SO in acid with an oxidizing agent2Carrying out oxidation and using air to treat unoxidized SO2And (4) carrying out stripping.
In the method for preparing analytically pure sulfuric acid from smelting flue gas, preferably, in step S4 and step S7, the air is filtered clean air.
As a general technical concept, the invention further provides a system for preparing analytically pure sulfuric acid from smelting flue gas, which comprises a washing cooling tower, an electric demister, a sulfur dioxide absorption tower, a sulfur dioxide desorption tower, a gas preparation tank, a drying tower, a conversion system, an acid preparation absorption tower and a degassing tower which are sequentially communicated, wherein a barren and rich liquid heat exchanger for sending absorption liquid rich liquid generated by the sulfur dioxide absorption tower to the sulfur dioxide desorption tower and sending absorption liquid barren liquid generated by the sulfur dioxide desorption tower to the sulfur dioxide absorption tower and carrying out barren and rich liquid heat exchange is arranged between the sulfur dioxide absorption tower and the sulfur dioxide desorption tower, the acid preparation absorption tower is provided with an acid preparation tail gas outlet, the degassing tower is provided with a stripping waste gas outlet, and the acid preparation tail gas outlet and the stripping waste gas outlet are respectively communicated with a gas inlet arranged on the electric demister.
In the above system for preparing analytically pure sulfuric acid from smelting flue gas, preferably, the drying tower is provided with a dry acid outlet, a dry acid inlet and an absorption acid reflux port, the acid making absorption tower is provided with an absorption acid outlet, an absorption acid inlet and a dry acid reflux port, the degassing tower is provided with a degassing tower inlet, the dry acid outlet is communicated with a third pipeline, the third pipeline is provided with a dry acid cooler, the third pipeline is provided with a first branch and a second branch, the first branch is communicated with the dry acid inlet, the second branch is communicated with the dry acid reflux port, the absorption acid outlet is communicated with a fourth pipeline, the fourth pipeline is provided with an acid making cooler, the fourth pipeline is provided with a third branch, a fourth branch and a fifth branch, the third branch is communicated with the absorption acid inlet, and the fourth branch is communicated with the degassing tower inlet, the fifth branch is communicated with the absorption acid return opening.
Preferably, the washing cooling tower is provided with a liquid outlet and a liquid inlet, the liquid outlet and the liquid inlet of the washing cooling tower are communicated through a first pipeline, and the first pipeline is provided with a washing acid cooler.
Preferably, the sulfur dioxide desorption tower is provided with a rich liquid heat exchange outlet and a rich liquid heat exchange inlet, the rich liquid heat exchange outlet is communicated with the rich liquid heat exchange inlet through a second pipeline, and the second pipeline is provided with a reboiler.
In the system for preparing analytically pure sulfuric acid from smelting flue gas, preferably, the gas distribution tank is provided with a gas distribution inlet, and the gas distribution inlet is communicated with a gas distribution filter.
In the system for preparing analytically pure sulfuric acid from smelting flue gas, preferably, the degassing tower is provided with an air inlet, and the air inlet is communicated with an air filter.
Preferably, the system for preparing analytically pure sulfuric acid from smelting flue gas further comprises a dynamic wave scrubber, and the dynamic wave scrubber is communicated with an air inlet formed in the scrubbing cooling tower.
Preferably, the system for preparing analytically pure sulfuric acid from smelting flue gas further comprises SO3A precision filter, wherein SO is passed between the conversion system and the acid making absorption tower3The precision filter is communicated.
Preferably, the conversion system comprises a converter and a heat exchange assembly which are communicated with each other, and the converter is a three-stage converter.
Compared with the prior art, the invention has the advantages that:
1. the method adopts organic amine liquid to treat the flue gas SO2Preparation of ultrapure SO by absorption and desorption2Gas then convectionPure SO2Gas distribution, drying, conversion, filtration, absorption, and finally blowing off, oxidizing and removing impurities to obtain SO2Conversion of the gas to analytically pure sulfuric acid, and SO2The utilization of (c) is almost 100%.
The invention maximizes the utilization of sulfur-containing flue gas resources and mainly relates to two aspects: (1) by blowing off SO in acid making tail gas and stripping waste gas2The sulfur resource in the flue gas is almost 100 percent prepared into sulfuric acid by secondary absorption, and the defects that the sulfur resource in the acid making tail gas cannot be recovered by other technologies and a tail gas treatment device needs to be additionally arranged do not exist; (2) the yield of the analytically pure sulfuric acid is 100 percent, the yield of other technologies is only about 50 percent or even lower, the unit price of the analytically pure sulfuric acid is far higher than that of industrial sulfuric acid, and sulfur resources with the same quality can generate higher economic value by adopting the technology provided by the invention.
The invention is suitable for various flue gas conditions, including SO2Too low, too high or unstable concentration. Adjustment of SO by design2The scale of the absorption-desorption system can realize the preparation of the ultrapure SO from the flue gas under various conditions2The gas can always meet the acid preparation condition of a contact method after being distributed, so that various sulfur-containing flue gases which cannot prepare acid originally can also prepare refined acid, the operation cost is reduced, and benefits are created for enterprises.
The contents of impurities such as acid chromaticity, ignition residues, chlorides, nitrates, amine salts, metal ions, reducing substances and the like of the finished product completely reach the indexes of pure sulfuric acid of GB/T625-. Preparation of ultrapure SO by absorption-desorption2Preparation of ultrapure SO by gas, gas distribution and conversion3And blowing off and oxidizing after absorption to ensure that the product completely reaches the standard of analytically pure sulfuric acid.
