WO2020108029A1 - 一种不锈钢混酸废液再生酸设备 - Google Patents

一种不锈钢混酸废液再生酸设备 Download PDF

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Publication number
WO2020108029A1
WO2020108029A1 PCT/CN2019/106444 CN2019106444W WO2020108029A1 WO 2020108029 A1 WO2020108029 A1 WO 2020108029A1 CN 2019106444 W CN2019106444 W CN 2019106444W WO 2020108029 A1 WO2020108029 A1 WO 2020108029A1
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Prior art keywords
waste liquid
acid
tower
mixed acid
flue gas
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PCT/CN2019/106444
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English (en)
French (fr)
Inventor
赵金标
王军
丁煜
高俊峰
吴宗应
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中冶南方工程技术有限公司
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Publication of WO2020108029A1 publication Critical patent/WO2020108029A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00—Nitrogen; Compounds thereof
    • C01B21/20—Nitrogen oxides; Oxyacids of nitrogen; Salts thereof
    • C01B21/38—Nitric acid

Definitions

  • the invention belongs to the technical field of regeneration of mixed acid waste liquid, and in particular relates to a device for regenerating acid in stainless steel mixed acid waste liquid.
  • Fe+HNO 3 Fe(NO 3 ) 3 +NO+2H 2 O
  • FeO+4HNO 3 2Fe(NO 3 ) 3 +2H 2 O+NO 2
  • Fe(NO 3 ) 3 +3HF FeF 3 +3HNO 3
  • the mixed acid waste liquid after pickling contains a large amount of metal nitrate, metal fluoride, and incompletely reacted nitric acid and hydrofluoric acid.
  • the spray roasting method (or fluidized bed method) is often used to regenerate stainless steel waste mixed acid waste liquid.
  • the regeneration process is to provide gas and combustion air to the reaction furnace, and to provide combustion heat source to the reaction furnace through combustion.
  • the concentrated mixed acid waste The liquid is injected into the reaction furnace, and the following decomposition reactions occur in the high-temperature furnace:
  • HNO 3 aqueous solution
  • HNO 3 gas
  • the waste liquid sprayed into the reaction furnace is mainly metal nitrate and fluoride salt. Nitrate is decomposed into NO x during the roasting process of the reaction furnace. The flue gas containing NO x is cooled and cooled, and then part of the HNO 3 is recovered by oxidation in the oxidation tower. The conversion of NO x to nitric acid requires lower temperature and low conversion efficiency. The recovery rate of nitric acid is low.
  • the flue gas needs to be heated, is converted to N 2, not only need to consume a large amount of cooling water and gas, the need to consume a large amount of denitration agent (ammonia or urea), running cost increases in the denitration reactor.
  • denitration agent ammonia or urea
  • the object of the present invention is to provide a stainless steel mixed acid waste liquid regeneration acid equipment, which can effectively improve the recovery rate of nitric acid, and at the same time reduce the denitrification agent ammonia or urea consumption.
  • the technical solution of the present invention is a stainless acid mixed acid waste liquid regeneration acid equipment, including a reactor, an absorption tower, and preconcentration for hydrofluoric acid and nitrate replacement reaction and pre-concentration treatment of mixed acid waste liquid Displacement device;
  • the mixed acid waste liquid inlet of the pre-concentration replacement device communicates with the mixed acid waste liquid inlet pipe
  • the concentrated liquid outlet of the pre-concentration replacement device communicates with the concentrated liquid inlet of the reaction furnace
  • the flue gas of the reaction furnace The outlet is in communication with the flue gas inlet of the pre-concentration replacement device
  • the flue gas outlet of the pre-concentration replacement device is in communication with the flue gas inlet of the absorption tower
  • the top of the absorption tower is in communication with the spray water pipe, the absorption The bottom of the tower communicates with the regenerated acid outlet pipe.
  • the pre-concentration replacement device includes a nitric acid replacement tower and a pre-concentrator
  • the flue gas inlet of the pre-concentrator communicates with the flue gas outlet of the reaction furnace
  • the concentrated liquid outlet of the pre-concentrator is connected to the The concentrated liquid inlet of the reaction furnace is communicated
  • the flue gas outlet of the nitric acid replacement tower is communicated with the flue gas inlet of the absorption tower.
  • the bottom of the pre-concentrator communicates with the spray liquid pipe at the top of the pre-concentrator through a pre-concentrator circulation pump, and the spray end of the spray liquid pipe is located in the flue gas of the pre-concentrator Below the entrance.
  • the nitric acid replacement tower and the pre-concentrator are of a split structure, and the mixed acid waste liquid inlet pipe communicates with the mixed acid waste liquid inlet at the top of the nitric acid replacement tower; the mixed acid of the nitric acid replacement tower
  • the waste liquid outlet communicates with the mixed acid waste liquid inlet of the preconcentrator, and the flue gas outlet of the preconcentrator communicates with the flue gas inlet of the nitric acid replacement tower.
  • the nitric acid replacement tower and the pre-concentrator have an integrated structure, and the nitric acid replacement tower is located above the pre-concentrator.
  • the mixed acid waste liquid inlet pipe communicates with the mixed acid waste liquid inlet of the preconcentrator, and the mixed acid waste liquid outlet of the preconcentrator communicates with the mixed acid waste liquid inlet at the top of the nitric acid replacement tower.
  • the mixed acid waste liquid inlet pipe communicates with the mixed acid waste liquid inlet at the top of the nitric acid replacement tower.
  • the mixed acid waste liquid outlet of the preconcentrator is in communication with the mixed acid waste liquid inlet at the top of the nitric acid replacement tower.
  • the bottom of the reaction furnace is connected with an oxide conveying device.
  • the flue gas outlet of the absorption tower is sequentially connected with a venturi dust collector, a spray cooling tower, an oxidation tower and a denitration reactor.
  • the stainless steel mixed acid waste liquid regeneration acid equipment provided by the present invention performs pre-concentration treatment and nitric acid replacement reaction in the pre-concentration replacement device, and releases more HNO 3 in the pre-concentration replacement device, improving the recovery rate of nitric acid ;
  • the stainless steel mixed acid waste liquid regeneration acid equipment provided by the present invention realizes the substitution reaction between hydrofluoric acid and metal nitrate in the mixed acid waste liquid through the addition of a nitric acid replacement tower to generate nitric acid and fluoride salt, to avoid metal nitrate roasting It is decomposed into NO x in the furnace, which increases the load of the denitration device, increases the denitration agent and energy consumption, and reduces the operating cost.
  • FIG. 1 is a schematic diagram of an acid regeneration equipment for stainless steel mixed acid waste liquid provided by Embodiment 4 of the present invention
  • FIG. 2 is a schematic diagram of the acid regeneration equipment for stainless steel mixed acid waste liquid provided by Embodiment 5 of the present invention.
  • FIG. 3 is a schematic diagram of the acid regeneration equipment for stainless steel mixed acid waste liquid provided by Embodiment 6 of the present invention.
  • FIG. 4 is a schematic diagram of the acid regeneration equipment for stainless steel mixed acid waste liquid provided by Embodiment 7 of the present invention.
  • an embodiment of the present invention provides a stainless steel mixed acid waste liquid regeneration acid process.
  • the mixed acid waste liquid enters a pre-concentration replacement device for pre-concentration treatment and nitric acid replacement reaction;
  • HF gas in high-temperature flue gas is Water absorbs to form hydrofluoric acid, which reacts with the metal nitrate in the mixed acid waste liquid to generate nitric acid and fluoride salt;
  • the mixed acid waste liquid directly contacts the high-temperature flue gas generated by the high-temperature decomposition in the reactor 1 for heat exchange
  • the hydrofluoric acid and nitric acid in the mixed acid waste liquid are evaporated into the high temperature flue gas, and the concentrated liquid of the mixed acid waste liquid is obtained, and the solid particles in the high temperature flue gas are washed and separated;
  • the concentrated liquid of the mixed acid waste liquid then enters the reaction furnace High-temperature decomposition in 1;
  • the high-temperature flue gas after dust separation enters the absorption tower 7, and after being sprayed
  • the stainless steel mixed acid waste liquid regeneration acid process releases more HNO 3 in the pre-concentration replacement device and improves the recovery rate of nitric acid; instead of decomposing the metal nitrate into NO x in the roaster, and then passing Subsequent cooling reduces the temperature, and oxidizes and recovers part of HNO 3 through the oxidation tower 14, thereby reducing the generation of NO x in the system, which in turn reduces the load of the denitration device, reduces the consumption of denitration agent and energy consumption, and reduces the operating cost.
