CN109553152B - Stainless steel mixed acid waste liquid regenerated acid process - Google Patents
Stainless steel mixed acid waste liquid regenerated acid process Download PDFInfo
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- CN109553152B CN109553152B CN201811459327.XA CN201811459327A CN109553152B CN 109553152 B CN109553152 B CN 109553152B CN 201811459327 A CN201811459327 A CN 201811459327A CN 109553152 B CN109553152 B CN 109553152B
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/16—Treatment of water, waste water, or sewage by heating by distillation or evaporation using waste heat from other processes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D47/00—Separating dispersed particles from gases, air or vapours by liquid as separating agent
- B01D47/06—Spray cleaning
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/68—Halogens or halogen compounds
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/77—Liquid phase processes
- B01D53/78—Liquid phase processes with gas-liquid contact
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/10—Treatment of water, waste water, or sewage by heating by distillation or evaporation by direct contact with a particulate solid or with a fluid, as a heat transfer medium
- C02F1/12—Spray evaporation
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/16—Nitrogen compounds, e.g. ammonia
- C02F2101/163—Nitrates
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/16—Nature of the water, waste water, sewage or sludge to be treated from metallurgical processes, i.e. from the production, refining or treatment of metals, e.g. galvanic wastes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02C20/00—Capture or disposal of greenhouse gases
- Y02C20/30—Capture or disposal of greenhouse gases of perfluorocarbons [PFC], hydrofluorocarbons [HFC] or sulfur hexafluoride [SF6]
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
Abstract
The invention belongs to the technical field of regeneration of mixed acid waste liquid, and relates to a regeneration acid process of stainless steel mixed acid waste liquid, wherein the mixed acid waste liquid enters a pre-concentration displacement device for pre-concentration treatment and displacement reaction; HF gas is absorbed by water to form hydrofluoric acid, and the hydrofluoric acid and metal nitrate in the mixed acid waste liquid are subjected to displacement reaction to generate nitric acid and fluoride; directly contacting the mixed acid waste liquid with high-temperature flue gas generated by high-temperature decomposition in a reaction furnace for heat exchange, evaporating nitric acid in the mixed acid waste liquid into the high-temperature flue gas to obtain a concentrated solution of the mixed acid waste liquid, and washing and separating solid particles in the high-temperature flue gas; the concentrated solution of the mixed acid waste liquid enters a reaction furnace for pyrolysis; the high-temperature flue gas after dust separation enters an absorption tower, and HF and HNO in the high-temperature flue gas are leached by water spraying3Absorbed by water to form regenerated acid. The invention provides a regeneration method of stainless steel mixed acid waste liquidThe acid process carries out pre-concentration treatment and replacement reaction in a pre-concentration replacement device, and improves the recovery rate of the nitric acid.
Description
Technical Field
The invention belongs to the technical field of regeneration of mixed acid waste liquid, and particularly relates to a regeneration acid process of stainless steel mixed acid waste liquid.
Background
The steel and mechanical processing industry generally adopts the mixed solution of nitric acid and hydrofluoric acid to carry out chemical pickling on stainless steel so as to remove iron scales and chromium-poor layers of the stainless steel, and the following reactions occur when base metals, the chromium-poor layers and metal oxides are dissolved:
Fe+HNO3＝Fe(NO3)3+NO+2H2O
Fe(NO3)3+3HF→FeF3+3HNO3
Fe2O3+6HNO3＝2Fe(NO3)3+3H2O
FeO+4HNO3＝2Fe(NO3)3+2H2O+NO2
Fe3O4+10HNO3＝3Fe(NO3)3+5H2O+NO2
Fe(NO3)3+3HF＝FeF3+3HNO3
MexOy+HNO3→Me(NO3)z+H2O
MexOy+HF→MeFz+H2O
……
(Me indicates a metal element other than iron)
The mixed acid waste liquid after acid cleaning contains a large amount of metal nitrate, metal fluoride, and incompletely reacted nitric acid and hydrofluoric acid. At present, a spray roasting method (or a fluidized bed method) is commonly adopted to regenerate the stainless steel waste mixed acid waste liquid, the regeneration process comprises the steps of providing fuel gas and combustion-supporting air for a reaction furnace, providing a combustion heat source for the reaction furnace through combustion, spraying the concentrated mixed acid waste liquid into the reaction furnace, and carrying out the following decomposition reaction in a high-temperature furnace:
H2o (liquid) ═ H2O (gas)
HNO3(aqueous solution) ═ HNO3(gas); evaporation of nitric acid
HF (aqueous solution) ═ HF (gas); evaporation of hydrofluoric acid
2FeF3+3H2O＝Fe2O3+6HF
2Fe(NO3)3+3H2O＝Fe2O3+6HNO3；
MeFx+H2O→MeyOz+ HF; decomposition of fluoride
Me(NO3)x+H2O→MeyOz+HNO3(ii) a Decomposition of nitrate
2HNO3(gas) ═ NO2(gas) + H2O (gas) + O2(gas); decomposition of nitric acid
NO2＝NO+1/2O2
……
(Me indicates a metal element other than iron)
The reaction furnace gas is composed of water vapor, HF, NOxThe gas and the combustion waste gas are separated from the top of the reaction furnace and enter the preconcentrator, and the mixed acid waste liquid is sprayed out from the bottom of the preconcentrator and then sprayed from the top to form a loop. In the preconcentrator, the gas of the high-temperature reaction furnace directly contacts with the circulating spray liquid of the preconcentrator for heat exchange, and part of HNO in the mixed acid waste liquid3The nitric acid is evaporated into the flue gas in the heat exchange with the high-temperature flue gas, and the circulating acid liquid is concentrated by the evaporation of part of the acid liquid. The flue gas containing nitric acid gas is separated from dust and then enters an absorption tower to be absorbed by waterForming a regenerating acid.
