WO2020124655A1 - 硫/硝酸盐铁-炭还原制备硫磺并回收脱硫/硝剂的工艺 - Google Patents

硫/硝酸盐铁-炭还原制备硫磺并回收脱硫/硝剂的工艺 Download PDF

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WO2020124655A1
WO2020124655A1 PCT/CN2018/124115 CN2018124115W WO2020124655A1 WO 2020124655 A1 WO2020124655 A1 WO 2020124655A1 CN 2018124115 W CN2018124115 W CN 2018124115W WO 2020124655 A1 WO2020124655 A1 WO 2020124655A1
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tower
reduction
outlet
separator
nitrate
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PCT/CN2018/124115
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French (fr)
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马春元
夏霄
崔琳
张立强
赵希强
李军
冯太
张世珍
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山东大学
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Priority to US16/618,937 priority Critical patent/US11292718B2/en
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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
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/02—Preparation of sulfur; Purification
    • C01B17/04—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides
    • C01B17/05—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides by wet processes
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/02—Preparation of sulfur; Purification
    • C01B17/04—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides
    • C01B17/0473—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides by reaction of sulfur dioxide or sulfur trioxide containing gases with reducing agents other than hydrogen sulfide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D1/00—Evaporating
    • B01D1/28—Evaporating with vapour compression
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/10—Filter screens essentially made of metal
    • B01D39/12—Filter screens essentially made of metal of wire gauze; of knitted wire; of expanded metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
    • B01D39/2068—Other inorganic materials, e.g. ceramics
    • 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
    • B01D53/48—Sulfur compounds
    • B01D53/50—Sulfur oxides
    • B01D53/501—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
    • 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
    • B01D53/48—Sulfur compounds
    • B01D53/50—Sulfur oxides
    • B01D53/501—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
    • B01D53/502—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound characterised by a specific solution or suspension
    • 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
    • B01D53/54—Nitrogen compounds
    • B01D53/56—Nitrogen oxides
    • 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
    • B01D53/75—Multi-step processes
    • 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
    • B01D53/80—Semi-solid phase processes, i.e. by using slurries
    • 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
    • B01D53/96—Regeneration, reactivation or recycling of reactants
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/02—Preparation of sulfur; Purification
    • C01B17/04—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides
    • C01B17/0473—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides by reaction of sulfur dioxide or sulfur trioxide containing gases with reducing agents other than hydrogen sulfide
    • C01B17/0482—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides by reaction of sulfur dioxide or sulfur trioxide containing gases with reducing agents other than hydrogen sulfide with carbon or solid carbonaceous materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/40—Alkaline earth metal or magnesium compounds
    • B01D2251/402—Alkaline earth metal or magnesium compounds of magnesium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/40—Alkaline earth metal or magnesium compounds
    • B01D2251/404—Alkaline earth metal or magnesium compounds of calcium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/60—Inorganic bases or salts
    • B01D2251/604—Hydroxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/30—Sulfur compounds
    • B01D2257/302—Sulfur oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/40—Nitrogen compounds
    • B01D2257/402—Dinitrogen oxide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/40—Nitrogen compounds
    • B01D2257/404—Nitrogen oxides other than dinitrogen oxide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/02—Other waste gases
    • B01D2258/0283—Flue gases
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/017—Combinations of electrostatic separation with other processes, not otherwise provided for
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/02—Plant or installations having external electricity supply
    • B03C3/16—Plant or installations having external electricity supply wet type
    • 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
    • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
    • Y02C20/00—Capture or disposal of greenhouse gases
    • Y02C20/10—Capture or disposal of greenhouse gases of nitrous oxide (N2O)

Definitions

  • the invention belongs to the field of resource utilization of pollutants, and in particular relates to a system and method for reducing sulfur (nitrate) iron-carbon to prepare sulfur and recovering desulfurization (nitrate) agent at the same time.
  • Ozone denitration technology is more adaptable to the increasingly strict environmental protection requirements than traditional flue gas desulfurization and denitrification processes SCR and SNCR.
  • the advanced oxidation technology using ozone not only has a good removal effect on NOx, but also has other harmful pollutants (such as heavy metals) in the flue gas. Mercury, etc.) also has a good removal effect.
  • Carrying out denitration processes such as oxidation absorption at low temperatures is beneficial to the energy recovery of the boiler and reduces the difficulty of project construction.