  • the high-temperature flue gas leaving the top of the reaction furnace 1 enters the pre-concentration replacement device.
  • the mixed acid waste liquid enters the pre-concentration replacement device through the mixed acid waste liquid flow regulating valve 6.
  • the mixed acid waste liquid in the pre-concentration replacement device is circulated by the pre-concentrator
  • the pump 4 is ejected and sprayed through the top of the pre-concentrator 3 to form a circuit.
  • HF gas is absorbed by water to form hydrofluoric acid, and the hydrofluoric acid and metal nitrate in the mixed acid waste liquid undergo replacement reaction to generate nitric acid and fluoride salt; high-temperature reaction furnace 1 gas and pre-concentration sprayed
  • the mixed acid waste liquid of the replacement device is directly contacted for heat exchange. Due to the evaporation of part of nitric acid and hydrofluoric acid, the circulating acid liquid is concentrated; meanwhile, the residual solid oxide particles in the gas are washed with the mixed acid waste liquid to generate Fe(NO 3 ) 3 Part of the nitric acid in the mixed acid waste liquid is evaporated into the flue gas during heat exchange with the high-temperature flue gas.
  • the gas After cooling and separating the dust, the gas enters the absorption tower 7, and is sprayed with water, and the gas is sent from the bottom of the absorption tower 7. During the countercurrent process, the HF gas and HNO 3 gas in the flue gas are absorbed by water to form regenerated acid.
  • HNO 3 gas
  • HNO 3 aqueous solution
  • the high-temperature flue gas generated by pyrolysis in the reaction furnace 1 contains water vapor, HF gas, HNO 3 gas, and NO x gas.
  • the concentrated mixed acid waste liquid is injected into the reaction furnace 1 through the reaction furnace feed pump 5, A decomposition reaction occurs in a high-temperature furnace.
  • the temperature of the high-temperature flue gas generated in the reaction furnace is 200-300°C.
  • the high-temperature flue gas enters a pre-concentration replacement device to exchange heat with the mixed acid waste liquid, so that the nitric acid in the mixed acid waste liquid evaporates into the flue gas.
  • the metal oxide solid powder whose main component generated by pyrolysis is Fe 2 O 3 is sent to the oxide bin for storage through the oxide conveying device 2 connected to the bottom of the reaction furnace 1.
  • the flue gas from the absorption tower 7 enters the venturi dust collector 8 for spray washing and purification, and then enters the spray cooling tower 10 for spray cooling to cool down, and the cooled flue gas enters the oxidation tower 14 for oxidation Treatment, and then enter the denitration reactor 17 for denitration treatment, and discharged into the atmosphere after reaching the standard.
  • the flue gas from the absorption tower 7 contains combustion exhaust gas and steam exhaust gas contaminated with trace acids and NO x . It passes through the venturi dust collector 8 and is washed and purified by the circulating spray liquid from the venturi dust collector circulation pump 9 to reduce Metal oxide dust and acid content; the flue gas then enters the spray cooling tower 10, and the spray cooling liquid sprayed by the spray cooling tower circulating pump 12 is used to cool and cool the spray.
  • the heat of the circulating spray liquid is sprayed by the spray cooling tower
  • the heat exchanger 11 is brought out by indirect heat exchange with external cooling water; the exhaust gas after cooling down is drawn into the oxidation tower 14 through the exhaust fan 13 for oxidation, and the following reaction takes place in the oxidation tower 14 to generate part of nitric acid:
  • the generated nitric acid is sprayed and absorbed by the circulating spray liquid from the oxidation tower circulation pump 16, and the excess reaction heat and absorption heat are taken out by the oxidation tower heat exchanger 15 through indirect heat exchange with external cooling water;
  • the flue gas after the oxidation reaction enters the denitration reactor 17, and is sprayed with a denitration agent (ammonia water or urea) for denitration treatment.
  • a denitration agent ammonia water or urea
  • the exhaust gas after denitrification treatment reaches the standard is discharged into the atmosphere through the chimney 18.
  • an embodiment of the present invention provides a stainless steel mixed acid waste liquid regeneration acid process.
  • the mixed acid waste liquid enters the nitric acid replacement tower 19 of the pre-concentration replacement device by spraying, so that the HF gas in the high-temperature flue gas It is absorbed by water to form hydrofluoric acid. Hydrofluoric acid and metal nitrate in the mixed acid waste liquid have a replacement reaction.
  • the generated nitric acid and fluoride salt enter the mixed acid waste liquid, and then the mixed acid waste liquid enters the pre-concentration replacement device by spraying.
  • the preconcentrator 3 is in direct contact with the high-temperature flue gas generated in the reactor 1 for heat exchange.
  • the nitric acid in the mixed acid waste liquid is evaporated into the high-temperature flue gas, and the concentrated liquid of the mixed acid waste liquid is obtained.
  • the solid particles are washed and separated; the concentrated liquid of mixed acid waste liquid enters the reactor 1 for high-temperature decomposition; the high-temperature flue gas after separating the dust enters the absorption tower 7, and after washing by water spray, the HF gas in the high-temperature flue gas, HNO 3 gas is absorbed by water to form regenerated acid.
  • the stainless steel mixed acid waste liquid regeneration acid process adds a nitric acid replacement tower 19 between the pre-concentrator 3 and the pre-concentrator 3 and the absorption tower 7 for pre-absorbing the HF gas regenerated in the partial reactor 1 while using the pre
  • the absorbed hydrofluoric acid replaces Fe(NO 3 ) 3 in the mixed acid waste liquid, releasing HNO 3 , further increasing the concentration of HNO 3 gas in the flue gas before entering the absorption tower 7, and further forming a high content in the absorption tower 7.
  • the heating medium gas denitration agent ammonia or urea
  • the mixed acid waste liquid is input into the nitric acid replacement tower 19 through the mixed acid waste liquid flow control valve 6 and sprayed from the top for pre-absorption of part of HF gas and replacement of HNO 3.
  • the nitric acid replacement tower 19 may be a hollow tower or with a Packed absorption tower 7.
  • the flow rate injected into the nitric acid replacement tower 19 can be adjusted appropriately according to the situation of the mixed acid waste liquid to ensure the smooth progress of the hydrofluoric acid and nitrate replacement reaction.
  • the high-temperature flue gas generated by the reaction furnace 1 leaves 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, and is pumped out by the pre-concentrator circulation pump 4.
  • the preconcentrator 3 is sprayed into the top to form a loop.
  • the gas in the high-temperature reactor 1 is in direct contact with the circulating spray liquid of the preconcentrator 3 for heat exchange.
  • the evaporation of part of the acid liquid makes the circulating acid liquid concentrated; meanwhile, the circulating acid liquid is used to wash the remaining oxide solid particles in the gas to generate Fe (NO 3 ) 3 ; Part of the nitric acid in the mixed acid waste liquid is evaporated into the flue gas during heat exchange with the high-temperature flue gas.
  • the newly added nitric acid replacement tower 19 can be installed independently of the pre-concentrator 3 and connected through the flue gas pipeline; it can also be combined with the pre-concentrator 3 and placed above the pre-concentrator 3.
  • the reactions occurring in the nitric acid replacement tower 19 and the preconcentrator 3 are the same as those in the preconcentration replacement device in Embodiment 1, and the principles are the same.
  • the mixed acid waste liquid passes through a branch pipe connected to the outlet pipe of the preconcentrator circulation pump 4 to the nitric acid replacement tower 19,
  • the branch pipe is provided with a nitric acid displacement tower flow regulating valve 20, and the mixed acid waste liquid enters the nitric acid displacement tower 19 by spraying to perform a displacement reaction.
  • the flow rate injected into the nitric acid replacement tower 19 can be adjusted by the mixed acid waste liquid flow control valve 6 and the nitric acid replacement tower flow control valve 20 according to the mixed acid waste liquid condition to ensure the smooth progress of the hydrofluoric acid and nitrate replacement reaction.
  • the inlet flue gas temperature of the nitric acid displacement tower 19 is 85°C to 95°C, and the outlet flue gas temperature is 65 to 85°C.
  • the treatment method and principle of the flue gas from the absorption tower 7 in this embodiment are the same as those in the first embodiment.