By adopting the process, the mixed acid waste liquid directly enters the preconcentrator for concentration, part of free nitric acid is evaporated in the preconcentrator, and the waste liquid sprayed into the reaction furnace mainly comprises metal nitrate and fluoride salt. Decomposition of nitrate to NO in the roasting process of the reaction furnacexContaining NOxCooling the flue gas, oxidizing and recovering part of HNO by an oxidation tower3Introduction of NO intoxThe conversion to nitric acid requires lower temperature, and the conversion efficiency and the recovery rate of nitric acid are low. While not recovering NOxThe flue gas needs to be heated and converted into N in the denitration reactor2Not only a large amount of cooling water and fuel gas need to be consumed, but also a large amount of denitration agent (ammonia water or urea) needs to be consumed, and the operation cost is increased.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention aims to provide a stainless steel mixed acid waste liquid regenerated acid process, which can effectively improve the recovery rate of nitric acid and reduce the consumption of ammonia water or urea serving as a denitrifying agent.
In order to achieve the purpose, the technical scheme of the invention is a stainless steel mixed acid waste liquid regenerated acid process, wherein the mixed acid waste liquid enters a pre-concentration displacement device for pre-concentration treatment and displacement reaction; HF gas in high-temperature flue gas generated by the reaction furnace is absorbed by water to form hydrofluoric acid, and the hydrofluoric acid and metal nitrate in the mixed acid waste liquid are subjected to a displacement reaction to generate nitric acid and fluoride; directly contacting the mixed acid waste liquid with high-temperature flue gas generated by high-temperature decomposition in a reaction furnace for heat exchange, evaporating hydrofluoric acid and nitric acid in the mixed acid waste liquid into the high-temperature flue gas to obtain a concentrated solution of the mixed acid waste liquid, and washing and separating solid particles in the high-temperature flue gas; the concentrated solution of the mixed acid waste liquid enters a reaction furnace for pyrolysis;
the high-temperature flue gas after dust separation enters an absorption tower, and HF gas and HNO in the high-temperature flue gas are leached by spraying water3The gas is absorbed by the water to form a regenerated acid.
As an implementation mode, the mixed acid waste liquid enters a nitric acid displacement tower of a pre-concentration displacement device in a spraying mode, HF gas in high-temperature flue gas from a pre-concentrator of the pre-concentration displacement device is absorbed by water to form hydrofluoric acid, the hydrofluoric acid and metal nitrate in the mixed acid waste liquid are subjected to displacement reaction, generated nitric acid and fluoride salt enter the mixed acid waste liquid, then the mixed acid waste liquid enters the pre-concentrator of the pre-concentration displacement device in a spraying mode and directly contacts with high-temperature flue gas generated in a reaction furnace to perform heat exchange, nitric acid in the mixed acid waste liquid is evaporated into the high-temperature flue gas to obtain concentrated liquid of the mixed acid waste liquid, and meanwhile solid particles in the high-temperature flue gas are washed and separated; and the concentrated solution of the mixed acid waste liquid enters a reaction furnace for pyrolysis.
And further, after the generated nitric acid and fluoride salt enter the mixed acid waste liquid, the mixed acid waste liquid enters a nitric acid displacement tower in a spraying mode to perform displacement reaction.
As an implementation mode, the mixed acid waste liquid enters a preconcentrator of a preconcentration displacement device in a spraying mode and directly contacts with high-temperature flue gas generated in a reaction furnace for heat exchange, nitric acid in the mixed acid waste liquid is evaporated into the high-temperature flue gas, and a concentrated solution of the mixed acid waste liquid is obtained; then the high-temperature flue gas enters a nitric acid displacement tower of the pre-concentration displacement device and is washed by the sprayed mixed acid waste liquid, HF gas in the high-temperature flue gas is absorbed by water to form hydrofluoric acid, the hydrofluoric acid and metal nitrate in the mixed acid waste liquid are subjected to displacement reaction, the generated nitric acid and fluoride salt enter the mixed acid waste liquid, and then the nitric acid and fluoride salt return to a pre-concentrator for pre-concentration treatment.
Furthermore, the inlet flue gas temperature of the nitric acid displacement tower is 85-95 ℃, and the outlet flue gas temperature is 65-85 ℃.
Further, high-temperature flue gas generated by pyrolysis in the reaction furnace contains water vapor, HF gas and HNO3Gas, NOxA gas.
Further, the solid powder produced in the reaction furnace is conveyed to an oxide bin for storage through an oxide conveying device connected with the bottom of the reaction furnace.
Further, flue gas from the absorption tower enters a venturi dust collector for spraying, washing and purifying, then enters a spraying cooling tower for spraying, cooling and cooling, the cooled flue gas enters an oxidation tower for oxidation treatment, and then enters a denitration reactor for denitration treatment, and the flue gas is discharged into the atmosphere after reaching the standard.
Further, the temperature of the high-temperature flue gas generated in the reaction furnace is 200-300 ℃.