  • the existing mature wet desulfurization process in China is used to improve the desulfurization and denitrification.
  • NOx is oxidized into high-valence oxides, which are then absorbed by the lye, and the denitration efficiency is high, which can meet the ultra-low emission requirements.
  • nitrate is very soluble in water, and metal ions in nitrate are very harmful to the equipment, and the resulting denitration waste liquid is difficult to handle, causing secondary pollution.
  • sulfur has the lowest molecular weight and high unit value of all sulfur-containing products; storage and transportation costs are low; and sulfur can be used as a raw material for the production of most sulfur-containing products and has a wide range of uses.
  • my country is also a country with a shortage of sulfur resources.
  • the annual import and consumption of sulfur is among the highest in the world, and it has a high degree of external dependence.
  • sulfur has far greater market value and application value than sulfuric acid.
  • the object of the present invention is to provide a system and method for sulfur/nitrate iron-carbon reduction to prepare sulfur while recovering the desulfurization/nitration agent.
  • the system and method can not only alleviate the difficulty of handling sulphate (mainly calcium sulphate) and nitrate waste liquid produced by denitrification in China, at the same time, the waste solid and waste liquid are used in resources, and the desulfurizing agent and The denitration agent realizes the recycling of desulfurization agent and denitration agent, reduces the exploitation of mineral resources such as limestone, protects the ecological environment, and alleviates the current shortage of sulfur resources in China, and reduces the external dependence of sulfur resources.
  • sulphate mainly calcium sulphate
  • nitrate waste liquid produced by denitrification in China
  • the denitration agent realizes the recycling of desulfurization agent and denitration agent, reduces the exploitation of mineral resources such as limestone, protects the ecological environment, and alleviates the current shortage of sulfur resources in China, and reduce
  • the technical solutions of the present invention are:
  • Sulfur/nitrate iron-carbon reduction system for preparing sulfur and recovering desulfurization/nitration agent, including desulfurization tower, denitration tower, chimney, drying device, reduction roaster, first separator, second separator, carbon thermal reduction Tower, third separator, reheater, fine dust removal device, sulfur recovery device, sulfur storage bin, concentration device, pneumatic conveying device and nitrate analysis tower, wherein the flue gas inlet of the desulfurization tower is connected to the flue gas source
  • the flue gas outlet of the desulfurization tower is connected to the flue gas inlet of the denitration tower, the flue gas outlet of the denitration tower is connected to the inlet of the wet electrostatic precipitator, and the outlet of the wet electrostatic precipitator is connected to the inlet of the chimney;
  • the tower kettle of the desulfurization tower is connected to the inlet of the drying device, the outlet of the drying device is connected to the inlet of the sulfate warehouse, and the reduction roaster is connected to the iron powder source, carbon powder source and sulfate warehouse;
  • the tower kettle of the denitration tower is connected to the inlet of the concentration device, the outlet of the concentration device is connected to the inlet of the nitrate analysis tower through a pneumatic conveying device, and the gas outlet of the nitrate analysis tower is connected to the inlet of the charcoal reduction tower;
  • a first separator is connected to the outlet end of the reduction roaster, the solid outlet of the first separator communicates with the interior of the reduction roaster, the gas outlet of the first separator is connected to the inlet of the second separator, and the solid outlet end of the second separator There is a filter device connected;
  • the gas outlet of the second separator is connected to the inlet of the charcoal reduction tower, the outlet of the charcoal reduction tower is connected to the inlet of the third separator, and the gas outlet of the third separator is connected to the reheater.
  • the dust removal device, sulfur recovery device and sulfur storage bin are connected in sequence.
  • the solid outlet of the third separator is connected to the carbon thermal reduction tower
  • the calcination decomposition temperature of sulfate is between 1350°C-1400°C, but after adding iron-carbon material, the decomposition temperature of sulfate calcination is greatly reduced, the decomposition temperature is about 700°C-1100°C, the reduction of temperature not only reduces energy consumption, while the temperature decreases after the thermal reduction of SO 2 and char prepared sULFUR consistent optimal temperature, can greatly improve the conversion of the sulfur product.