  • the mixed acid waste liquid enters the pre-concentrator 3 of the pre-concentration replacement device by spraying and directly contacts the high-temperature flue gas generated in the reaction furnace 1 for heat exchange, and the nitric acid in the mixed acid waste liquid is evaporated to In the high temperature flue gas, the concentrated liquid of the mixed acid waste liquid is obtained, and at the same time, the solid particles in the high temperature flue gas are washed and separated; the concentrated liquid of the mixed acid waste liquid enters the reaction furnace 1 for high temperature decomposition; then the high temperature flue gas enters the pre-concentration and replacement The nitric acid replacement tower 19 of the device is washed by the sprayed mixed acid waste liquid.
  • the HF gas in the high-temperature flue gas is absorbed by water to form hydrofluoric acid.
  • the hydrofluoric acid and the metal nitrate in the mixed acid waste liquid undergo a replacement reaction.
  • the fluoride salt enters the mixed acid waste liquid, and then returns to the pre-concentrator 3 for pre-concentration treatment.
  • the stainless steel mixed acid waste liquid regeneration acid process adds a nitric acid replacement tower 19 between the pre-concentrator 3 and the pre-concentrator 3 and the absorption tower 7 for pre-absorbing the HF gas regenerated in the partial reactor 1 while using the pre
  • the absorbed hydrofluoric acid replaces Fe(NO 3 ) 3 in the mixed acid waste liquid, releasing HNO 3 , avoiding excessive nitrate from entering the reactor 1 and roasting to produce NO x , which affects the recovery rate of nitric acid.
  • the high-temperature flue gas generated by the reaction furnace 1 leaves the top of the reaction furnace 1 and enters the pre-concentrator 3, and the mixed acid waste liquid directly enters the pre-concentrator 3 through the mixed acid waste liquid flow regulating valve 6, and is pumped by the pre-concentrator circulation pump 4 Strike out and spray through the top of the pre-concentrator 3 to form a loop.
  • the gas in the high-temperature reactor 1 is in direct contact with the circulating spray liquid of the preconcentrator 3 for heat exchange.
  • the evaporation of part of the acid liquid makes the circulating acid liquid concentrated; meanwhile, the circulating acid liquid is used to wash the remaining oxide solid particles in the gas to generate Fe (NO 3 ) 3 ; Part of HNO 3 (nitric acid) in the mixed acid waste liquid is evaporated into the flue gas during heat exchange with high-temperature flue gas.
  • the mixed acid waste liquid in the pre-concentrator 3 is connected to the nitric acid replacement tower 19 from the outlet pipe of the pre-concentrator circulation pump 4 at the bottom of the pre-concentrator 3, and the branch pipe is provided with a nitric acid replacement tower flow regulating valve 20.
  • the mixed acid waste liquid is injected from the top to pre-absorb part of the HF gas and replace nitric acid.
  • the nitric acid replacement tower 19 may be a hollow tower or an absorption tower 7 with packing.
  • the newly added nitric acid replacement tower 19 can be installed independently of the pre-concentrator 3 and connected through the flue gas pipeline; it can also be combined with the pre-concentrator 3 and placed above the pre-concentrator 3.
  • the reactions occurring in the nitric acid replacement tower 19 and the preconcentrator 3 are the same as those in the preconcentration replacement device in Embodiment 1, and the principles are the same.
  • the inlet flue gas temperature of the nitric acid displacement tower 19 is 85°C to 95°C, and the outlet flue gas temperature is 65 to 85°C.
  • the flow rate injected into the nitric acid replacement tower 19 can be adjusted appropriately according to the situation of the mixed acid waste liquid through the nitric acid replacement tower flow control valve 20 to ensure the smooth progress of the hydrofluoric acid and nitrate replacement reaction.
  • the treatment method and principle of the flue gas from the absorption tower 7 in this embodiment are the same as those in the first embodiment.
  • this embodiment provides a stainless steel mixed acid waste liquid regeneration acid equipment, including a reactor 1, an absorption tower 7, and a hydrofluoric acid and nitrate replacement reaction and pre-concentration for the mixed acid waste liquid Pre-concentration replacement device for treatment; the mixed acid waste liquid inlet of the pre-concentration replacement device is connected to the mixed acid waste liquid inlet pipe, and the concentrated liquid outlet of the pre-concentration replacement device is connected to the concentrated liquid inlet of the reaction furnace 1,
  • the flue gas outlet of the reaction furnace 1 communicates with the flue gas inlet of the pre-concentration replacement device, and the flue gas outlet of the pre-concentration replacement device communicates with the flue gas inlet of the absorption tower 7;
  • the spray water pipe communicates, and the bottom of the absorption tower 7 communicates with the regenerated acid outlet pipe.
  • the stainless steel mixed acid waste liquid regeneration acid equipment performs pre-concentration treatment and nitric acid replacement reaction in the pre-concentration replacement device, releases more HNO 3 in the pre-concentration replacement device, and improves the recovery rate of nitric acid; Fluoric acid and metal nitrate in the mixed acid waste liquid undergo substitution reaction to generate nitric acid and fluoride salt, to avoid the decomposition of metal nitrate into NO x in the roaster, increase the load of the denitration device and increase the denitration agent and energy consumption, reducing the operation cost.
  • the pre-concentration replacement device includes a nitric acid replacement tower 19 and a pre-concentrator 3, the flue gas inlet of the pre-concentrator 3 communicates with the flue gas outlet of the reaction furnace 1, the concentration of the pre-concentrator 3 The liquid outlet communicates with the concentrated liquid inlet of the reaction furnace 1, and the flue gas outlet of the nitric acid replacement tower 19 communicates with the flue gas inlet of the absorption tower 7.
  • the bottom of the pre-concentrator 3 communicates with the spray liquid pipe on the top of the pre-concentrator 3 through a pre-concentrator circulation pump 4, and the spray end of the spray liquid pipe is located in the pre-concentrator 3 Below the flue gas inlet, the mixed acid waste liquid is fully in direct contact with the high temperature flue gas for heat exchange, and the nitric acid and hydrofluoric acid in the mixed acid waste liquid are more evaporated into the high temperature flue gas.
  • the main component produced by pyrolysis is the metal oxide of Fe 2 O 3 , which is sent to the oxide silo for storage through the oxide conveying device 2 at the bottom of the reaction furnace 1.
  • a mixed acid waste liquid flow control valve 6 is provided on the mixed acid waste liquid inlet pipe, and the mixed acid waste liquid flow rate injected into the nitric acid replacement tower 19 is adjusted by the mixed acid waste liquid flow adjustment valve 6 to ensure the replacement of hydrofluoric acid and nitrate The reaction went smoothly.
  • the flue gas outlet of the absorption tower 7 is connected with a venturi dust collector 8, a spray cooling tower 10, an oxidation tower 14 and a denitration reactor 17 in order, and the flue gas is denitrified to discharge after reaching the standard.
  • the flue gas outlet of the absorption tower 7 communicates with the flue gas inlet of the venturi dust collector 8, and the liquid outlet at the bottom of the venturi dust collector 8 passes through the venturi dust collector circulation pump 9 and the venturi
  • the spray liquid pipe at the top of the dust collector 8 is connected, and the spray end of the spray liquid pipe is located below the flue gas inlet of the venturi dust collector 8, and the flue gas outlet of the venturi dust collector 8 communicates with the flue gas inlet .
  • the circulating liquid in the Venturi dust collector 8 enters the top of the Venturi dust collector 8 in a spraying manner through the Venturi dust collector circulation pump 9 and directly contacts with the flue gas from the flue gas inlet of the Venturi dust collector 8 to spray Dust is sprayed to remove solid particles in the flue gas, and the flue gas that has passed the dust enters the spray cooling tower 10.
  • the liquid outlet of the spray cooling tower 10 communicates with the spray liquid pipe at the top of the spray cooling tower 10 through the circulation pipe of the spray cooling tower 10, and the spray end of the spray liquid pipe is located in the spray cooling Below the flue gas inlet of the tower 10, the flue gas outlet of the spray cooling tower 10 communicates with the flue gas inlet of the oxidation tower 14.
  • a spray cooling tower circulating pump 12 and a spray cooling tower heat exchanger 11 are provided on the circulation pipe of the spray cooling tower 10, and the cooling water of the spray cooling tower heat exchanger 11 is used for top-in and bottom-out.