The acid impurity content of the drying tower and the acid production absorption tower of the invention reaches the analytical purity level, and the acid concentration can be adjusted to realize the preparation of the analytical pure sulfuric acid without producing industrial sulfuric acid.
2. In the method of the invention, the preparation of the ultrapure sulfur trioxide (namely, the converted gas, steps S3 to S6) is one of the keys of whether the acid production by the gas absorption method can reach the analytically pure sulfuric acid, and in addition, the process steps are mutually coherent and synergically enhanced:
when the flue gas is subjected to impurity removal and temperature reduction, the temperature of the flue gas is reduced to be below 40 ℃ SO as to meet the requirement of SO2Absorbing the required substances while removing SO2Impurities such as external smoke dust (including metal ions), fluorine, chlorine and the like are removed to reach the emission standard;
in the adsorption-desorption process, the organic amine liquid is used to adsorb SO2Specific selectivity of (1), SO absorption by organic amine liquid2After that, SO in the tail gas2The concentration of (A) is up to 50mg/m3Hereinafter, SO2The absorption-desorption system can be adjusted by design to realize the preparation of the ultrapure SO from the flue gas under various conditions2A gas;
mixing ultrapure SO2Mixing with air to distribute gas, and can treat SO in acid-making gas2The concentration is effectively controlled and kept stable, and the preparation of analytically pure sulfuric acid from various kinds of low-sulfur, high-sulfur and unsteady-state flue gases is realized; the obtained acid making gas does not contain nitrogen oxide, and the mass content of nitrate in the prepared analytically pure sulfuric acid is less than 0.00005%; SO in the acid making gas can be obtained by adjusting the gas distribution ratio2The mass content is stably controlled to be 4-6 percent, and the SO can be absorbed by one rotation2The conversion and absorption can be realized by one-time conversion, the conversion rate is more than 95%, and the absorption can be completed by adopting one acid preparation absorption tower, so that the cost can be greatly saved compared with the two-rotation one-absorption and two-rotation two-absorption processes used in the prior art;
the acid making gas is dried by adopting 93 to 95 percent of analytically pure sulfuric acid, so that the water content is less than or equal to 0.1mg/m3Protecting the conversion system equipment and the catalyst, and simultaneously generating dry acid which can adjust the concentration of the absorbed acid and generate analytically pure sulfuric acid through stripping;
the refined acid absorption tower adopts 95-98 percent of analytically pure sulfuric acid to absorb and convert SO in the gas3Adding a medicament for oxidizing and blowing off to remove SO after supplementing dry acid and ultrapure water to adjust the concentration of the acid produced2Reducing impurities are waited, and the product quality completely reaches the index of GB/T625-2007 analytically pure sulfuric acid;
acid making tail gas and stripping waste gas are returned to the acid mist and SO2Absorption-desorption system for recovering unreacted SO2And no additional desulfurizing device is needed.
(3) The system of the invention is designed to be capable of realizing the structure of the method with high efficiency, and has the advantages.
Drawings
FIG. 1 is a process flow chart of a method for preparing analytically pure sulfuric acid from smelting flue gas according to an embodiment of the present invention.
FIG. 2 is a schematic structural diagram of a system for preparing analytically pure sulfuric acid from smelting flue gas according to an embodiment of the present invention.
FIG. 3 is a schematic structural diagram of a conversion system according to an embodiment of the present invention.
Illustration of the drawings:
1. a dynamic wave scrubber; 2. washing the cooling tower; 3. a washing acid cooler; 4. an electric demister; 5. a sulfur dioxide absorption tower; 6. a lean-rich liquid heat exchanger; 7. a sulfur dioxide desorber; 8. a reboiler; 9. a gas distribution tank; 10. a gas distribution filter; 11. a drying tower; 12. a dry acid cooler; 13. a conversion system; 14. SO (SO)3A precision filter; 15. an acid making absorption tower; 16. a acid making cooler; 17. a degassing tower; 18. an air filter; 19. a third heat exchanger; 20. a second heat exchanger; 21. a first heat exchanger; 22. heating an electric furnace; 23. a converter; 24. SO (SO)3A cooler; 25. a first conduit; 26. a second conduit; 27. a gas distribution inlet; 28. a third pipeline; 29. an acid making tail gas outlet; 30. a stripping waste gas outlet; 31. a dry acid outlet; 32. a dry acid inlet; 33. an absorption acid reflux port; 34. an absorption acid outlet; 35. an absorption acid inlet; 36. a dry acid reflux port; 37. a liquid inlet of the degassing tower; 38. an air inlet; 39. a first branch; 40. a second branch circuit; 41. a fourth conduit; 42. a third branch; 43. a fourth branch; 44. a fifth branch; 45. a rich liquid heat exchange outlet; 46. a rich liquid heat exchange inlet; 47. a rich liquid outlet; 48. a rich liquid inlet; 49. a barren liquor outlet; 50. and a barren solution inlet.
Detailed Description
The invention is further described below with reference to the drawings and specific preferred embodiments of the description, without thereby limiting the scope of protection of the invention.
The materials and equipment used in the following examples are commercially available.