Compared with the prior art, the invention has the following beneficial effects:
(1) the stainless steel mixed acid waste liquid regenerated acid process provided by the invention carries out pre-concentration treatment and nitric acid replacement reaction in the pre-concentration replacement device, and releases more HNO in the pre-concentration replacement device3The recovery rate of the nitric acid is improved;
(2) according to the stainless steel mixed acid waste liquid regenerated acid process, nitric acid and fluoride salt are generated through the replacement reaction of hydrofluoric acid and metal nitrate in the mixed acid waste liquid, and the metal nitrate is prevented from being decomposed into NO in a roasting furnacexThe load of the denitration device is increased, the denitration agent and the energy consumption are increased, and the operating cost is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a flow chart of a process for regenerating acid from stainless steel mixed acid waste liquid according to an embodiment of the present invention;
FIG. 2 is a flow chart of a process for regenerating acid from stainless steel mixed acid waste liquid provided by the second embodiment of the present invention;
FIG. 3 is a flow chart of a process for regenerating acid from stainless steel mixed acid waste liquid provided by the third embodiment of the present invention;
FIG. 4 is a flow chart of a process for regenerating acid from stainless steel mixed acid waste liquid provided by the second embodiment of the present invention;
in the figure: 1. the system comprises a reaction furnace, 2, an oxide conveying device, 3, a preconcentrator, 4, a preconcentrator circulating pump, 5, a reaction furnace feeding pump, 6, a mixed acid waste liquid flow regulating valve, 7, an absorption tower, 8, a Venturi dust collector, 9, a Venturi dust collector circulating pump, 10, a spray cooling tower, 11, a spray cooling tower heat exchanger, 12, a spray cooling tower circulating pump, 13, a waste gas fan, 14, an oxidation tower, 15, an oxidation tower heat exchanger, 16, an oxidation tower circulating pump, 17, a denitration reactor, 18, a chimney, 19, a nitric acid replacement tower, 20 and a nitric acid replacement tower flow regulating valve.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example one
As shown in fig. 1 to 4, an embodiment of the present invention provides a process for regenerating an acid from a stainless steel mixed acid waste liquid, where the mixed acid waste liquid enters a pre-concentration displacement device for pre-concentration treatment and nitric acid displacement reaction; HF gas in the high-temperature flue gas is absorbed by water to form hydrofluoric acid, and the hydrofluoric acid and metal nitrate in the mixed acid waste liquid are subjected to a displacement reaction to generate nitric acid and fluoride salt; directly contacting the mixed acid waste liquid with high-temperature flue gas generated by high-temperature decomposition in the reaction furnace 1 for heat exchange, evaporating hydrofluoric acid and nitric acid in the mixed acid waste liquid into the high-temperature flue gas to obtain concentrated solution of the mixed acid waste liquid, and washing and separating solid particles in the high-temperature flue gas; the concentrated solution of the mixed acid waste liquid enters the reaction furnace 1 for pyrolysis; the high-temperature flue gas after dust separation enters an absorption tower 7, and HF gas and HNO in the high-temperature flue gas are leached by water spraying3The gas is absorbed by the water to form a regenerated acid. The stainless steel mixed acid waste liquid regenerated acid process provided by the embodiment releases more HNO in the pre-concentration displacement device3The recovery rate of the nitric acid is improved; instead of decomposing the metal nitrate to NO in the calcinerxThen through subsequent cooling and temperature reduction, part of HNO is oxidized and recovered through an oxidation tower 143Thereby to makeReduce NO in the systemxThe load of the denitration device is reduced, the consumption of the denitration agent and the energy consumption are reduced, and the operating cost is reduced.
High-temperature flue gas leaving from the top of the reaction furnace 1 enters a pre-concentration replacement device, mixed acid waste liquid enters the pre-concentration replacement device through a mixed acid waste liquid flow regulating valve 6, and the mixed acid waste liquid in the pre-concentration replacement device is pumped out by a pre-concentrator circulating pump 4 and sprayed into the pre-concentrator 3 from the top to form a loop. In the pre-concentration replacement device, HF gas is absorbed by water to form hydrofluoric acid, and the hydrofluoric acid and metal nitrate in the mixed acid waste liquid are subjected to replacement reaction to generate nitric acid and fluoride; the gas in the high-temperature reaction furnace 1 directly contacts with the mixed acid waste liquid sprayed into the pre-concentration displacement device for heat exchange, and the circulating acid liquid is concentrated due to the evaporation of part of nitric acid and hydrofluoric acid; simultaneously, the mixed acid waste liquid is utilized to wash residual oxide solid particles in the gas to generate Fe (NO)3)3And part of nitric acid in the mixed acid waste liquid is evaporated into the flue gas in the heat exchange with the high-temperature flue gas.
In the preconcentration displacement device, the following reaction takes place:
HF (gas) → HF (aqueous solution); absorption of hydrofluoric acid
Fe(NO3)3+3HF→FeF3+3HNO3(ii) a Replacement by nitric acid
HNO3(aqueous solution) → HNO3(gas); evaporation of nitric acid
Fe2O3+6HNO3→2Fe(NO3)3+3H2O; (Metal oxides in flue gas are dissolved)
MexOy+HNO3→Me(NO3)z+H2O
The gas after cooling and dust separation enters an absorption tower 7, the gas is sprayed and leached by water, the gas is sent from the bottom of the absorption tower 7, and HF gas and HNO in the flue gas are generated in the countercurrent process3The gas is absorbed by the water to form a regenerated acid.
HNO3(gas) → HNO3(aqueous solution); partial absorption of nitric acid
HF (gas) → HF (aqueous solution); absorption of hydrofluoric acid
Further, the high-temperature flue gas generated by the high-temperature decomposition in the reaction furnace 1 contains water vapor, HF gas and HNO3Gas, NOxA gas. As shown in fig. 2 to 4, the gas and the combustion air are supplied to the reaction furnace 1, the combustion heat source is supplied to the reaction furnace 1 by the combustion, and the concentrated waste mixed acid liquid is injected into the reaction furnace 1 by the reaction furnace feed pump 5, so that the decomposition reaction occurs in the high temperature furnace. The temperature of high-temperature flue gas generated in the reaction furnace is 200-300 ℃, the high-temperature flue gas enters the pre-concentration displacement device to exchange heat with the mixed acid waste liquid, and hydrofluoric acid and nitric acid in the mixed acid waste liquid are evaporated into the flue gas.
Further, Fe is a main component generated by pyrolysis2O3The metal oxide solid powder is sent to an oxide bin for storage through an oxide conveying device 2 connected with the bottom of the reaction furnace 1.
Further, flue gas from the absorption tower 7 enters a venturi dust collector 8 for spraying, washing and purifying, then enters a spraying cooling tower 10 for spraying, cooling and cooling, the cooled flue gas enters an oxidation tower 14 for oxidation treatment, and then enters a denitration reactor 17 for denitration treatment, and the flue gas is discharged into the atmosphere after reaching the standard.