  • the circulating liquid in the spray cooling tower 10 is drawn out through the venturi dust collector circulation pump 9 and then passes through the heat exchange of the spray cooling tower heat exchanger 11 and then enters the top of the spray cooling tower 10 in a spraying manner.
  • the flue gas from the flue gas inlet of the cooling tower 10 directly contacts to perform spray cooling, and the cooled flue gas enters the oxidation tower 14.
  • the outlet of the oxidation tower 14 is connected to the spray liquid pipe at the top of the oxidation tower 14 through the circulation pipe of the oxidation tower 14, and the spray end of the spray liquid pipe is located above the flue gas inlet of the oxidation tower 14
  • the flue gas outlet of the oxidation tower 14 communicates with the flue gas inlet of the denitration reactor 17.
  • An oxidation tower circulation pump 16 and an oxidation tower heat exchanger 15 are provided on the circulation pipe of the oxidation tower 14, and the cooling water of the oxidation tower heat exchanger 15 adopts top-down and top-out.
  • the circulating liquid in the oxidation tower 14 is drawn through the venturi dust collector circulation pump 9 and then passes through the heat exchange of the oxidation tower heat exchanger 15 and then enters the top of the oxidation tower 14 by spraying and enters the flue gas inlet of the oxidation tower 14
  • the flue gas is directly contacted, spray cooling is performed, and the cooled flue gas enters the denitration reactor 17 for denitration.
  • the flue gas outlet of the denitration reactor 17 communicates with the chimney 18, and the denitration reactor 17 is provided with a denitration agent inlet; the flue gas entering the denitration reactor 17 reacts with the denitration agent (ammonia or urea) to generate nitrogen Water and flue gas meeting the standard are discharged into the atmosphere through the chimney 18.
  • the denitration agent ammonia or urea
  • this embodiment provides a stainless steel mixed acid waste liquid regeneration acid equipment, including a reaction furnace 1, an absorption tower 7, a nitric acid replacement tower 19, and a preconcentrator 3, the nitric acid replacement tower 19, and the preconcentrator 3 is a split structure, the mixed acid waste liquid inlet pipe communicates with the mixed acid waste liquid inlet at the top of the nitric acid replacement tower 19; the mixed acid waste liquid outlet of the nitric acid replacement tower 19 and the mixed acid waste liquid of the preconcentrator 3 The inlet is connected, the flue gas outlet of the pre-concentrator 3 communicates with the flue gas inlet of the nitric acid replacement tower 19; the flue gas inlet of the pre-concentrator 3 communicates with the flue gas outlet of the reaction furnace 1, The concentrated liquid outlet of the preconcentrator 3 communicates with the concentrated liquid inlet of the reaction furnace 1, the flue gas outlet of the nitric acid replacement tower 19 communicates with the flue gas inlet of the absorption tower 7; the top of the absorption tower
  • the stainless acid mixed acid waste liquid regeneration acid equipment provided in this embodiment adds a nitric acid replacement tower 19 between the pre-concentrator 3 and the pre-concentrator 3 and the absorption tower 7 for pre-absorbing the HF gas regenerated in the reaction furnace 1 while using the pre
  • the absorbed hydrofluoric acid replaces Fe(NO 3 ) 3 in the mixed acid waste liquid, releasing HNO 3 , further increasing the concentration of HNO 3 gas in the flue gas before entering the absorption tower 7, and further forming a high content in the absorption tower 7.
  • regenerated acid concentration of nitric acid, nitrates avoid excessive firing into a furnace NO x production affect the recovery of nitric acid, further reduces the operating costs.
  • this embodiment provides a stainless steel mixed acid waste liquid regeneration acid equipment, including a reaction furnace 1, an absorption tower 7, a nitric acid replacement tower 19, and a preconcentrator 3, the nitric acid replacement tower 19, and the preconcentrator 3 is an integrated structure, the nitric acid replacement tower 19 is located above the preconcentrator 3, the mixed acid waste liquid inlet pipe is connected to the mixed acid waste liquid inlet of the preconcentrator 3, the preconcentrator 3
  • the mixed acid waste liquid outlet communicates with the mixed acid waste liquid inlet at the top of the nitric acid replacement tower 19, the flue gas inlet of the preconcentrator 3 communicates with the flue gas outlet of the reaction furnace 1, and the concentrated liquid of the preconcentrator 3
  • the outlet is connected to the concentrated liquid inlet of the reaction furnace 1, the flue gas outlet of the nitric acid replacement tower 19 is connected to the flue gas inlet of the absorption tower 7; the top of the absorption tower 7 is connected to the spray water pipe, The bottom of the absorption tower 7 communicates with the re
  • the stainless acid mixed acid waste liquid regeneration acid equipment adds a nitric acid replacement tower 19 between the pre-concentrator 3 and the pre-concentrator 3 and the absorption tower 7 for pre-absorbing the HF gas regenerated in the reaction furnace 1 while using the pre
  • the absorbed hydrofluoric acid replaces Fe(NO 3 ) 3 in the mixed acid waste liquid, releasing HNO 3 , further increasing the concentration of HNO 3 gas in the flue gas before entering the absorption tower 7; at the same time, the nitric acid replacement tower 19 and the preconcentrator 3 It is a one-piece structure, with high integration of the whole equipment, saving floor space.
  • the flue gas in the preconcentrator 3 enters the nitric acid replacement tower 19, and the mixed acid waste liquid in the nitric acid replacement tower 19 enters the preconcentrator 3.
  • a pipe connecting the mixed acid waste liquid outlet of the preconcentrator 3 and the mixed acid waste liquid inlet at the top of the nitric acid replacement tower 19 is provided with a nitric acid replacement tower flow regulating valve 20.
  • the flow rate of the mixed acid waste liquid sprayed into the nitric acid replacement tower 19 is adjusted by the flow control valve 20 of the nitric acid replacement tower and the mixed acid flow control valve 6 of the mixed acid.
  • this embodiment provides a stainless steel mixed acid waste liquid regeneration acid equipment, including a reaction furnace 1, an absorption tower 7, a nitric acid replacement tower 19, and a preconcentrator 3, the nitric acid replacement tower 19, and the preconcentrator 3 is an integrated structure, the nitric acid replacement tower 19 is located above the preconcentrator 3, the mixed acid waste liquid inlet pipe communicates with the mixed acid waste liquid inlet at the top of the nitric acid replacement tower 19, the preconcentrator 3
  • the flue gas inlet of the reactor is connected to the flue gas outlet of the reaction furnace 1, the concentrated liquid outlet of the preconcentrator 3 is connected to the concentrated liquid inlet of the reaction furnace 1, the flue gas outlet of the nitric acid replacement tower 19 is connected to the The flue gas inlet of the absorption tower 7 communicates; the top of the absorption tower 7 communicates with the spray water pipe, and the bottom of the absorption tower 7 communicates with the regenerated acid outlet pipe.
  • the stainless steel mixed acid waste liquid regeneration acid equipment provided in this embodiment adds a nitric acid replacement tower 19 between the preconcentrator 3 and the preconcentrator 3 between the absorption tower 7 and uses pre-absorbed hydrofluoric acid to remove Fe(NO 3 in the mixed acid waste liquid ) 3 Perform replacement to release HNO 3 to improve the recovery rate of nitric acid; at the same time, the nitric acid replacement tower 19 and the pre-concentrator 3 are of an integrated structure, and the entire equipment is highly integrated, saving floor space.
  • the flue gas in the preconcentrator 3 enters the nitric acid replacement tower 19, and the mixed acid waste liquid in the nitric acid replacement tower 19 enters the preconcentrator 3.
  • the mixed acid waste liquid outlet of the pre-concentrator 3 is communicated with the mixed acid waste liquid inlet at the top of the nitric acid replacement tower 19, and the pipeline connecting the two is provided with a nitric acid replacement tower flow regulating valve 20.
  • the flow rate of the mixed acid waste liquid sprayed into the nitric acid replacement tower 19 is adjusted by the flow control valve 20 of the nitric acid replacement tower and the mixed acid flow control valve 6 of the mixed acid.