  • Sulfate calcination the main components of which are solid metal oxides and high concentration SO 2 gas. Part of the SO 2 gas can directly undergo carbon-thermal reduction reaction with carbon powder in the fluidized bed roasting tower to generate sulfur element. The addition of iron powder aid for SO 2 reduction reaction, help to improve the conversion of SO 2. The remaining SO 2 gas flows out of the reduction roaster with the flow of calcined flue gas.
  • the elemental sulfur is gaseous at high temperature in the fluidized bed roasting tower, and the airflow flowing from the outlet of the fluidized bed roasting tower carries roasting slag.
  • the roasting slag includes incompletely roasted sulfates, metal oxides, and carbon powder.
  • the unsintered complete sulfate with the largest specific gravity is separated by the first separator, and then returned to the fluidized bed reduction roaster to continue to participate in the reaction; the metal oxide, carbon powder and reducing gas with the smaller specific gravity enter the second separator, the second The separator separates the metal oxide and carbon powder from the reducing gas and enters the filtering device.
  • the reducing gas carries a small amount of incompletely separated roasting slag from the second separator and enters the carbon thermal reduction tower.
  • the SO 2 in the reducing gas reacts with the carbon material to generate elemental sulfur vapor.
  • the reducing gas from the carbon thermal reduction tower carries the powdered carbon material into the third separator, and the separated carbon powder returns to the carbon thermal reduction tower, and the reducing gas enters the reheater to cool down.
  • This part of the energy released by the reducing gas can be combined On site specific situation, make full use of this part of the energy; the reducing gas after cooling enters the fine dust removal device to filter out a small amount of roasting slag that has not been separated by the previous two high-temperature separators; finally, the reducing gas enters the sulfur recovery device to recover sulfur and store it In the sulfur storage tank, the remaining spent gas is returned to the flue gas purification system of the large system.
  • the thermal stability of nitrate is poor. Oxygen is released during thermal decomposition.
  • the decomposition temperature is also different according to the activity of nitrate metal ions.
  • the nitrate solution formed by common ozone oxidation-wet denitration process such as sodium nitrate solution above 400 °C Decomposed into sodium oxide, N 2 , O 2 and NOx, the solid metal oxide produced by the decomposition can be recycled as a denitration agent, the concentrated gas product is sent to the carbon thermal reduction tower in the presence of iron-carbon catalyst , Help to reduce the NOx reduction temperature, at the same time can improve the conversion rate of NOx.
  • the high-concentration SO 2 flue gas produced by sulfate calcination and the NOx produced by the thermal decomposition of nitrate can be directly reduced to elemental sulfur vapor and N 2 by reacting with iron-carbon materials at high temperature, and then successively subjected to dust removal, cooling, and fine dust removal After the process, sulfur is recovered by the sulfur recovery device, and metal oxides can replace limestone and other alkaline mineral resources as raw materials for the desulfurization (nitration) agent. This process can realize the recycling of desulfurization agent and denitration agent.
  • the filter device is provided with a chamber in the filter device, a filter screen is provided on the cross section of the chamber, a first outlet is provided at the upper end of the filter screen, and a second outlet is provided at the lower end of the filter screen.
  • the filtering device is provided with a cavity, and water is continuously fed into the cavity.
  • the water will dissolve the falling metal oxides to obtain an alkaline solution.
  • the alkaline solution flows out from the second outlet of the filtering device and is sent to the desulfurization tower for desulfurization.
  • the filter will not dissolve
  • the carbon powder of the water is intercepted, and the intercepted solid slurry flows out from the first outlet of the filtering device, after drying, it is sent to the fluidized bed reduction roaster to be burned.
  • a first dust collector is connected to the flue gas inlet of the desulfurization tower.
  • the first dust collector can remove the flue gas, reduce the content of solid particles in the flue gas, and help improve the working conditions in the desulfurization tower.
  • the flue between the first dust collector and the desulfurization tower is connected to an ozone generator.
  • the ozone generator passes ozone into the flue gas after dust removal, and ozone oxidizes NOx (mainly NO, about 95% by volume) in the flue gas into higher-order oxides of nitrogen, mainly NO 3 and N 2 O 5
  • NOx mainly NO, about 95% by volume
  • the SO 2 in the flue gas is oxidized to SO 3 , and then desulfurization and denitrification, the higher-order nitrogen oxides and sulfur trioxide in the flue gas react with the alkaline solution to produce nitrate and sulfate.
  • a second dust collector is connected between the denitration tower and the chimney.