Example 1:
the method for preparing analytically pure sulfuric acid by using smelting flue gas disclosed by the invention has the process flow shown in figure 1, and comprises the following steps of:
s1: will contain SO2The smelting flue gas is washed and cooled to capture and remove impurities in the flue gas and is cooled to below 40 ℃ to obtain cooling impurity-removed gas;
s2: cooling the impurity-removed gas, and reducing acid mist until the acid mist is reduced to 5mg/m3Obtaining acid mist reducing gas;
s3: organic amine liquid is used as absorption liquid, and absorption liquid barren solution is adopted to reduce SO in acid mist gas2Adsorbing to remove SO in the gas2The concentration is reduced to 50mg/m3Obtaining rich absorption liquid and tail gas, discharging the tail gas, desorbing the rich absorption liquid to obtain ultrapure SO2Gas and absorption liquid barren solution, and SO in the flue gas after the absorption of the absorption liquid barren solution circulation and acid mist reduction2；
S4: mixing ultrapure SO2Mixing the gas with air to prepare acid-making gas, and preparing SO in the acid-making gas2The mass fraction of (A) is kept between 4 and 6 percent;
s5: drying and absorbing water of acid making gas by adopting analytically pure sulfuric acid with the mass fraction of 93-95 percent to reduce the water content of the acid making gas to 0.1mg/m3Obtaining a dry acid-making gas and a dry acid;
s6: converting the dried acid-making gas under the action of a catalyst to make SO2Conversion to SO3To obtain converted gas, and then filtering;
s7: absorbing the filtered converted gas by adopting analytically pure sulfuric acid with the mass fraction of 95-98% to absorb SO in the converted gas3And adjusting the mass fraction of the absorbed acid to 95% -98%, carrying out oxidation stripping to obtain finished analytically pure sulfuric acid and stripping waste gas, and returning the acid making tail gas and the stripping waste gas to the step S2 for acid mist reduction treatment.
In step S5 of this embodiment, the temperature of the obtained dry acid is reduced to 40 to 60 ℃, the mass fraction of the dry acid is adjusted to 93 to 95%, part of the adjusted dry acid is recycled for drying and water absorption, and the other part of the adjusted dry acid is sent to step S7 to adjust the concentration of the absorbed acid together with the make-up water.
In step S7 of this example, the temperature of the resulting absorption acid was reduced to 60 ℃ to 80 ℃, and the adjusted absorption acid was partially recycled for SO3The part of the solution is sent to step S5 to adjust the concentration of the dry acid, and the remaining part is subjected to degassing treatment.
In step S1 of the present example, washing and cooling were performed in two steps: firstly washing by dynamic wave until the temperature drops to 60-70 ℃, then washing and cooling until the temperature drops to below 40 ℃, and capturing and removing impurities by two times of washing.
In step S6 of this example, the conversion is a primary conversion, specifically a primary tertiary conversion, SO2Conversion to SO3The conversion rate of (a) is 95% or more. The dried acid making gas is heated to 420-450 ℃ and then converted, and the temperature of the obtained converted gas is reduced to 80-180 ℃ and then filtered.
In step S7 of this embodiment, the oxidation stripping includes absorbing SO in the acid with an oxidizing agent2Carrying out oxidation and using air to treat unoxidized SO2And (4) carrying out stripping.
In step S4 and step S7 of the present embodiment, the air is filtered clean air.
Referring to fig. 2, the method for preparing analytically pure sulfuric acid from smelting flue gas according to the embodiment of the present invention can be implemented by using the system, but is not limited to the system.
The system comprises a washing cooling tower 2, an electric demister 4, a sulfur dioxide absorption tower 5, a sulfur dioxide desorption tower 7, a gas distribution tank 9, a drying tower 11, a conversion system 13, an acid making absorption tower 15 and a degassing tower 17 which are sequentially communicated, wherein an absorption liquid rich liquid generated by the sulfur dioxide absorption tower 5 is sent to the sulfur dioxide desorption tower 7 between the sulfur dioxide absorption tower 5 and the sulfur dioxide desorption tower 7, an absorption liquid poor liquid heat exchanger 6 which sends the absorption liquid poor liquid generated by the sulfur dioxide desorption tower 7 to the sulfur dioxide absorption tower 5 and carries out heat exchange of the poor rich liquid is arranged between the sulfur dioxide absorption tower 5 and the sulfur dioxide desorption tower 7, the acid making absorption tower 15 is provided with an acid making tail gas outlet 29, the degassing tower 17 is provided with a stripping waste gas outlet 30, and the acid making tail gas outlet 29 and the stripping waste gas outlet 30 are respectively communicated with.
In this embodiment, the drying tower 11 is provided with a drying acid outlet 31, a drying acid inlet 32 and an absorption acid reflux port 33, the acid making absorption tower 15 is provided with an absorption acid outlet 34, the absorption acid inlet 35 and the dry acid reflux port 36 are arranged on the degassing tower 17, the degassing tower liquid inlet 37 is arranged on the degassing tower 17, the dry acid outlet 31 is communicated with the third pipeline 28, the dry acid cooler 12 is arranged on the third pipeline 28, the third pipeline 28 is respectively provided with a first branch 39 and a second branch 40, the first branch 39 is communicated with the dry acid inlet 32, the second branch 40 is communicated with the dry acid reflux port 36, the absorption acid outlet 34 is communicated with the fourth pipeline 41, the acid making cooler 16 is arranged on the fourth pipeline 41, the fourth pipeline 41 is respectively provided with a third branch 42, a fourth branch 43 and a fifth branch 44, the third branch 42 is communicated with the absorption acid inlet 35, the fourth branch 43 is communicated with the degassing tower liquid inlet 37, and the fifth branch 44 is communicated with the absorption acid reflux port 33.