Abstract

一种不锈钢混酸废液再生酸设备，包括反应炉（1）、吸收塔（7）以及用于对混酸废液进行氢氟酸和硝酸盐置换反应以及预浓缩处理的预浓缩置换装置。该不锈钢混酸废液再生酸设备提高了硝酸的回收率，减少了NO x的产生，降低了运行费用。

Description

一种不锈钢混酸废液再生酸设备 技术领域
本发明属于混酸废液再生技术领域，具体涉及一种不锈钢混酸废液再生酸设备。
背景技术
钢铁、机械加工行业一般采用硝酸和氢氟酸的混合液对不锈钢进行“化学酸洗”，以去除其氧化铁皮和贫铬层，一般基体金属、贫铬层及金属氧化物溶解时发生下列反应：
Fe+HNO 3＝Fe(NO 3) 3+NO+2H 2O
Fe(NO 3) 3+3HF→FeF 3+3HNO 3
Fe 2O 3+6HNO 3＝2Fe(NO 3) 3+3H 2O
FeO+4HNO 3＝2Fe(NO 3) 3+2H 2O+NO 2
Fe 3O 4+10HNO 3＝3Fe(NO 3) 3+5H 2O+NO 2
Fe(NO 3) 3+3HF＝FeF 3+3HNO 3
Me xO y+HNO 3→Me(NO 3) z+H 2O
Me xO y+HF→MeF z+H 2O
……
(Me指除铁外的其他金属元素)
酸洗之后的混酸废液含有大量金属硝酸盐、金属氟化盐以及未完全反应的硝酸、氢氟酸。目前常采用喷雾焙烧法(或流化床法)对不锈钢废混酸废液进行再生，其再生工艺是通过向反应炉提供燃气和助燃空气，通过燃烧向反应炉提供燃烧热源，浓缩后的混酸废液喷入反应炉中，在高温的炉内发生下列分解反应：
H 2O(液)＝H 2O(气)
HNO 3(水溶液)＝HNO 3(气)；硝酸蒸发
HF(水溶液)＝HF(气)；氢氟酸蒸发
2FeF 3+3H 2O＝Fe 2O 3+6HF
2Fe(NO 3) 3+3H 2O＝Fe 2O 3+6HNO 3；
MeF x+H 2O→Me yO z+HF；氟化物分解
Me(NO 3) x+H 2O→Me yO z+HNO 3；硝酸盐分解
2HNO 3(气)＝NO 2(气)+H 2O(气)+O 2(气)；硝酸分解
NO 2＝NO+1/2O 2
……
(Me指除铁外的其他金属元素)
反应炉气体由水蒸气、HF、NO x气体及燃烧废气组成，从反应炉顶部离开进入到预浓缩器，混酸废液由预浓缩器的底部打出后从顶部喷入，形成回路。在预浓缩器中，高温反应炉气体与预浓缩器循环喷淋液直接接触进行热交换，混酸废液液中的部分HNO 3(硝酸)在与高温烟气热交换中被蒸发到烟气中，部分酸液的蒸发使得循环酸液得以浓缩。含有硝酸气体的烟气经过分离粉尘后进入吸收塔中被水吸收形成再生酸。
采用这一工艺，由于混酸废液直接进入预浓缩器浓缩，部分游离硝酸在预浓缩器中蒸发，喷入反应炉中的废液主要为金属硝酸盐及氟化盐。硝酸盐在反应炉焙烧过程中分解为NO x，含有NO x的烟气经过冷却降温，再通过氧化塔氧化回收部分HNO 3，将NO x转化为硝酸需要较低的温度，且转化效率低，硝酸的回收率低。而未回收的NO x，需要对烟气进行加热，在脱硝反应器中转化为N 2，不但需要消耗大量冷却水和燃气，还需消耗大量的脱硝剂(氨水或尿素)，增加运行成本。
发明内容
为了克服上述现有技术存在的不足，本发明的目的是提供一种不锈钢混酸废液再生酸设备，能够有效提高硝酸的回收率，同时降低脱硝剂氨水或尿素消耗。
为实现上述目的，本发明的技术方案为一种不锈钢混酸废液再生酸设备，包括反应炉、吸收塔以及用于对混酸废液进行氢氟酸和硝酸盐置换反应以及预浓缩处理的预浓缩置换装置；所述预浓缩置换装置的混酸废液进口与混酸废液进管连通，所述预浓缩置换装置的浓缩液出口与所述反应炉的浓缩液进口连通，所述反应炉的烟气出口与所述预浓缩置换装置的烟气入口连通，所述预浓缩置换装置的烟气出口与所述吸收塔的烟气入口连通；所述吸收塔的顶部与喷淋水管连通，所述吸收塔的底部与再生酸出管连通。
进一步地，所述预浓缩置换装置包括硝酸置换塔和预浓缩器，所述预浓缩器的烟气入口与所述反应炉的烟气出口连通，所述预浓缩器的浓缩液出口与所述反应炉的浓缩液进口连通，所述硝酸置换塔的烟气出口与所述吸收塔的烟气入口连通。
进一步地，所述预浓缩器的底部通过预浓缩器循环泵与所述预浓缩器顶部的喷淋液管连通，且所述喷淋液管的喷淋端位于所述预浓缩器的烟气入口的下方。
作为一种实施方式，所述硝酸置换塔和所述预浓缩器为分体式结构，所述混酸废液进管与所述硝酸置换塔顶部的混酸废液进口连通；所述硝酸置换塔的混酸废液出口与所述预浓缩器的混酸废液进口连通，所述预浓缩器的烟气出口与所述硝酸置换塔的烟气入口连通。
作为一种实施方式，所述硝酸置换塔和所述预浓缩器为一体式结构，所述硝酸置换塔位于所述预浓缩器的上方。
进一步地，所述混酸废液进管与所述预浓缩器的混酸废液进口连通，所述预浓缩器的混酸废液出口与所述硝酸置换塔顶部的混酸废液进口连通。
进一步地，所述混酸废液进管与所述硝酸置换塔顶部的混酸废液进口连通。
更进一步地，所述预浓缩器的混酸废液出口与所述硝酸置换塔顶部的混酸废液进口连通。
进一步地，所述反应炉的底部与氧化物输送装置连接。
进一步地，所述吸收塔的烟气出口依次连接有文丘里除尘器、喷淋冷却塔、氧化塔和脱硝反应器。
与现有技术相比，本发明的有益效果：
(1)本发明的提供的不锈钢混酸废液再生酸设备在预浓缩置换装置中进行预浓缩处理以及硝酸置换反应，在预浓缩置换装置中释放出更多的HNO 3，提高了硝酸的回收率；
(2)本发明的提供的不锈钢混酸废液再生酸设备通过增加的硝酸置换塔实现氢氟酸与混酸废液中的金属硝酸盐发生置换反应生成硝酸和氟化盐，避免金属硝酸盐在焙烧炉内分解为NO x，增加脱硝装置的负荷以及增加脱硝剂以及能源消耗，降低了运行费用。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其它的附图。
图1为本发明实施例四提供的不锈钢混酸废液再生酸设备的示意图；
图2为本发明实施例五提供的不锈钢混酸废液再生酸设备的示意图；
图3为本发明实施例六提供的不锈钢混酸废液再生酸设备的示意图；
图4为本发明实施例七提供的不锈钢混酸废液再生酸设备的示意图；
图中：1、反应炉，2、氧化物输送装置，3、预浓缩器，4、第一预浓缩器 循环泵，5、第二预浓缩器循环泵，6、混酸废液流量调节阀，7、吸收塔，8、文丘里除尘器，9、文丘里除尘器循环泵，10、喷淋冷却塔，11、喷淋冷却塔换热器，12、喷淋冷却塔循环泵，13、废气风机，14、氧化塔，15、氧化塔换热器，16、氧化塔循环泵，17、脱硝反应器，18、烟囱，19、硝酸置换塔，20、硝酸置换塔流量调节阀。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其它实施例，都属于本发明保护的范围。
实施例一