  • the second dust collector can remove the flue gas again to ensure the cleanliness of the flue gas discharged into the atmosphere.
  • the first dust collector and the second dust collector are a bag dust collector, a cyclone separator, an axial separator or an electrostatic dust collector.
  • the concentration device includes a membrane concentration device and an MVR evaporation concentration device
  • the inlet of the membrane concentration device is connected to the tower kettle of the denitration tower
  • the outlet of the membrane concentration device is connected to the inlet of the MVR evaporation concentration device
  • the outlet of the MVR evaporation concentration device Install pneumatic conveying device.
  • Membrane concentrators and MVR evaporative concentrators concentrate the nitrate solution in two stages to ensure that the nitrate in the nitrate solution crystallizes into a powdery solid.
  • a feeder is provided between the drying device and the reduction roaster.
  • All fluidized bed roasters are: reduction roaster + charcoal reduction tower.
  • the carbon thermal reduction tower may be in various forms such as a fluidized bed, an air bed, and a bubbling bed;
  • the reduction roasting furnace can be in various forms such as air bed, fluidized bed, ebullated bed, rotary kiln and so on.
  • the feeder is a screw feeder or an air lock feeder.
  • the fine dust removal device is a metal mesh filter or a ceramic filter.
  • a process for preparing sulfur by sulfur/nitrate iron-carbon reduction and recovering desulfurization/nitration agent includes the following steps:
  • Flue gas is discharged after dust removal, ozone oxidation, alkali-eluting sulfur and alkali-eluting nitrate;
  • the sulfate precipitate produced in the desulfurization process is dried and then transported to the reduction roaster with carbon powder and iron powder according to the set ratio for roasting and reduction.
  • the roasting temperature is 800°C-1100°C and the roasting time is 4s-200s; required for reduction roasting
  • the heat is provided by the burner.
  • the burner fuel can be pulverized coal, natural gas, gasoline, diesel and other fuels.
  • the nitrate solution generated in the denitration process is concentrated and crystallized to produce nitrate powder.
  • the nitrate powder is decomposed into solid metal oxide and mixed gas at high temperature, and the mixed gas is sent to a reduction roaster to be reduced to nitrogen by roasting;
  • the unsintered complete sulfates separated by the first separator are returned to the reduction roaster to continue to participate in the reaction, and the metal oxide and carbon powder with a small specific gravity are separated by the second
  • the filter is separated and enters the filtering device.
  • the metal oxide is dissolved in the water in the filtering device to become an alkaline solution.
  • the carbon powder is intercepted by the filtering device, dried and reused;
  • the roasting gas After being condensed and dust-removed and sulfur recovered, the roasting gas enters the desulfurization tower and denitration tower for treatment, and is finally discharged.
  • the particle size of the sulfate salt transported to the reduction roaster is 60 ⁇ m-3 mm
  • the particle size of the nitrate salt is 60 ⁇ m-3 mm
  • the particle size of the carbon powder is 60 ⁇ m-3 mm
  • the particle size of the iron powder is 60 ⁇ m-500 ⁇ m.
  • the mass ratio of sulfate, carbon powder and iron powder in the reduction roaster is 8-11:1-2:1-2.
  • the high-temperature decomposition temperature of the nitrate powder is 400-600°C, and the reaction time is 10-200s.
  • the invention provides a process and device for preparing sulfur (nitrate) iron-carbon reduction to prepare sulfur and recovering desulfurization (nitrate) agent at the same time.
  • sulfur (nitrate) iron-carbon reduction to prepare sulfur and recovering desulfurization (nitrate) agent at the same time.
  • desulfurization (nitrate) agent at the same time.
  • Control the reaction temperature and reaction conditions respectively heat-treat the sulfate waste solid and nitrate waste liquid produced by wet desulfurization-ozone denitrification, and realize the recycling of the desulfurization (nitrate) agent while preparing the sulfur resource in the sulfur recovery solid waste
  • the reaction temperature and reaction conditions respectively heat-treat the sulfate waste solid and nitrate waste liquid produced by wet desulfurization-ozone denitrification, and realize the recycling of the desulfurization (nitrate) agent while preparing the sulfur resource in the sulfur recovery solid waste
  • FIG. 1 is a schematic structural view of a system for reducing sulfur (nitrate) iron-carbon to prepare sulfur while recovering desulfurization (nitrate) agent.