In this embodiment, the washing cooling tower 2 is provided with a liquid outlet and a liquid inlet, the liquid outlet and the liquid inlet of the washing cooling tower 2 are communicated through a first pipeline 25, and the first pipeline 25 is provided with the washing acid cooler 3.
In this embodiment, sulfur dioxide desorber 7 is equipped with rich liquid heat transfer export 45 and rich liquid heat transfer import 46, and rich liquid heat transfer export 45 communicates through second pipeline 26 with rich liquid heat transfer import 46, is equipped with reboiler 8 on the second pipeline 26.
In this embodiment, the air distribution tank 9 is provided with an air distribution inlet 27, and the air distribution inlet 27 is communicated with an air distribution filter 10.
In this embodiment, the degasser 17 is provided with an air inlet 38, the air inlet 38 being in communication with an air filter 18.
In this embodiment, the system for preparing analytically pure sulfuric acid from smelting flue gas further comprises a dynamic wave scrubber 1, and the dynamic wave scrubber 1 is communicated with an air inlet arranged on the scrubbing cooling tower 2.
In this embodiment, the system for preparing analytically pure sulfuric acid from smelting flue gas further comprises SO3Precision filter 14, conversion system 13 and acid making suckerSO passes between the collecting towers 153The precision filter 14 is in communication.
In this embodiment, the conversion system 13 includes a converter 23 and a heat exchange assembly which are communicated with each other, and the converter 23 is a three-stage converter. The internal structure design mode of the conversion system 13 is conventional knowledge, and as shown in fig. 3, a third heat exchanger 19, a second heat exchanger 20, a first heat exchanger 21, a temperature-raising electric furnace 22 and a first-layer (top-layer) inlet of the converter 23 are sequentially communicated and used for conveying the dried acid-making gas from the drying tower 11 to the converter 23; a first layer outlet of the converter 23, a first heat exchanger 21, a second layer of the converter 23, a second heat exchanger 20, a third layer (bottom layer) of the converter 23, a third heat exchanger 19, SO3The coolers 24 are in turn in communication for catalytically converting the dry acid making gas to converted gas and transporting it out of the conversion system 13 to the acid making absorption tower 15.
The method and the system for preparing analytically pure sulfuric acid from smelting flue gas have the following specific working procedures:
will contain SO2The smelting flue gas enters a dynamic wave scrubber 1 (mainly a reverse spray pipe foam area, the structure is the prior art) for pretreatment, SO that the smelting flue gas contains smoke dust (containing metal ions) and fluorine, chlorine and SO3And (trace) and other impurities are captured and removed, and simultaneously, the temperature is initially reduced to 60-70 ℃, and then the obtained product enters a washing and cooling tower 2. In the washing and cooling tower 2, the flue gas reversely contacts with the washing acid on the surface of the filler in the tower to carry out direct heat exchange and cooling, the flue gas heat absorbed by the washing acid is indirectly exchanged with the circulating cooling water of the washing acid cooler 3 to move out of the system, and the washing acid is circularly sprayed. In the present invention, the washing acid means that the flue gas is washed and SO is absorbed at the same time3The dilute sulfuric acid produced. The dynamic wave scrubber 1 can be selectively configured according to the smelting flue gas condition, and for the condition that the flue gas temperature is higher than 120 ℃ or the smoke content in the flue gas is higher, the dynamic wave scrubber 1 needs to be configured, and for other conditions, only the washing cooling tower 2 needs to be configured.
The flue gas (also used as cooling impurity-removing gas) discharged from the washing and cooling tower 2 enters the electric demister 4, so that the acid mist in the flue gas is deflected and captured and removed when passing through an electric field generated by the honeycomb tubes of the electric demister 4, and the obtained acid mist-reducing gas enters the sulfur dioxide absorption tower 5.
The organic amine liquid in the sulfur dioxide absorption tower 5 has the function of controlling SO2The specific selectivity of the acid mist reducing agent, the SO in the acid mist gas2Absorbed and stored in the rich liquid, and the smoke, fluorine, chlorine, metal ions and SO in the acid mist reducing gas3、SO2And the pollutants are removed, and the tail gas directly reaches the standard and is discharged outside. The rich solution generated by the sulfur dioxide absorption tower 5 enters a sulfur dioxide desorption tower 7 after being preheated by a lean rich solution heat exchanger 6, and the absorption liquid rich solution and the low-pressure steam of a matched reboiler 8 indirectly exchange heat to heat up for realizing desorption, so that the impurity-free ultra-pure sulfur dioxide gas and the absorption liquid lean solution are generated. Ultra pure SO2Gas means SO under dry basis conditions2The purity can reach 99.99% (wt) of the gas. The absorption liquid barren solution generated in the sulfur dioxide desorption tower 7 is sent into the sulfur dioxide absorption tower 5 to continuously absorb SO after being cooled by the barren and rich solution heat exchanger 62And the process is circulated.
Mixing and distributing the ultra-pure sulfur dioxide gas and the clean air treated by the distribution filter 10 in the distribution tank 9 to form acid making gas, and adjusting the mixture ratio to ensure that the acid making gas meets the SO requirement of conversion2The concentration is kept stable, and SO in the acid making gas is prepared2SO that the mass fraction of (A) is maintained at 4 to 6% due to SO2The sulfur-containing flue gas with too low or too high concentration or unstable state can realize the acid preparation by the contact method. The gas distribution filter 10 is a precision filter and is commercially available.