The flue gas containing combustion tail gas from the absorption tower 7 and trace acid and NOxAnd the water vapor tail gas of the metal oxide dust passes through a Venturi dust collector 8, and is washed and purified by circulating spray liquid pumped out by a circulating pump 9 of the Venturi dust collector, so that the content of the metal oxide dust and acid in the metal oxide dust is reduced; then the flue gas enters a spray cooling tower 10, the circulating spray liquid pumped out by a circulating pump 12 of the spray cooling tower is used for spray cooling and temperature reduction, and the heat of the circulating spray liquid is brought out by indirect heat exchange with external cooling water through a spray cooling tower heat exchanger 11; the cooled tail gas is pumped into an oxidation tower 14 through a waste gas fan 13 for oxidation, and the following reaction occurs in the oxidation tower 14 to generate partial nitric acid:
NO2+H2O＝2HNO3+NO
NO+1/2O2＝NO2
the generated nitric acid is sprayed and absorbed by circulating spray liquid pumped by a circulating pump 16 of the oxidation tower, and redundant reaction heat and absorption heat are brought out by indirect heat exchange with external cooling water by a heat exchanger 15 of the oxidation tower;
then, the flue gas after the oxidation reaction enters a denitration reactor 17, and is subjected to denitration treatment by spraying a denitration agent (ammonia water or urea), wherein the chemical reaction is as follows:
NO+NO2+2NH3＝2N2+3H2O
4NO+4NH3+O2＝4N2+6H2O
2NO2+4NH3+O2＝4N2+6H2O
and the tail gas subjected to denitration treatment and reaching the standard is discharged into the atmosphere through a chimney 18.
Example two
As shown in fig. 2 and fig. 4, an embodiment of the present invention provides a stainless steel mixed acid waste liquid regenerated acid process, where the mixed acid waste liquid enters a nitric acid displacement tower 19 of a preconcentration displacement device in a spraying manner, so that HF gas in high-temperature flue gas is absorbed by water to form hydrofluoric acid, the hydrofluoric acid and metal nitrate in the mixed acid waste liquid undergo a displacement reaction, the generated nitric acid and fluoride salt enter the mixed acid waste liquid, then the mixed acid waste liquid enters a preconcentrator 3 of the preconcentration displacement device in a spraying manner and directly contacts with high-temperature flue gas generated in a reaction furnace 1 to perform heat exchange, nitric acid in the mixed acid waste liquid is evaporated into the high-temperature flue gas, and a concentrated solution of the mixed acid waste liquid is obtained, and meanwhile, solid particles in the high-temperature flue gas are washed and separated; the concentrated solution of the mixed acid waste liquid enters the reaction furnace 1 for pyrolysis; the high-temperature flue gas after dust separation enters an absorption tower 7, and HF gas and HNO in the high-temperature flue gas are leached by water spraying3The gas is absorbed by the water to form a regenerated acid. In the acid regeneration process for stainless steel mixed acid waste liquid provided by this embodiment, a nitric acid substitution tower 19 is added between the preconcentrator 3 and the absorption tower 7 in the preconcentrator 3 for pre-absorbing the HF gas regenerated by the partial reaction furnace 1, and the pre-absorbed hydrofluoric acid is used to react with Fe (NO) in the mixed acid waste liquid3)3Displacement is carried out to release HNO3Further improve the intake suctionHNO in flue gas before tower 73The concentration of the gas further forms regenerated acid containing nitric acid with higher concentration in the absorption tower 7, thereby avoiding excessive nitrate from entering the reaction furnace 1 to be roasted to generate NOxThe nitric acid recovery rate is influenced, and NO of the subsequent spray cooling tower 10 and the oxidation tower 14 is further reducedxConcentration, reducing the workload of the oxidation tower 14, further reducing the consumption of cooling circulating water, and reducing the amount of NO which is not recovered and enters the denitration reactor 17xThe concentration further reduces the consumption of the denitrifier (ammonia water or urea) and the consumption of fuel gas required by the heating medium, thereby reducing the operation cost.
In the embodiment, the mixed acid waste liquid is input into the nitric acid displacement tower 19 through the mixed acid waste liquid flow regulating valve 6, is sprayed from the top and is used for pre-absorbing partial HF gas and displacing HNO3The nitric acid substitution column 19 may be a hollow column or an absorption column 7 with packing. The flow rate of the solution sprayed into the nitric acid displacement tower 19 can be properly adjusted according to the condition of the mixed acid waste liquid, so as to ensure the smooth proceeding of the displacement reaction of hydrofluoric acid and nitrate. Meanwhile, high-temperature flue gas generated by the reaction furnace 1 leaves from the top of the reaction furnace 1 and enters the preconcentrator 3, the mixed acid waste liquid directly enters the preconcentrator 3 through the mixed acid waste liquid flow regulating valve 6, and is pumped out by the preconcentrator circulating pump 4 and sprayed into the preconcentrator 3 from the top to form a loop. The gas in the high-temperature reaction furnace 1 directly contacts with the circulating spray liquid in the preconcentrator 3 for heat exchange, and the circulating acid liquid is concentrated due to the evaporation of part of the acid liquid; simultaneously, residual oxide solid particles in the gas are washed by the circulating acid liquid to generate Fe (NO)3)3(ii) a Part of nitric acid in the mixed acid waste liquid is evaporated into the flue gas in the heat exchange with the high-temperature flue gas.
The newly added nitric acid displacement tower 19 can be arranged independently of the pre-concentrator 3 and is connected through a flue gas pipeline; it may also be incorporated into the pre-concentrator 3 and placed above the pre-concentrator 3. The reaction in the nitric acid substitution column 19 and the preconcentrator 3 in this embodiment is the same as that in the preconcentration substitution apparatus in the first embodiment, and the principle is the same.
As an implementation manner, as shown in fig. 4, after the generated nitric acid and fluoride salt enter the mixed acid waste liquid, the mixed acid waste liquid is sent to a nitric acid displacement tower 19 through a branch pipe connected to an outlet pipeline of a pre-concentrator circulating pump 4, a flow regulating valve 20 of the nitric acid displacement tower is arranged on the branch pipe, and the mixed acid waste liquid enters the nitric acid displacement tower 19 in a spraying manner to perform a displacement reaction. The flow sprayed into the nitric acid replacement tower 19 can be adjusted jointly through the mixed acid waste liquid flow adjusting valve 6 and the nitric acid replacement tower flow adjusting valve 20 according to the condition of the mixed acid waste liquid, so as to ensure the smooth proceeding of the hydrofluoric acid and nitrate replacement reaction.