如图1-图4所示，本发明实施例提供一种不锈钢混酸废液再生酸工艺，混酸废液进入预浓缩置换装置中进行预浓缩处理以及硝酸置换反应；高温烟气中的HF气体被水吸收形成氢氟酸，氢氟酸与混酸废液中的金属硝酸盐发生置换反应，生成硝酸和氟化盐；混酸废液与反应炉1中高温分解产生的高温烟气直接接触进行热交换，混酸废液中的氢氟酸和硝酸被蒸发到高温烟气中，并得到混酸废液的浓缩液，同时高温烟气中的固体颗粒被洗涤分离；混酸废液的浓缩液再进入反应炉1中进行高温分解；分离粉尘后的高温烟气进入到吸收塔7，经喷水淋洗，高温烟气中的HF气体、HNO 3气体被水吸收形成再生酸。本实施例提供的不锈钢混酸废液再生酸工艺在预浓缩置换装置中释放出更多的HNO 3，提高了硝酸的回收率；而不是使金属硝酸盐在焙烧炉内分解为NO x，再通过后续的冷却降温，通过氧化塔14氧化回收部分HNO 3，从而减少了系统中NO x的产生，继而减少了脱硝装置的负荷，减少了脱硝剂的消耗以及能源消耗，降低了运行 费用。
从反应炉1顶部离开的高温烟气进入到预浓缩置换装置，混酸废液通过混酸废液流量调节阀6进入器预浓缩置换装置中，预浓缩置换装置中的混酸废液由预浓缩器循环泵4打出经预浓缩器3顶部喷入，形成回路。在预浓缩置换装置中，HF气体被水吸收形成氢氟酸，氢氟酸与混酸废液中的金属硝酸盐发生置换反应，生成硝酸和氟化盐；高温反应炉1气体与喷入预浓缩置换装置的混酸废液直接接触进行热交换，由于部分硝酸和氢氟酸的蒸发使得循环酸液得以浓缩；同时利用混酸废液洗涤气体中残留的氧化物固体颗粒，生成Fe(NO 3) 3，而混酸废液液中的部分硝酸在与高温烟气热交换中被蒸发到烟气中。
在预浓缩置换装置中，发生如下反应：
HF(气)→HF(水溶液)；氢氟酸吸收
Fe(NO 3) 3+3HF→FeF 3+3HNO 3；硝酸置换
HNO 3(水溶液)→HNO 3(气)；硝酸蒸发
Fe 2O 3+6HNO 3→2Fe(NO 3) 3+3H 2O；(烟气中的金属氧化物被溶解)
Me xO y+HNO 3→Me(NO 3) z+H 2O
冷却和分离粉尘后的气体进入到吸收塔7，经喷水淋洗，气体从吸收塔7底部送入，在逆流过程中，烟气中HF气体、HNO 3气体被水吸收形成再生酸。
HNO 3(气)→HNO 3(水溶液)；硝酸部分吸收
HF(气)→HF(水溶液)；氢氟酸吸收
进一步地，所述反应炉1中高温分解产生的高温烟气中含有水蒸气、HF气体、HNO 3气体、NO x气体。如图2-图4所示，通过向反应炉1提供燃气和助燃空气，通过燃烧向反应炉1提供燃烧热源，浓缩后的混酸废液通过反应炉供料泵5喷入反应炉1中，在高温的炉内发生分解反应。反应炉中产生的高温烟气的温度为200～300℃，高温烟气进入预浓缩置换装置与混酸废液进行热交换，使混酸废液中的硝酸蒸发到烟气中。
进一步地，高温分解产生的主要成分为Fe 2O 3的金属氧化物固体粉末，通过 与反应炉1底部连接的氧化物输送装置2送入氧化物仓储存。
进一步地，从吸收塔7出来的烟气进入文丘里除尘器8进行喷淋洗涤净化，再进入喷淋冷却塔10进行进行喷淋冷却降温，降温后的烟气后进入氧化塔14中进行氧化处理，再进入脱硝反应器17进行脱硝处理，达标后排入大气。
从吸收塔7出来的烟气含有燃烧尾气和被微量酸、NO x污染的水蒸汽尾气经过文丘里除尘器8，通过文丘里除尘器循环泵9打出的循环喷淋液进行洗涤净化，降低其中的金属氧化物粉尘及酸含量；随后烟气进入喷淋冷却塔10，通过喷淋冷却塔循环泵12打出的循环喷淋液进行喷淋冷却降温，循环喷淋液的热量由喷淋冷却塔换热器11经过和外置冷却水间接换热而带出；经过降温后的尾气通过废气风机13抽入氧化塔14中进行氧化，在氧化塔14中发生如下反应生成部分硝酸：
NO 2+H 2O＝2HNO 3+NO
NO+1/2O 2＝NO 2
生成的硝酸由氧化塔循环泵16打出的循环喷淋液进行喷淋吸收，多余的反应热和吸收热由氧化塔换热器15经过和外置冷却水间接换热而带出；
然后氧化反应后的烟气进入脱硝反应器17，经喷入脱硝剂(氨水或尿素)，进行脱硝处理，化学反应如下：
NO+NO 2+2NH 3＝2N 2+3H 2O
4NO+4NH 3+O 2＝4N 2+6H 2O
2NO 2+4NH 3+O 2＝4N 2+6H 2O
经过脱硝处理达标的尾气经烟囱18排入大气。
实施例二
如图2和图4所示，本发明实施例提供一种不锈钢混酸废液再生酸工艺，混酸废液以喷淋的方式进入预浓缩置换装置的硝酸置换塔19，使高温烟气中HF气体被水吸收形成氢氟酸，氢氟酸与混酸废液中的金属硝酸盐发生置换反应，生成的硝酸和氟化盐进入混酸废液，然后混酸废液以喷淋的方式进入预浓缩置换装置的预浓缩器3并与反应炉1中产生的高温烟气直接接触进行热交换，混 酸废液中的硝酸被蒸发到高温烟气中，并得到混酸废液的浓缩液，同时高温烟气中的固体颗粒被洗涤分离；混酸废液的浓缩液再进入反应炉1中进行高温分解；分离粉尘后的高温烟气进入到吸收塔7，经喷水淋洗，高温烟气中的HF气体、HNO 3气体被水吸收形成再生酸。本实施例提供的不锈钢混酸废液再生酸工艺在预浓缩器3在预浓缩器3于吸收塔7之间增加硝酸置换塔19，用于预吸收部分反应炉1再生的HF气体，同时利用预吸收的氢氟酸对混酸废液中Fe(NO 3) 3进行置换，释放出HNO 3，进一步提高进入吸收塔7前烟气中HNO 3气体的浓度，在吸收塔7中进一步形成含较高浓度硝酸的再生酸，避免过多的硝酸盐进入反应炉1内焙烧产生NO x影响硝酸回收率，进一步降低后续喷淋冷却塔10和氧化塔14的NO x浓度，降低氧化塔14的工作负荷，进一步降低冷却循环水的耗量，降低进入到脱硝反应器17中未回收的NO x浓度，进一步降低脱硝剂(氨水或尿素)消耗量和加热介质所需的燃气消耗量，进而降低了运行成本。
本实施例中混酸废液通过混酸废液流量调节阀6输入硝酸置换塔19，从顶部喷入，用于预吸收部分HF气体和置换出HNO 3，硝酸置换塔19可以是中空塔或带有填料的吸收塔7。喷入硝酸置换塔19的流量可根据混酸废液的情况做适度调节，以保证氢氟酸和硝酸盐置换反应的顺利进行。同时反应炉1产生的高温烟气从反应炉1顶部离开进入到预浓缩器3，混酸废液通过混酸废液流量调节阀6直接进入预浓缩器3，并由预浓缩器循环泵4打出经预浓缩器3顶部喷入，形成回路。高温反应炉1气体与预浓缩器3循环喷淋液直接接触进行热交换，由于部分酸液的蒸发使得循环酸液得以浓缩；同时利用循环酸液洗涤气体中残留的氧化物固体颗粒，生成Fe(NO 3) 3；混酸废液液中的部分硝酸在与高温烟气热交换中被蒸发到烟气中。
新增的硝酸置换塔19可以独立于预浓缩器3设置，通过烟气管道连接；也可以和预浓缩器3合并设置，放置在预浓缩器3上方。本实施例中在硝酸置换塔19和预浓缩器3中发生反应于实施例一中预浓缩置换装置中发生反应一样，原理一样。
作为一种实现方式，如图4所示，生成的硝酸和氟化盐进入混酸废液后，混酸废液由预浓缩器循环泵4出口管路接出的一根支管到硝酸置换塔19，该支管上设有硝酸置换塔流量调节阀20，混酸废液以喷淋的方式进入硝酸置换塔19，进行置换反应。喷入硝酸置换塔19的流量可通过混酸废液流量调节阀6和硝酸置换塔流量调节阀20根据混酸废液的情况共同调节，以保证氢氟酸和硝酸盐置换反应的顺利进行。