The acid making gas enters a drying tower 11 for drying and water absorption, and the drying tower 11 adopts analytically pure sulfuric acid with the mass fraction of 93-95% to spray and absorb moisture in the acid making gas to obtain dry acid making gas and dry acid (concentrated sulfuric acid for drying). The heat absorbed during the drying of the acid making gas is removed out of the system through the indirect heat exchange between the drying acid cooler 12 and the circulating water, 95% -98% of the absorption acid generated by the acid making absorption tower 15 is supplemented to the drying acid with reduced concentration, part of the added drying acid is recycled for drying and water absorption, the other part of the added drying acid is sent to the acid making absorption tower 15 to be used together with the supplementing water for adjusting the concentration of the absorption acid, and the split ratio is determined according to the actual situation and is not limited. The drying tower 11 can be made of steel lined PTFE material, the packing in the drying tower 11 is made of quartz glass packing, and the drying acid cooler 12 is made of Hastelloy alloy, so that secondary pollution is avoided, but the material is not limited to the material.
The dry acid making gas enters the conversion system 13, is heated by a heat exchange assembly matched with the conversion system 13 and then enters the converter 23, and SO is reacted by a catalyst in the converter 232Conversion to SO3The conversion rate can reach more than 95 percent to obtain converted gas, and the converted gas passes through SO3The fine filter 14 performs filtration processing to remove impurities in the gas, and the gas enters the acid making absorption tower 15.
In the acid making absorption tower 15, the SO in the converted gas is absorbed by adopting 95-98 percent of analytically pure sulfuric acid spraying by mass fraction3The heat absorbed by the absorption acid is indirectly transferred and removed out of the system through the circulating cooling water of the acid making cooler 16, and the temperature of the absorption acid is reduced to 60-80 ℃. Adjusting the concentration of the absorbed acid to 95-98% by using the dry acid refluxed from the drying tower 11 and the supplemented ultrapure water, and recycling the increased absorbed acid part for SO3The partial acid is sent to the drying tower 11 to adjust the concentration of the drying acid, and the rest is degassed, wherein the split ratio is determined according to the actual situation and is not limited. The acid making absorption tower 15 can be made of steel lined PTFE material, the packing of the acid making absorption tower 15 is made of quartz glass packing, and the acid making cooler 16 (which can also be a refined acid cooler) is made of Hastelloy, but the invention is not limited thereto. Both the dry acid and the absorbed acid are of analytical grade, and the acid concentration can be adjusted by mutual interaction.
Part of absorption acid generated by the acid making absorption tower 15 is sprayed into the degassing tower 17 from the upper part, clean air filtered by an air filter 18 (which can adopt an air precision filter) is introduced into the tower bottom, and the clean air and the absorption acid are in reverse contact to react on SO2Blowing off the gas, and adding an oxidizing agent to remove SO2After deep removal, the acid chroma of the finished product, the ignition residues, the contents of impurities such as fluorine, chlorine, nitrate, amine salt, metal ions, reducing substances and the like all reach the index of the analytically pure sulfuric acid, and finally, the analytically pure sulfuric acid is conveyed to an analytically pure sulfuric acid storage tank.
The tail gas of the acid making discharged from the acid making absorption tower 15 and the blow-off waste gas generated by the blow-off of the degassing tower 17 enter the electric demister 4SO that residual SO in tail gas and waste gas2The absorption and reuse treatment is carried out, and the discharge reaches the standard.
So far, the sulfur-containing smelting flue gas enters the system from the dynamic wave scrubber 1, and the process is completed after the whole closed cycle of purification, gas distribution, drying, conversion and absorption is completed.
Example 2:
the method for preparing analytically pure sulfuric acid by using the smelting flue gas (application example) disclosed by the invention has the advantages that the conditions of the smelting flue gas are shown in table 1, the method is implemented by using the system for preparing analytically pure sulfuric acid by using the smelting flue gas in example 1, the process flow is shown in figure 1, the system structure is shown in figure 2, and the method comprises the following steps:
TABLE 1 astable SO2Concentration case flue gas condition table
S1: pretreatment (impurity removal and temperature reduction): the sulfur-containing smelting flue gas with the temperature of 300 ℃ passes through a dynamic wave scrubber 1 and a washing cooling tower 2 in sequence, SO that the smoke dust, fluorine ions, chlorine ions and SO in the flue gas are efficiently removed3And the temperature of the flue gas is reduced to 60-70 ℃ in the dynamic wave washer 1, and is reduced to below 40 ℃, preferably 30-40 ℃ in the washing cooling tower 2.
S2: acid mist reduction: the acid mist in the flue gas discharged from the washing cooling tower 2 is reduced to 5mg/m by an electric demister 43The following.