Further, in order to ensure the smooth proceeding of pre-absorption, replacement and evaporation, the inlet flue gas temperature of the nitric acid replacement tower 19 is 85-95 ℃, and the outlet flue gas temperature is 65-85 ℃.
The method and principle of treating the flue gas from the absorption tower 7 in this embodiment are the same as those in the first embodiment.
EXAMPLE III
As shown in fig. 3, the mixed acid waste liquid enters the preconcentrator 3 of the preconcentration and displacement device in a spraying manner and directly contacts with the high-temperature flue gas generated in the reaction furnace 1 for heat exchange, the nitric acid in the mixed acid waste liquid is evaporated into the high-temperature flue gas, a concentrated solution of the mixed acid waste liquid is obtained, and meanwhile, solid particles in the high-temperature flue gas are washed and separated; the concentrated solution of the mixed acid waste liquid enters the reaction furnace 1 for pyrolysis; then the high temperature flue gas enters a nitric acid displacement tower 19 of the pre-concentration displacement device and is washed by the sprayed mixed acid waste liquid, HF gas in the high temperature flue gas is absorbed by water to form hydrofluoric acid, the hydrofluoric acid and metal nitrate in the mixed acid waste liquid are subjected to displacement reaction, the generated nitric acid and fluoride salt enter the mixed acid waste liquid, and then the nitric acid and fluoride salt return to the pre-concentrator 3 for pre-concentration treatment. In the acid regeneration process for stainless steel mixed acid waste liquid provided by this embodiment, a nitric acid substitution tower 19 is added between the preconcentrator 3 and the absorption tower 7 in the preconcentrator 3 for pre-absorbing the HF gas regenerated by the partial reaction furnace 1, and the pre-absorbed hydrofluoric acid is used to react with Fe (NO) in the mixed acid waste liquid3)3Displacement is carried out to release HNO3Avoiding excessive nitrate from entering the reaction furnace 1 to be roasted to generate NOxAffecting the nitric acid recovery.
The high-temperature flue gas generated by the reaction furnace 1 in the embodiment leaves from the top of the reaction furnace 1 and enters the pre-concentrator 3,the mixed acid waste liquid directly enters the pre-concentrator 3 through the mixed acid waste liquid flow regulating valve 6, is pumped out by the pre-concentrator circulating pump 4 and is sprayed into the pre-concentrator 3 from the top to form a loop. The gas in the high-temperature reaction furnace 1 directly contacts with the circulating spray liquid in the preconcentrator 3 for heat exchange, and the circulating acid liquid is concentrated due to the evaporation of part of the acid liquid; simultaneously, residual oxide solid particles in the gas are washed by the circulating acid liquid to generate Fe (NO)3)3(ii) a Part of HNO in mixed acid waste liquid3The (nitric acid) is evaporated into the flue gas in heat exchange with the high temperature flue gas. Meanwhile, the mixed acid waste liquid in the preconcentrator 3 is connected with a branch pipe to a nitric acid displacement tower 19 through an outlet pipeline of a preconcentrator circulating pump 4 at the bottom of the preconcentrator 3, a flow regulating valve 20 of the nitric acid displacement tower is arranged on the branch pipe, the mixed acid waste liquid is sprayed from the top and is used for pre-absorbing partial HF gas and displacing nitric acid, and the nitric acid displacement tower 19 can be a hollow tower or an absorption tower 7 with filler.
The newly added nitric acid displacement tower 19 can be arranged independently of the pre-concentrator 3 and is connected through a flue gas pipeline; it may also be incorporated into the pre-concentrator 3 and placed above the pre-concentrator 3. The reaction in the nitric acid substitution column 19 and the preconcentrator 3 in this embodiment is the same as that in the preconcentration substitution apparatus in the first embodiment, and the principle is the same.
Further, in order to ensure the smooth proceeding of pre-absorption, replacement and evaporation, the inlet flue gas temperature of the nitric acid replacement tower 19 is 85-95 ℃, and the outlet flue gas temperature is 65-85 ℃. The flow sprayed into the nitric acid displacement tower 19 can be properly adjusted by the nitric acid displacement tower flow adjusting valve 20 according to the condition of the mixed acid waste liquid, so as to ensure the smooth proceeding of the hydrofluoric acid and nitrate displacement reaction.
The method and principle of treating the flue gas from the absorption tower 7 in this embodiment are the same as those in the first embodiment.
Example four
As shown in fig. 2-4, the embodiment provides a stainless steel mixed acid waste liquid regenerated acid device, which includes a reaction furnace 1, an absorption tower 7, and a pre-concentration and replacement device for performing a hydrofluoric acid and nitrate replacement reaction and pre-concentration treatment on the mixed acid waste liquid; of said preconcentration displacement meansA mixed acid waste liquid inlet is communicated with a mixed acid waste liquid inlet pipe, a concentrated liquid outlet of the pre-concentration displacement device is communicated with a concentrated liquid inlet of the reaction furnace 1, a flue gas outlet of the reaction furnace 1 is communicated with a flue gas inlet of the pre-concentration displacement device, and a flue gas outlet of the pre-concentration displacement device is communicated with a flue gas inlet of the absorption tower 7; the top of the absorption tower 7 is communicated with a spray header, and the bottom of the absorption tower 7 is communicated with a regenerated acid outlet pipe. The stainless steel mixed acid waste liquid regenerated acid equipment provided by the invention performs pre-concentration treatment and nitric acid replacement reaction in the pre-concentration replacement device, and releases more HNO in the pre-concentration replacement device3The recovery rate of the nitric acid is improved; meanwhile, hydrofluoric acid and metal nitrate in the mixed acid waste liquid are subjected to displacement reaction to generate nitric acid and fluoride salt, so that the metal nitrate is prevented from being decomposed into NO in a roasting furnacexThe load of the denitration device is increased, the denitration agent and the energy consumption are increased, and the operating cost is reduced.