  • the first dust collector 1, the first dust collector, 2, the desulfurization tower, 3, the de-salting tower, 4, the second dust collector, 5, the chimney, 6, membrane concentration device, 7, MVR evaporation concentration device, 8, pneumatic conveying device, 9 , Nitrate analysis tower, 10, drying device, 11, iron powder silo, 12, sulfate silo, 13, carbon material silo, 14, reduction roaster, 15, first separator, 16, second separator, 17 ⁇ Filtration device, 18, charcoal heat reduction tower, 19, third separator, 20, reheater, 21, fine dust removal device, 22, sulfur recovery device, 23, sulfur storage bin.
  • a system for preparing sulfur by sulfur/nitrate iron-carbon reduction and recovering desulfurization/nitration agent includes a desulfurization tower 2, a denitration tower 3, a chimney 5, a drying device 10, a reduction roaster 14, a first Separator 15, second separator 16, charcoal thermal reduction tower 18, third separator 19, reheater 20, fine dust removal device 21, sulfur recovery device 22, sulfur storage bin 23, concentration device, pneumatic conveying device 8 and Nitrate analysis tower 9, wherein the flue gas inlet of the desulfurization tower 2 is connected to the flue gas source through the first dust collector 1, the flue gas outlet of the desulfurization tower 2 is connected to the flue gas inlet of the denitration tower 3, The flue gas outlet is connected to the chimney 5 through the second dust collector 4; the first dust collector 1 and the second dust collector 4 may be a bag dust collector, a cyclone separator, an axial separator or an electrostatic dust collector.
  • the tower kettle of the desulfurization tower 2 is connected to the inlet of the drying device 10, the outlet of the drying device 10 is connected to the sulfate warehouse 12 through the feeder, and the reduction roaster 14 is also connected to the iron powder warehouse 11, the carbon material warehouse 13 and the sulfate warehouse 12 ;
  • Feeder is screw feeder or air lock feeder.
  • a first separator 15 is connected to the outlet end of the reduction roaster 14, the solid outlet of the first separator 15 communicates with the interior of the reduction roaster 14, the gas outlet of the first separator 15 is connected to the inlet of the second separator 16, the second A filter device 17 is connected to the solid outlet end of the separator 16, the filter device 17 is provided with a chamber, a filter screen is provided on the cross section of the chamber, a first outlet is provided at the upper end of the filter screen, and a first outlet is provided at the lower end of the filter screen Second export;
  • the gas outlet of the second separator 16 is connected to the inlet of the charcoal reduction tower 18, the outlet of the charcoal reduction tower 18 is connected to the inlet of the third separator 19, and the gas outlet of the third separator 19 is connected to the reheater 20 ,
  • the reheater 20, the fine dust removal device 21, the sulfur recovery device 22 and the sulfur storage bin 23 are connected in sequence; the fine dust removal device 21 is a metal mesh filter or a ceramic filter.
  • the structure of the sulfur recovery device 22 is basically the same as the structure of the Claus process sulfur recovery device.
  • the solid outlet of the third separator is connected to the carbon thermal reduction tower 18.
  • the first separator 15 and the second separator 16 may be various types of separators such as a high-temperature cyclone separator and a high-temperature axial separator.
  • the heat exchange medium of the reheater 20 may be various types such as cooling water, air, thermal oil, and molten salt.
  • the inlet of the membrane concentration device 6 is connected to the tower kettle of the denitration tower 3, the outlet of the membrane concentration device 6 is connected to the inlet of the MVR evaporation concentration device 7, and the outlet of the MVR evaporation concentration device 7 is provided with a pneumatic conveying device 8 to concentrate the crystallized nitrate
  • the powder is connected to the inlet of the nitrate analysis tower 9 through the pneumatic conveying device 8, and the gas outlet of the nitrate analysis tower 9 is connected to the charcoal reduction tower 18.
  • the flue gas produced by coal powder combustion, mineral sintering, metal smelting and other processes first enters the first dust collector 1 to filter the flue dust in the flue gas, and the flue gas after dedusting is passed into ozone oxidation, in which NOx (mainly NO, volume fraction 95 %) high-order oxides (mainly NO 3 , N 2 O 5 etc.) that are oxidized to nitrogen, SO 2 in the flue gas is oxidized to SO 3 ; the flue gas after oxidation passes through the desulfurization tower 2 and the denitration tower in turn 3.