S3: ultra pure SO2Preparation of gas: the flue gas with acid mist reduced is sent to a sulfur dioxide absorption tower 5, organic amine liquid is used as absorption liquid, and SO in the absorption liquid is absorbed by absorption liquid barren solution2To make SO2The concentration is reduced to 50mg/m3Hereinafter, the rich absorption liquid and the tail gas are obtained. Smoke and SO in tail gas2、SO3Heavy metal ions, fluorine, chlorine and the like reach the emission standard, and tail gas can be directly discharged. The absorption liquid rich solution generated by absorption enters a sulfur dioxide desorption tower 6 for desorption, and the rich solution can be heated up to realize desorption through low-pressure steam heat exchange of a reboiler 7 to obtain the ultrapure SO2Gas and absorption liquid barren solution, the absorption liquid barren solution is returned to the sulfur dioxide absorption tower 5 to continuously absorb SO2And the process is circulated.
For flue gas SO2The spraying amount of absorption liquid barren liquor in the sulfur dioxide absorption tower 5 in the high sulfur period is 70m under the condition of unstable concentration3H, the spraying amount of the absorption liquid rich solution in the sulfur dioxide desorption tower 6 is 60m3The spraying amount of absorption liquid barren liquor in the low sulfur stage sulfur dioxide absorption tower 5 is 20m3H, the spraying amount of the absorption liquid rich solution in the sulfur dioxide desorption tower 6 is 60m3H, leading SO in tail gas discharged by the sulfur dioxide absorption tower 52The concentration is always 50mg/m3The sulfur dioxide desorber 6 is then steadily desorbed to produce 2136kg/h of ultrapure SO2A gas.
S4: preparing acid-making gas: the ultra-pure SO generated by the sulfur dioxide desorption tower 62Gas and 12000m3The clean air treated by the gas distribution precision filter 9 is sent to the gas distribution tank 9 to be mixed, SO that the SO in the mixed gas2The mass fraction of (A) is stably kept at 6% as an acid-making gas.
S5: and (3) drying: sending the acid making gas into a drying tower 11, spraying and drying the acid making gas by using analytically pure sulfuric acid with the mass fraction of 95 percent to absorb water, and reducing the water content of the acid making gas to 0.1mg/m3The dry acid-producing gas and the dry acid are obtained as follows. The dried acid is recycled by heat exchange with circulating cooling water of the dried acid cooler 12 to reduce the temperature to 40 ℃, and analytically pure sulfuric acid (absorption acid) with the mass fraction of 98% generated by the acid making absorption tower 15 is supplemented to the dried acid with the reduced concentration.
S6: and (3) transformation: the dried acid making gas is heated to 420 ℃ through the hot side of a heat exchange assembly matched with the conversion system 13, then enters a converter 23 (a third-stage converter), is subjected to third-stage conversion in the converter 23 under the action of a catalyst, and is subjected to 95% SO2Conversion to SO3Obtaining reformed gas, then reducing the temperature of the reformed gas to 160 ℃ through cold air heat exchange of the heat exchange assembly, and sending the reformed gas to SO3The ultrafilter 14 is subjected to filtration treatment to remove impurities such as catalyst powder, and the filtered converted gas is sent to the acid production absorption tower 15.
Specifically, the three-stage conversion process can be implemented by using the conversion system 13 shown in fig. 3, the conversion system 13 is mainly composed of the converter 22 and a heat exchange assembly, the internal structure arrangement of the conversion system 13 is conventional, and the work flow is as follows: the temperature of the dried acid-making gas sequentially rises from 65 ℃ to 275 ℃ below zero through the tube pass of the third heat exchanger 19, the temperature of the tube pass of the second heat exchanger 20 rises from 275 ℃ below zero to 315 ℃ below zero, the tube pass of the first heat exchanger 21 rises from 315 ℃ to 420 ℃ below zero, the dried acid-making gas enters the converter 23 for the first layer of primary conversion, the temperature of the shell pass of the first heat exchanger 21 is reduced from 554 ℃ to 450 ℃ below zero, the dried acid-making gas enters the converter 23 for the second layer of secondary conversion, the temperature of the shell pass of the second heat exchanger 20 is reduced from 480 ℃ to 440 ℃, the dried acid-making gas enters the converter 23 for the third layer of tertiary conversion, the temperature of the shell pass of the third heat exchanger 19 is reduced from 446 ℃ to3The shell side temperature of the cooler 24 is reduced from 245 ℃ to 160 ℃. The electric heating furnace 22 is used for heating the gas by electric heating when the temperature of the gas entering the converter is insufficient.
S7: preparation of absorption acid: the acid making absorption tower 15 adopts 98 percent of analytically pure sulfuric acid spray to absorb SO in the converted gas3And obtaining absorption acid and acid making tail gas. The temperature of the absorption acid is reduced to 70 ℃ for recycling through the heat exchange of circulating cooling water of the acid making cooler 16, the concentration increased by the absorption acid is regulated back through the drying acid with the mass fraction of 95% returned by the drying tower 11 and the supplemented ultrapure water, one part of the absorption acid goes to the drying tower 11 to regulate the concentration of the drying acid, and the other part of the absorption acid circularly sprays SO of the absorption conversion gas3And the rest goes to a degassing tower 17 for oxidation stripping.