Further, the pre-concentration and displacement device comprises a nitric acid displacement tower 19 and a pre-concentrator 3, a flue gas inlet of the pre-concentrator 3 is communicated with a flue gas outlet of the reaction furnace 1, a concentrated solution outlet of the pre-concentrator 3 is communicated with a concentrated solution inlet of the reaction furnace 1, and a flue gas outlet of the nitric acid displacement tower 19 is communicated with a flue gas inlet of the absorption tower 7.
Further, the bottom of the preconcentrator 3 is communicated with a spray liquid pipe at the top of the preconcentrator 3 through a preconcentrator circulating pump 4, and the spray end of the spray liquid pipe is positioned below a flue gas inlet of the preconcentrator 3, so that the mixed acid waste liquid is fully in direct contact with high-temperature flue gas to perform heat exchange, and more nitric acid and hydrofluoric acid in the mixed acid waste liquid are evaporated into the high-temperature flue gas.
Further, the bottom of the reaction furnace 1 is connected to an oxide transfer device 2. The main component generated by pyrolysis is Fe2O3The metal oxide is sent to an oxide bin for storage through an oxide conveying device 2 at the bottom of the reaction furnace 1.
In this embodiment, the mixed acid waste liquid inlet pipe is provided with a mixed acid waste liquid flow regulating valve 6, and the mixed acid waste liquid flow sprayed into the nitric acid displacement tower 19 is regulated by the mixed acid waste liquid flow regulating valve 6, so as to ensure the smooth proceeding of the hydrofluoric acid and nitrate displacement reaction.
Further, the flue gas outlet of the absorption tower 7 is sequentially connected with a venturi dust collector 8, a spray cooling tower 10, an oxidation tower 14 and a denitration reactor 17, and the flue gas is denitrated to reach the standard and then discharged.
As an implementation mode, the exhanst gas outlet of absorption tower 7 communicates with the flue gas inlet of venturi scrubber 8, the liquid outlet of venturi scrubber 8 bottom pass through venturi scrubber circulating pump 9 with the spray liquid pipe intercommunication at 8 tops of venturi scrubber, and the spray end that sprays the liquid pipe is located the below of the exhanst gas inlet of venturi scrubber 8, the exhanst gas outlet of venturi scrubber 8 and the flue gas inlet intercommunication. Circulating liquid in the venturi dust collector 8 enters the top of the venturi dust collector 8 in a spraying mode through a venturi dust collector circulating pump 9, is in direct contact with flue gas entering from a flue gas inlet of the venturi dust collector 8, is sprayed and dedusted, removes solid particles in the flue gas, and the dedusted flue gas enters a spray cooling tower 10.
As an implementation manner, a liquid outlet of the spray cooling tower 10 is communicated with a spray liquid pipe at the top of the spray cooling tower 10 through a circulation pipeline of the spray cooling tower 10, a spray end of the spray liquid pipe is located below a flue gas inlet of the spray cooling tower 10, and a flue gas outlet of the spray cooling tower 10 is communicated with a flue gas inlet of the oxidation tower 14. And a circulating pipeline of the spray cooling tower 10 is provided with a spray cooling tower circulating pump 12 and a spray cooling tower heat exchanger 11, and cooling water of the spray cooling tower heat exchanger 11 enters from top to bottom. Circulating liquid in the spray cooling tower 10 is pumped out by a Venturi dust collector circulating pump 9, then passes through the heat exchange of a spray cooling tower heat exchanger 11, enters the top of the spray cooling tower 10 in a spraying mode, is in direct contact with flue gas entering from a flue gas inlet of the spray cooling tower 10 to be sprayed and cooled, and the cooled flue gas enters an oxidation tower 14.
As an implementation manner, a liquid outlet of the oxidation tower 14 is communicated with a spray liquid pipe at the top of the oxidation tower 14 through a circulation pipeline of the oxidation tower 14, a spray end of the spray liquid pipe is located above a flue gas inlet of the oxidation tower 14, and a flue gas outlet of the oxidation tower 14 is communicated with a flue gas inlet of the denitration reactor 17. An oxidation tower circulating pump 16 and an oxidation tower heat exchanger 15 are arranged on a circulating pipeline of the oxidation tower 14, and cooling water of the oxidation tower heat exchanger 15 is fed from top to bottom. Circulating liquid in the oxidation tower 14 is pumped out by the Venturi dust collector circulating pump 9, then passes through the heat exchange of the oxidation tower heat exchanger 15, enters the top of the oxidation tower 14 in a spraying mode, is in direct contact with flue gas entering from a flue gas inlet of the oxidation tower 14, is subjected to spraying cooling, and enters the denitration reactor 17 for denitration after being cooled.
As an implementation manner, a flue gas outlet of the denitration reactor 17 is communicated with the chimney 18, and the denitration reactor 17 is provided with a denitration agent feeding port; the flue gas entering the denitration reactor 17 reacts with a denitration agent (ammonia water or urea) to generate nitrogen and water, and the flue gas reaching the standard is discharged into the atmosphere through a chimney 18.
The reaction principle of this example is the same as that of the first example.