进一步地，为保证预吸收、置换及蒸发的顺利进行，所述硝酸置换塔19的进口烟气温度为85℃～95℃，出口烟气温度为65～85℃。
本实施例中经过吸收塔7出来的烟气的处理方法以及原理均与实施例一中相同。
实施例三
如图3所示，混酸废液以喷淋的方式进入预浓缩置换装置的预浓缩器3并与反应炉1中产生的高温烟气直接接触进行热交换，混酸废液中的硝酸被蒸发到高温烟气中，并得到混酸废液的浓缩液，同时高温烟气中的固体颗粒被洗涤分离；混酸废液的浓缩液再进入反应炉1中进行高温分解；然后高温烟气进入预浓缩置换装置的硝酸置换塔19，被喷淋的混酸废液洗涤，高温烟气中HF气体被水吸收形成氢氟酸，氢氟酸与混酸废液中的金属硝酸盐发生置换反应，生成的硝酸和氟化盐进入混酸废液，然后回到预浓缩器3中进行预浓缩处理。本实施例提供的不锈钢混酸废液再生酸工艺在预浓缩器3在预浓缩器3于吸收塔7之间增加硝酸置换塔19，用于预吸收部分反应炉1再生的HF气体，同时利用预吸收的氢氟酸对混酸废液中Fe(NO 3) 3进行置换，释放出HNO 3，避免过多的硝酸盐进入反应炉1内焙烧产生NO x，影响硝酸回收率。
本实施例中反应炉1产生的高温烟气从反应炉1顶部离开进入到预浓缩器3，混酸废液通过混酸废液流量调节阀6直接进入预浓缩器3，并由预浓缩器循 环泵4打出经预浓缩器3顶部喷入，形成回路。高温反应炉1气体与预浓缩器3循环喷淋液直接接触进行热交换，由于部分酸液的蒸发使得循环酸液得以浓缩；同时利用循环酸液洗涤气体中残留的氧化物固体颗粒，生成Fe(NO 3) 3；混酸废液液中的部分HNO 3(硝酸)在与高温烟气热交换中被蒸发到烟气中。同时预浓缩器3中的混酸废液由预浓缩器3底部的预浓缩器循环泵4出口管路接出一根支管到硝酸置换塔19，该支管上设有硝酸置换塔流量调节阀20，混酸废液从顶部喷入，用于预吸收部分HF气体和置换出硝酸，硝酸置换塔19可以是中空塔或带有填料的吸收塔7。
新增的硝酸置换塔19可以独立于预浓缩器3设置，通过烟气管道连接；也可以和预浓缩器3合并设置，放置在预浓缩器3上方。本实施例中在硝酸置换塔19和预浓缩器3中发生反应于实施例一中预浓缩置换装置中发生反应一样，原理一样。
进一步地，为保证预吸收、置换及蒸发的顺利进行，所述硝酸置换塔19的进口烟气温度为85℃～95℃，出口烟气温度为65～85℃。喷入硝酸置换塔19的流量可通过硝酸置换塔流量调节阀20根据混酸废液的情况做适度调节，以保证氢氟酸和硝酸盐置换反应的顺利进行。
本实施例中经过吸收塔7出来的烟气的处理方法以及原理均与实施例一中相同。
实施例四
如图2-图4所示，本实施例提供一种不锈钢混酸废液再生酸设备，包括反应炉1、吸收塔7以及用于对混酸废液进行氢氟酸和硝酸盐置换反应以及预浓缩处理的预浓缩置换装置；所述预浓缩置换装置的混酸废液进口与混酸废液进管连通，所述预浓缩置换装置的浓缩液出口与所述反应炉1的浓缩液进口连通，所述反应炉1的烟气出口与所述预浓缩置换装置的烟气入口连通，所述预浓缩置换装置的烟气出口与所述吸收塔7的烟气入口连通；所述吸收塔7的顶部与 喷淋水管连通，所述吸收塔7的底部与再生酸出管连通。本发明的提供的不锈钢混酸废液再生酸设备在预浓缩置换装置中进行预浓缩处理以及硝酸置换反应，在预浓缩置换装置中释放出更多的HNO 3，提高了硝酸的回收率；同时氢氟酸与混酸废液中的金属硝酸盐发生置换反应生成硝酸和氟化盐，避免金属硝酸盐在焙烧炉内分解为NO x，增加脱硝装置的负荷以及增加脱硝剂以及能源消耗，降低了运行费用。
进一步地，所述预浓缩置换装置包括硝酸置换塔19和预浓缩器3，所述预浓缩器3的烟气入口与所述反应炉1的烟气出口连通，所述预浓缩器3的浓缩液出口与所述反应炉1的浓缩液进口连通，所述硝酸置换塔19的烟气出口与所述吸收塔7的烟气入口连通。
进一步地，所述预浓缩器3的底部通过预浓缩器循环泵4与所述预浓缩器3顶部的喷淋液管连通，且所述喷淋液管的喷淋端位于所述预浓缩器3的烟气入口的下方，使混酸废液充分与高温烟气直接接触进行热交换，混酸废液中的硝酸和氢氟酸更多的被蒸发到高温烟气中。
进一步地，所述反应炉1的底部与氧化物输送装置2连接。高温分解产生的主要成分为Fe 2O 3的金属氧化物，通过反应炉1底部的氧化物输送装置2送入氧化物仓储存。
本实施例中混酸废液进管上设有混酸废液流量调节阀6，通过混酸废液流量调节阀6调节喷入硝酸置换塔19的混酸废液流量，以保证氢氟酸和硝酸盐置换反应的顺利进行。
进一步地，所述吸收塔7的烟气出口依次连接有文丘里除尘器8、喷淋冷却塔10、氧化塔14和脱硝反应器17，对烟气脱硝至达标后排放。
作为一种实现方式，所述吸收塔7的烟气出口与文丘里除尘器8的烟气进 口连通，文丘里除尘器8底部的出液口通过文丘里除尘器循环泵9与所述文丘里除尘器8顶部的喷淋液管连通，且喷淋液管的喷淋端位于文丘里除尘器8的烟气进口的下方，所述文丘里除尘器8的烟气出口与的烟气进口连通。文丘里除尘器8内的循环液通过文丘里除尘器循环泵9以喷淋的方式进入文丘里除尘器8的顶部，与文丘里除尘器8的烟气进口进来的烟气直接接触，进行喷淋除尘，除去烟气中的固体颗粒，经过除尘的烟气进入喷淋冷却塔10。
作为一种实现方式，喷淋冷却塔10的出液口通过喷淋冷却塔10循环管道与喷淋冷却塔10顶部的喷淋液管连通，且喷淋液管的喷淋端位于喷淋冷却塔10的烟气进口的下方，所述喷淋冷却塔10的烟气出口与氧化塔14的烟气进口连通。喷淋冷却塔10循环管道上设有喷淋冷却塔循环泵12和喷淋冷却塔换热器11，喷淋冷却塔换热器11的冷却水采用上进下出。喷淋冷却塔10内的循环液通过文丘里除尘器循环泵9抽出后经过喷淋冷却塔换热器11的换热，再以喷淋的方式进入喷淋冷却塔10的顶部，与喷淋冷却塔10的烟气进口进来的烟气直接接触，进行喷淋冷却，经过冷却的烟气进入氧化塔14。
作为一种实现方式，氧化塔14的出液口通过氧化塔14循环管道与氧化塔14顶部的喷淋液管连通，且喷淋液管的喷淋端位于氧化塔14的烟气进口的上方，所述氧化塔14的烟气出口与脱硝反应器17的烟气进口连通。氧化塔14循环管道上设有氧化塔循环泵16和氧化塔换热器15，氧化塔换热器15的冷却水采用上进下出。氧化塔14内的循环液通过文丘里除尘器循环泵9抽出后经过氧化塔换热器15的换热，再以喷淋的方式进入氧化塔14的顶部，与氧化塔14的烟气进口进来的烟气直接接触，进行喷淋冷却，经过冷却的烟气进入脱硝反应器17中脱硝。
作为一种实现方式，脱硝反应器17的烟气出口与烟囱18连通，脱硝反应 器17设有脱硝剂加入口；进入脱硝反应器17的烟气与脱硝剂(氨水或尿素)反应生成氮气和水，达标的烟气经烟囱18排入大气。
本实施例的反应原理与实施例一相同。
实施例五