S8: adding oxidant (hydrogen peroxide) into the degassing tower 17 to absorb SO in the acid2By oxidation to SO3Dissolved in the absorption acid and simultaneously blown with clean air treated by the air filter 18 to blow off the unoxidized SO2And obtaining finished acid and blow-off waste gas, wherein the finished acid is analytically pure sulfuric acid and is conveyed into an analytically pure sulfuric acid storage tank. The tail gas after acid making absorption and the blow-off waste gas generated by the blow-off of the degassing tower 17 are returned to the electric demister 4 in the step S2, mixed with the cooling impurity-removing gas for acid mist reduction, and then absorbed by sulfur dioxideThe tower 5 absorbs unconverted SO in the acid making tail gas2And stripping SO in the exhaust gas2。
In this embodiment, the acid production system produces 3 tons of analytically pure sulfuric acid per hour, the annual production of the analytically pure sulfuric acid reaches 24000 tons, the quality of the finished product acid completely reaches the indexes of the analytically pure sulfuric acid, and the detection parameters are as shown in the following table 2:
TABLE 2 comparison table of acid detection parameters of finished products produced by system and indexes of GB/T625-2007 analytically pure sulfuric acid
| Name (R) | GB/T625-2007 analytically pure sulfuric acid | Systematic production of finished acid |
| Content (H)2SO4).ω/％ | 95.0-98.0 | 96.5 |
| Chroma. Hazen unit | ≤10 | 2 |
| Ignition residue (in sulfate salt). omega/% ] | ≤0.001 | 0.0007 |
| Chloride (Cl). omega/%) | ≤0.00003 | 0.00002 |
| Nitrate (NO)3).ω/％ | ≤0.00005 | 0.00003 |
| Amine liquid (NH)4).ω/％ | ≤0.0002 | 0.0001 |
| Iron (Fe). omega/% ] | ≤0.00005 | 0.00002 |
| Copper (Cu). omega/%) | ≤0.00001 | —— |
| Arsenic (As), omega/%) | ≤0.000003 | —— |
| Lead (Pb). omega/% ] | ≤0.00001 | 0.000001 |
| Reduction of potassium permanganate species (with SO)2Meter), ω/%) | ≤0.0005 | 0.0003 |
For other SO2Under the condition of flue gas with too low and too high concentration, the scales of the sulfur dioxide absorption tower 5 and the sulfur dioxide desorption tower 7 and the spraying amount thereof are designed and adjusted, so that the acid making gas can always meet the acid making condition of a contact method, and tail gas directly reaches the standard and is discharged when various kinds of flue gas are used for preparing and analyzing pure sulfuric acid.
The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make many possible variations and modifications to the disclosed embodiments, or equivalent modifications, without departing from the spirit and scope of the invention, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention.
Claims (10)
1. A method for preparing analytically pure sulfuric acid from smelting flue gas is characterized by comprising the following steps:
s1: will contain SO2The smelting flue gas is washed and cooled to capture and remove impurities in the flue gas and is cooled to below 40 ℃ to obtain cooling impurity-removed gas;
s2: cooling the impurity-removed gas, and reducing acid mist until the acid mist is reduced to 5mg/m3Obtaining acid mist reducing gas;
s3: organic amine liquid is used as absorption liquid, and absorption liquid barren solution is adopted to reduce SO in acid mist gas2Adsorbing to remove SO in the gas2The concentration is reduced to 50mg/m3Obtaining rich absorption liquid and tail gas, discharging the tail gas, desorbing the rich absorption liquid to obtain ultrapure SO2Gas and absorption liquid barren solution, and SO in the flue gas after the absorption of the absorption liquid barren solution circulation and acid mist reduction2；
S4: mixing ultrapure SO2Mixing the gas with air to prepare acid-making gas, and preparing SO in the acid-making gas2The mass fraction of (A) is kept between 4 and 6 percent;
s5: drying and absorbing water of acid making gas by adopting analytically pure sulfuric acid with the mass fraction of 93-95 percent to reduce the water content of the acid making gas to 0.1mg/m3Obtaining a dry acid-making gas and a dry acid;
s6: the dried acid-making gas acts as a catalystThen converting to SO2Conversion to SO3To obtain converted gas, and then filtering;
s7: absorbing the filtered converted gas by adopting analytically pure sulfuric acid with the mass fraction of 95-98% to absorb SO in the converted gas3And adjusting the mass fraction of the absorbed acid to 95% -98%, carrying out oxidation stripping to obtain finished analytically pure sulfuric acid and stripping waste gas, and returning the acid making tail gas and the stripping waste gas to the step S2 for acid mist reduction treatment.
2. The method for preparing analytically pure sulfuric acid from metallurgical off-gas according to claim 1, wherein in step S5, the temperature of the obtained dry acid is reduced to 40 ℃ to 60 ℃, the mass fraction of the dry acid is adjusted to 93% to 95%, the adjusted dry acid is partially recycled for drying and water absorption, and the other part is sent to step S7 to adjust the concentration of the absorption acid together with the make-up water;
in the step S7, the temperature of the obtained absorption acid is reduced to 60-80 ℃, and the adjusted absorption acid is partially recycled for SO3The part of the solution is sent to step S5 to adjust the concentration of the dry acid, and the remaining part is subjected to degassing treatment.
3. The method for preparing analytically pure sulfuric acid from metallurgical off-gas according to claim 1, wherein in step S1, the scrubbing cooling is performed in two steps: firstly washing by dynamic wave until the temperature drops to 60-70 ℃, then washing and cooling until the temperature drops to below 40 ℃, and capturing and removing the impurities by two times of washing.
4. The method for preparing analytically pure sulfuric acid from metallurgical off-gas according to claim 1, wherein in step S6, the conversion is a primary conversion, the SO2Conversion to SO3The conversion rate of (a) is more than 95%; and/or the dry acid making gas is heated to 420-450 ℃ firstly and then is converted, and the temperature of the obtained converted gas is reduced to 80-180 ℃ and then is filtered.