EXAMPLE five
As shown in fig. 2, the embodiment provides a stainless steel mixed acid waste liquid regenerated acid device, which includes a reaction furnace 1, an absorption tower 7, a nitric acid displacement tower 19 and a preconcentrator 3, where the nitric acid displacement tower 19 and the preconcentrator 3 are split structures, and the mixed acid waste liquid inlet pipe is communicated with a mixed acid waste liquid inlet at the top of the nitric acid displacement tower 19; the mixed acid waste liquid outlet of the nitric acid displacement tower 19 is communicated with the mixed acid waste liquid inlet of the preconcentrator 3, and the flue gas outlet of the preconcentrator 3 is communicated with the flue gas inlet of the nitric acid displacement tower 19; the flue gas inlet of the pre-concentrator 3 is communicated with the flue gas outlet of the reaction furnace 1, the concentrated solution outlet of the pre-concentrator 3 is communicated with the concentrated solution inlet of the reaction furnace 1, and the flue gas outlet of the nitric acid displacement tower 19 is communicated with the flue gas inlet of the absorption tower 7; the top of the absorption tower 7 is communicated with a spray header, and the bottom of the absorption tower 7 is communicated with a regenerated acid outlet pipe. In the stainless steel mixed acid waste liquid regenerated acid equipment provided by the embodiment, the nitric acid replacement tower 19 is additionally arranged between the preconcentrator 3 and the absorption tower 7 of the preconcentrator 3, and is used for pre-absorbing HF gas regenerated by the partial reaction furnace 1, forming hydrofluoric acid with a certain concentration, and simultaneously utilizing the pre-absorbed hydrofluoric acid to react Fe (NO) in the mixed acid waste liquid3)3Displacement is carried out to release HNO3Further improve the HNO in the flue gas before entering the absorption tower 73The concentration of the gas further forms regenerated acid containing nitric acid with higher concentration in the absorption tower 7, thereby avoiding excessive nitrate from entering the reaction furnace 1 to be roasted to generate NOxThe recovery rate of nitric acid is influenced, and the operation cost is further reduced.
The transportation of the pyrolysis-generated metal oxide, the pre-concentration and the subsequent treatment of the flue gas from the absorption tower 7 in this example are the same as in the fourth example. The reaction principle of this example is the same as that of the example.
EXAMPLE six
As shown in fig. 3, the embodiment provides a stainless steel mixed acid waste liquid regenerated acid device, which includes a reaction furnace 1, an absorption tower 7, a nitric acid displacement tower 19 and a preconcentrator 3, where the nitric acid displacement tower 19 and the preconcentrator 3 are of an integrated structure, the nitric acid displacement tower 19 is located above the preconcentrator 3, the mixed acid waste liquid inlet pipe is communicated with a mixed acid waste liquid inlet of the preconcentrator 3, a mixed acid waste liquid outlet of the preconcentrator 3 is communicated with a mixed acid waste liquid inlet at the top of the nitric acid displacement tower 19, a flue gas inlet of the preconcentrator 3 is communicated with a flue gas outlet of the reaction furnace 1, a concentrated liquid outlet of the preconcentrator 3 is communicated with a concentrated liquid inlet of the reaction furnace 1, and a flue gas outlet of the nitric acid displacement tower 19 is communicated with a flue gas inlet of the absorption tower 7; the top of the absorption tower 7 is communicated with a spray header, and the bottom of the absorption tower 7 is communicated with a regenerated acid outlet pipe. In the stainless steel mixed acid waste liquid regenerated acid equipment provided by the embodiment, the nitric acid replacement tower 19 is additionally arranged between the preconcentrator 3 and the absorption tower 7 of the preconcentrator 3, and is used for pre-absorbing HF gas regenerated by the partial reaction furnace 1, and simultaneously utilizing pre-absorbed hydrofluoric acid to react Fe (NO) in the mixed acid waste liquid3)3Displacement is carried out to release HNO3Further improve the HNO in the flue gas before entering the absorption tower 73The concentration of the gas; meanwhile, the nitric acid displacement tower 19 and the preconcentrator 3 are of an integrated structure, the integration level of the whole equipment is high, and the occupied area is saved. The flue gas in the preconcentrator 3 enters a nitric acid displacement tower 19, and the mixed acid waste liquid in the nitric acid displacement tower 19 enters the preconcentrator3 in (b).
Further, a nitric acid displacement tower flow regulating valve 20 is arranged on a pipeline which is communicated with the mixed acid waste liquid outlet of the preconcentrator 3 and the mixed acid waste liquid inlet at the top of the nitric acid displacement tower 19. The flow of the mixed acid waste liquid sprayed into the nitric acid displacement tower 19 is adjusted by the flow adjusting valve 20 of the nitric acid displacement tower and the flow adjusting valve 6 of the mixed acid waste liquid.
The transportation of the pyrolysis-generated metal oxide, the pre-concentration and the subsequent treatment of the flue gas from the absorption tower 7 in this example are the same as in the fourth example. The reaction principle of this example is the same as that of the example.
EXAMPLE seven
As shown in fig. 4, the embodiment provides a stainless steel mixed acid waste liquid regenerated acid device, which includes a reaction furnace 1, an absorption tower 7, a nitric acid displacement tower 19 and a preconcentrator 3, where the nitric acid displacement tower 19 and the preconcentrator 3 are of an integrated structure, the nitric acid displacement tower 19 is located above the preconcentrator 3, the mixed acid waste liquid inlet pipe is communicated with a mixed acid waste liquid inlet at the top of the nitric acid displacement tower 19, a flue gas inlet of the preconcentrator 3 is communicated with a flue gas outlet of the reaction furnace 1, a concentrated liquid outlet of the preconcentrator 3 is communicated with a concentrated liquid inlet of the reaction furnace 1, and a flue gas outlet of the nitric acid displacement tower 19 is communicated with a flue gas inlet of the absorption tower 7; the top of the absorption tower 7 is communicated with a spray header, and the bottom of the absorption tower 7 is communicated with a regenerated acid outlet pipe. In the stainless steel mixed acid waste liquid regenerated acid equipment provided by the embodiment, the nitric acid replacement tower 19 is additionally arranged between the preconcentrator 3 and the absorption tower 7 of the preconcentrator 3, and the pre-absorbed hydrofluoric acid is utilized to treat Fe (NO) in the mixed acid waste liquid3)3Displacement to release HNO3The recovery rate of the nitric acid is improved; meanwhile, the nitric acid displacement tower 19 and the preconcentrator 3 are of an integrated structure, the integration level of the whole equipment is high, and the occupied area is saved. The flue gas in the preconcentrator 3 enters a nitric acid displacement tower 19, and the mixed acid waste liquid in the nitric acid displacement tower 19 enters the preconcentrator 3.