如图2所示，本实施例提供一种不锈钢混酸废液再生酸设备，包括反应炉1、吸收塔7硝酸置换塔19和预浓缩器3，所述硝酸置换塔19和所述预浓缩器3为分体式结构，所述混酸废液进管与所述硝酸置换塔19顶部的混酸废液进口连通；所述硝酸置换塔19的混酸废液出口与所述预浓缩器3的混酸废液进口连通，所述预浓缩器3的烟气出口与所述硝酸置换塔19的烟气入口连通；所述预浓缩器3的烟气入口与所述反应炉1的烟气出口连通，所述预浓缩器3的浓缩液出口与所述反应炉1的浓缩液进口连通，所述硝酸置换塔19的烟气出口与所述吸收塔7的烟气入口连通；所述吸收塔7的顶部与喷淋水管连通，所述吸收塔7的底部与再生酸出管连通。本实施例提供的不锈钢混酸废液再生酸设备在预浓缩器3在预浓缩器3于吸收塔7之间增加硝酸置换塔19，用于预吸收部分反应炉1再生的HF气体，同时利用预吸收的氢氟酸对混酸废液中Fe(NO 3) 3进行置换，释放出HNO 3，进一步提高进入吸收塔7前烟气中HNO 3气体的浓度，在吸收塔7中进一步形成含较高浓度硝酸的再生酸，避免过多的硝酸盐进入反应炉1内焙烧产生NO x影响硝酸回收率，还进一步降低了运行成本。
本实施例的高温分解产生金属氧化物的输送、预浓缩以及从吸收塔7出来的烟气的后续处理均与实施例四相同。本实施例的反应原理与实施例二相同。
实施例六
如图3所示，本实施例提供一种不锈钢混酸废液再生酸设备，包括反应炉1、吸收塔7硝酸置换塔19和预浓缩器3，所述硝酸置换塔19和所述预浓缩器3为一体式结构，所述硝酸置换塔19位于所述预浓缩器3的上方，所述混酸废液进管与所述预浓缩器3的混酸废液进口连通，所述预浓缩器3的混酸废液出口与 所述硝酸置换塔19顶部的混酸废液进口连通，所述预浓缩器3的烟气入口与所述反应炉1的烟气出口连通，所述预浓缩器3的浓缩液出口与所述反应炉1的浓缩液进口连通，所述硝酸置换塔19的烟气出口与所述吸收塔7的烟气入口连通；所述吸收塔7的顶部与喷淋水管连通，所述吸收塔7的底部与再生酸出管连通。本实施例提供的不锈钢混酸废液再生酸设备在预浓缩器3在预浓缩器3于吸收塔7之间增加硝酸置换塔19，用于预吸收部分反应炉1再生的HF气体，同时利用预吸收的氢氟酸对混酸废液中Fe(NO 3) 3进行置换，释放出HNO 3，进一步提高进入吸收塔7前烟气中HNO 3气体的浓度；同时硝酸置换塔19和预浓缩器3为一体式结构，整个设备的集成度高，节约占地面积。预浓缩器3中的烟气进入硝酸置换塔19中，硝酸置换塔19中的混酸废液进入预浓缩器3中。
进一步地，所述预浓缩器3的混酸废液出口与所述硝酸置换塔19顶部的混酸废液进口连通的管道上设有硝酸置换塔流量调节阀20。通过硝酸置换塔流量调节阀20和混酸废液流量调节阀6共同调节喷入硝酸置换塔19的混酸废液流量。
本实施例的高温分解产生金属氧化物的输送、预浓缩以及从吸收塔7出来的烟气的后续处理均与实施例四相同。本实施例的反应原理与实施例三相同。
实施例七
如图4所示，本实施例提供一种不锈钢混酸废液再生酸设备，包括反应炉1、吸收塔7硝酸置换塔19和预浓缩器3，所述硝酸置换塔19和所述预浓缩器3为一体式结构，所述硝酸置换塔19位于所述预浓缩器3的上方，所述混酸废液进管与所述硝酸置换塔19顶部的混酸废液进口连通，所述预浓缩器3的烟气入口与所述反应炉1的烟气出口连通，所述预浓缩器3的浓缩液出口与所述反应炉1的浓缩液进口连通，所述硝酸置换塔19的烟气出口与所述吸收塔7的烟气入口 连通；所述吸收塔7的顶部与喷淋水管连通，所述吸收塔7的底部与再生酸出管连通。本实施例提供的不锈钢混酸废液再生酸设备在预浓缩器3在预浓缩器3于吸收塔7之间增加硝酸置换塔19，利用预吸收的氢氟酸对混酸废液中Fe(NO 3) 3进行置换释放出HNO 3，提高硝酸的回收率；同时硝酸置换塔19和预浓缩器3为一体式结构，整个设备的集成度高，节约占地面积。预浓缩器3中的烟气进入硝酸置换塔19中，硝酸置换塔19中的混酸废液进入预浓缩器3中。
进一步地，所述预浓缩器3的混酸废液出口与所述硝酸置换塔19顶部的混酸废液进口连通，两者连通的管道上设有硝酸置换塔流量调节阀20。通过硝酸置换塔流量调节阀20和混酸废液流量调节阀6共同调节喷入硝酸置换塔19的混酸废液流量。
本实施例的高温分解产生金属氧化物的输送、预浓缩以及从吸收塔7出来的烟气的后续处理均与实施例四相同。本实施例的反应原理与实施例二相同。
以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (10)

  1. 一种不锈钢混酸废液再生酸设备，其特征在于：包括反应炉、吸收塔以及用于对混酸废液进行氢氟酸和硝酸盐置换反应以及预浓缩处理的预浓缩置换装置；所述预浓缩置换装置的混酸废液进口与混酸废液进管连通，所述预浓缩置换装置的浓缩液出口与所述反应炉的浓缩液进口连通，所述反应炉的烟气出口与所述预浓缩置换装置的烟气入口连通，所述预浓缩置换装置的烟气出口与所述吸收塔的烟气入口连通；所述吸收塔的顶部与喷淋水管连通，所述吸收塔的底部与再生酸出管连通。
  2. 如权利要求1所述的一种不锈钢混酸废液再生酸设备，其特征在于：所述预浓缩置换装置包括硝酸置换塔和预浓缩器，所述预浓缩器的烟气入口与所述反应炉的烟气出口连通，所述预浓缩器的浓缩液出口与所述反应炉的浓缩液进口连通，所述硝酸置换塔的烟气出口与所述吸收塔的烟气入口连通。
  3. 如权利要求2所述的一种不锈钢混酸废液再生酸设备，其特征在于：所述预浓缩器的底部通过预浓缩器循环泵与所述预浓缩器顶部的喷淋液管连通，且所述喷淋液管的喷淋端位于所述预浓缩器的烟气入口的下方。
  4. 如权利要求2所述的一种不锈钢混酸废液再生酸设备，其特征在于：所述硝酸置换塔和所述预浓缩器为分体式结构，所述混酸废液进管与所述硝酸置换塔顶部的混酸废液进口连通；所述硝酸置换塔的混酸废液出口与所述预浓缩器的混酸废液进口连通，所述预浓缩器的烟气出口与所述硝酸置换塔的烟气入口连通。
  5. 如权利要求2所述的一种不锈钢混酸废液再生酸设备，其特征在于：所述硝酸置换塔和所述预浓缩器为一体式结构，所述硝酸置换塔位于所述预浓缩器的上方。
  6. 如权利要求5所述的一种不锈钢混酸废液再生酸设备，其特征在于：所述混 酸废液进管与所述预浓缩器的混酸废液进口连通，所述预浓缩器的混酸废液出口与所述硝酸置换塔顶部的混酸废液进口连通。
  7. 如权利要求5所述的一种不锈钢混酸废液再生酸设备，其特征在于：所述混酸废液进管与所述硝酸置换塔顶部的混酸废液进口连通。
  8. 如权利要求7所述的一种不锈钢混酸废液再生酸设备，其特征在于：所述预浓缩器的混酸废液出口与所述硝酸置换塔顶部的混酸废液进口连通。
  9. 如权利要求1所述的一种不锈钢混酸废液再生酸设备，其特征在于：所述反应炉的底部与氧化物输送装置连接。
  10. 如权利要求1所述的一种不锈钢混酸废液再生酸设备，其特征在于：所述吸收塔的烟气出口依次连接有文丘里除尘器、喷淋冷却塔、氧化塔和脱硝反应器。
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