5. The method for preparing analytically pure sulfuric acid from smelting flue gas according to any one of claims 1 to 4, wherein in the step S7, the oxidation stripping comprises absorbing SO in acid with an oxidant2Carrying out oxidation and using air to treat unoxidized SO2And (4) carrying out stripping.
6. The method for preparing analytically pure sulfuric acid from metallurgical off-gas according to claim 5, wherein in step S4 and step S7, the air is filtered clean air.
7. A system for preparing analytically pure sulfuric acid from smelting flue gas is characterized by comprising a washing cooling tower (2), an electric demister (4), a sulfur dioxide absorption tower (5), a sulfur dioxide desorption tower (7), a gas distribution tank (9), a drying tower (11), a conversion system (13), an acid production absorption tower (15) and a degassing tower (17) which are sequentially communicated, wherein a lean-rich solution heat exchanger (6) for conveying absorption liquid rich solution generated by the sulfur dioxide absorption tower (5) to the sulfur dioxide desorption tower (7), conveying absorption liquid lean solution generated by the sulfur dioxide desorption tower (7) to the sulfur dioxide absorption tower (5) and carrying out lean solution heat exchange is arranged between the sulfur dioxide absorption tower (5) and the sulfur dioxide desorption tower (7), the acid production absorption tower (15) is provided with an acid production tail gas outlet (29), the degassing tower (17) is provided with a stripping waste gas outlet (30), the acid making tail gas outlet (29) and the stripping waste gas outlet (30) are respectively communicated with a gas inlet arranged on the electric demister (4).
8. The system for preparing analytically pure sulfuric acid from smelting flue gas according to claim 7, wherein the drying tower (11) is provided with a drying acid outlet (31), a drying acid inlet (32) and an absorption acid return port (33), the acid making absorption tower (15) is provided with an absorption acid outlet (34), an absorption acid inlet (35) and a drying acid return port (36), the degassing tower (17) is provided with a degassing tower liquid inlet (37), the drying acid outlet (31) is communicated with a third pipeline (28), the third pipeline (28) is provided with a drying acid cooler (12), the third pipeline (28) is respectively provided with a first branch (39) and a second branch (40), the first branch (39) is communicated with the drying acid inlet (32), the second branch (40) is communicated with the drying acid return port (36), and the absorption acid outlet (34) is communicated with a fourth pipeline (41), be equipped with system acid cooler (16) on fourth pipeline (41), fourth pipeline (41) branch is equipped with third branch road (42), fourth branch road (43) and fifth branch road (44), third branch road (42) with absorption acid import (35) intercommunication, fourth branch road (43) with degasser inlet (37) intercommunication, fifth branch road (44) with absorption acid backward flow mouth (33) intercommunication.
9. The system for preparing and analyzing pure sulfuric acid from smelting flue gas according to claim 7 or 8, wherein the washing and cooling tower (2) is provided with a liquid outlet and a liquid inlet, the liquid outlet and the liquid inlet of the washing and cooling tower (2) are communicated through a first pipeline (25), and a washing acid cooler (3) is arranged on the first pipeline (25);
the sulfur dioxide desorption tower (7) is provided with a rich liquid heat exchange outlet (45) and a rich liquid heat exchange inlet (46), the rich liquid heat exchange outlet (45) is communicated with the rich liquid heat exchange inlet (46) through a second pipeline (26), and a reboiler (8) is arranged on the second pipeline (26);
the gas distribution tank (9) is provided with a gas distribution inlet (27), and the gas distribution inlet (27) is communicated with a gas distribution filter (10);
the degassing tower (17) is provided with an air inlet (38), and the air inlet (38) is communicated with an air filter (18).
10. The system for preparing analytically pure sulfuric acid from smelting flue gas according to claim 7 or 8, further comprising a dynamic wave scrubber (1), wherein the dynamic wave scrubber (1) is communicated with an air inlet arranged on the scrubbing cooling tower (2);
the system for preparing analytically pure sulfuric acid by using the smelting flue gas also comprises SO3A precision filter (14), wherein SO passes between the conversion system (13) and the acid making absorption tower (15)3The precision filter (14) is communicated;
the conversion system (13) comprises a converter (23) and a heat exchange assembly which are communicated with each other, and the converter (23) is a three-stage converter.
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| CN113082946A (en) * | 2021-04-08 | 2021-07-09 | 成都达奇环境科技有限公司 | Method for treating waste gas from non-ferrous metal smelting |
| CN113104817A (en) * | 2021-05-14 | 2021-07-13 | 钟祥市大生化工有限公司 | Production method and production device for refining 98% sulfuric acid for electronic industry |
| CN113213433A (en) * | 2021-04-14 | 2021-08-06 | 中国恩菲工程技术有限公司 | Method for directly preparing sulfuric acid for storage battery by using secondary lead smelting flue gas |
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| CN113082946A (en) * | 2021-04-08 | 2021-07-09 | 成都达奇环境科技有限公司 | Method for treating waste gas from non-ferrous metal smelting |
| CN113213433A (en) * | 2021-04-14 | 2021-08-06 | 中国恩菲工程技术有限公司 | Method for directly preparing sulfuric acid for storage battery by using secondary lead smelting flue gas |
| CN113104817A (en) * | 2021-05-14 | 2021-07-13 | 钟祥市大生化工有限公司 | Production method and production device for refining 98% sulfuric acid for electronic industry |
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