Further, the mixed acid waste liquid outlet of the preconcentrator 3 is communicated with the mixed acid waste liquid inlet at the top of the nitric acid displacement tower 19, and a nitric acid displacement tower flow regulating valve 20 is arranged on a pipeline communicated with the mixed acid waste liquid outlet and the nitric acid displacement tower 19. The flow of the mixed acid waste liquid sprayed into the nitric acid displacement tower 19 is adjusted by the flow adjusting valve 20 of the nitric acid displacement tower and the flow adjusting valve 6 of the mixed acid waste liquid.
The transportation of the pyrolysis-generated metal oxide, the pre-concentration and the subsequent treatment of the flue gas from the absorption tower 7 in this example are the same as in the fourth example. The reaction principle of this example is the same as that of the example.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (8)
1. A stainless steel mixed acid waste liquid regenerated acid process is characterized in that:
the mixed acid waste liquid enters a pre-concentration displacement device for pre-concentration treatment and displacement reaction; HF gas in high-temperature flue gas generated by the reaction furnace is absorbed by water to form hydrofluoric acid, and the hydrofluoric acid and metal nitrate in the mixed acid waste liquid are subjected to a displacement reaction to generate nitric acid and fluoride; directly contacting the mixed acid waste liquid with high-temperature flue gas generated by high-temperature decomposition in a reaction furnace for heat exchange, evaporating hydrofluoric acid and nitric acid in the mixed acid waste liquid into the high-temperature flue gas to obtain a concentrated solution of the mixed acid waste liquid, and washing and separating solid particles in the high-temperature flue gas; the concentrated solution of the mixed acid waste liquid enters a reaction furnace for pyrolysis;
the high-temperature flue gas after dust separation enters an absorption tower, and HF gas and HNO in the high-temperature flue gas are leached by spraying water3The gas is absorbed by the water to form a regenerated acid.
2. The stainless steel mixed acid waste liquid regenerated acid process as claimed in claim 1, characterized in that: the mixed acid waste liquid enters a nitric acid displacement tower of a pre-concentration displacement device in a spraying mode, HF gas in high-temperature flue gas from a pre-concentrator of the pre-concentration displacement device is absorbed by water to form hydrofluoric acid, the hydrofluoric acid and metal nitrate in the mixed acid waste liquid are subjected to displacement reaction, generated nitric acid and fluoride salt enter the mixed acid waste liquid, then the mixed acid waste liquid enters the pre-concentrator of the pre-concentration displacement device in a spraying mode and directly contacts with high-temperature flue gas generated in a reaction furnace to carry out heat exchange, nitric acid in the mixed acid waste liquid is evaporated into the high-temperature flue gas to obtain concentrated liquid of the mixed acid waste liquid, and meanwhile solid particles in the high-temperature flue gas are washed and separated; and the concentrated solution of the mixed acid waste liquid enters a reaction furnace for pyrolysis.
3. The stainless steel mixed acid waste liquid regenerated acid process as claimed in claim 1, characterized in that: the mixed acid waste liquid enters a preconcentrator of a preconcentration displacement device in a spraying mode and directly contacts with high-temperature flue gas generated in a reaction furnace for heat exchange, nitric acid in the mixed acid waste liquid is evaporated into the high-temperature flue gas, and a concentrated solution of the mixed acid waste liquid is obtained; then the high-temperature flue gas enters a nitric acid displacement tower of the pre-concentration displacement device and is washed by the sprayed mixed acid waste liquid, HF gas in the high-temperature flue gas is absorbed by water to form hydrofluoric acid, the hydrofluoric acid and metal nitrate in the mixed acid waste liquid are subjected to displacement reaction, the generated nitric acid and fluoride salt enter the mixed acid waste liquid, and then the nitric acid and fluoride salt return to a pre-concentrator for pre-concentration treatment.
4. The stainless steel mixed acid waste liquid regenerated acid process as claimed in any one of claims 2 to 3, characterized in that: the inlet flue gas temperature of the nitric acid displacement tower is 85-95 ℃, and the outlet flue gas temperature is 65-85 ℃.
5. The stainless steel mixed acid waste liquid regenerated acid process as claimed in claim 1, characterized in that: the high-temperature flue gas generated by pyrolysis in the reaction furnace contains water vapor, HF gas and HNO3Gas, NOxA gas.
6. The stainless steel mixed acid waste liquid regenerated acid process as claimed in claim 1, characterized in that: and solid powder generated in the reaction furnace is conveyed into an oxide bin for storage through an oxide conveying device connected with the bottom of the reaction furnace.
7. The stainless steel mixed acid waste liquid regenerated acid process as claimed in claim 1, characterized in that: flue gas from the absorption tower gets into venturi dust remover and sprays washing purification, and reentrant spray cooling tower sprays cooling and cools down, and the flue gas after the cooling gets into oxidation treatment in the oxidation tower, and reentrant denitration reactor carries out denitration treatment, and the atmosphere of discharging after up to standard.
8. The stainless steel mixed acid waste liquid regenerated acid process as claimed in claim 1, characterized in that: the temperature of the high-temperature flue gas generated in the reaction furnace is 200-300 ℃.
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| PCT/CN2019/106442 WO2020108028A1 (en) | 2018-11-30 | 2019-09-18 | Process for regenerating acid from stainless steel mixed acid waste liquid |
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| CN109467065B (en) * | 2018-11-30 | 2023-09-19 | 中冶南方工程技术有限公司 | Stainless steel mixed acid waste liquid regenerated acid equipment |
| CN109553152B (en) * | 2018-11-30 | 2021-09-10 | 中冶南方工程技术有限公司 | Stainless steel mixed acid waste liquid regenerated acid process |
| CN111960392B (en) * | 2020-08-12 | 2022-04-08 | 中冶南方工程技术有限公司 | Mixed acid waste liquid resource recovery system and process |
| CN112359366B (en) * | 2020-10-10 | 2021-11-23 | 东南大学 | Two-stage roasting regeneration device and method for waste mixed acid |
| CN113774213A (en) * | 2021-08-16 | 2021-12-10 | 中冶南方工程技术有限公司 | Recycling method and system of stainless steel mixed acid pickling sludge |
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| CN109553152A (en) | 2019-04-02 |
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