  • the second dust collector 4 is discharged through the chimney 5 afterwards.
  • the flue gas enters the desulfurization tower 2 and is washed by the alkaline desulfurization slurry before entering the denitration tower 3.
  • the desulfurization agent is a metal alkaline solution that can form a precipitate with SO 4 2- ions.
  • Common desulfurization agents are Ca(OH) 2 and Mg( OH) 2 etc.; alkaline desulfurization slurry reacts with SO 3 in the flue gas to form sulfate precipitates, which are dried in the drying unit 10 and stored in the sulfate warehouse 12; powdered sulfuric acid stored in the sulfuric acid warehouse 12 The salt and the powdered carbon material stored in the carbon material silo 13 and the iron powder in the iron powder silo 11 are fed into the fluidized bed reduction roaster 14 at a certain ratio for reduction roasting.
  • the roasting temperature is 800°C-1100°C.
  • roasting time 4s-200s, excess air coefficient ⁇ 1, the heat required for roasting is provided by the burner at the bottom of fluidized bed reduction roaster 14, the products after roasting are powdery roast slag and high temperature flue gas.
  • high-temperature flue gas with SO 2 content of 5%-30% and elemental sulfur vapor with 5%-25% high-temperature flue gas are produced first; high-temperature flue gas carries roasting slag out of the reduction roaster 14
  • the unsintered complete sulfates with the largest specific gravity in the roasting slag are separated and returned to the fluidized bed reduction roaster to continue to participate in the reaction; metal oxides, carbon powder and reducing gas with a smaller specific gravity enter the second separation
  • the metal oxide and carbon powder are separated from the reducing gas and enter the filtering device 17, the metal oxide reacts with water to form a corresponding alkaline solution, and returns to the desulfurization tower 2 for recycling as a desulfurization agent,
  • the reducing gas from the carbon thermal reduction tower 18 carries the powdered carbon material into the third separator 19, and the separated carbon powder returns to the carbon thermal reduction tower 18 to continue to participate in the reaction.
  • the reducing gas enters the reheater 20 Cooling, the energy released by this part of the reducing gas can be fully utilized in conjunction with the specific situation on site; the reducing gas after cooling enters the fine dust removal device 21, filtering out a small amount of roasting slag that has not been separated from the flue gas; finally, the reduction The gas enters the sulfur recovery device 22 to recover the sulfur and stores it in the sulfur storage tank 23, and the remaining spent gas is returned to the flue gas purification system of the large system.
  • the flue gas from the desulfurization tower 2 enters the wet denitration tower 3, is washed by the alkaline denitration slurry and enters the second dust collector 4, and the dedusted flue gas is discharged through the chimney 5; wherein the alkaline denitrification slurry and nitrogen in the flue gas
  • the higher-order oxides (mainly NO 3 , N 2 O 5, etc.) react to form a soluble nitrate solution; the nitrate solution is powered by the waste liquid pump and passes through the membrane concentration device 6 and the MVR evaporation concentration device 7 in order to convert the soluble Nitrate crystals are powdery solids. It is transported to the nitrate analysis tower 9 through the pneumatic conveying device 8.
  • the nitrate analysis tower 9 the nitrate is heated to 400°C-600°C, the reaction time is 10 ⁇ 200s, and the heat is generated by the waste heat generated by the iron-carbon reduction system; Nitrate is decomposed into solid metal oxide, N 2 , O 2 and high concentration NOx at this temperature, where the solid metal oxide is returned to the denitration tower 3 for recycling as a denitration agent, and the gas is sent to the reduction roaster 14, NOx is at high temperature It is catalytically reduced to non-polluting N 2 by iron-carbon materials.
  • the above-mentioned gas delivery process is provided with the delivery power by the induced draft fan or the blower.
  • An air lock feeder is installed at the outlet of the carbon material silo 13, the sulfate silo 12, and the iron powder silo 11, which accurately controls the amount of feed and ensures the tightness of the system.
  • the reduction roasting furnace is provided with an insulation layer on the outside and a burner at the bottom of the furnace chamber, which helps maintain the temperature in the reaction furnace and promote the reaction.
  • reaction product is elemental sulfur vapor, CO 2 , CO and other gases, reaction time and reaction temperature, gas atmosphere, particle size, equivalent Ratio and gas-solid mixing are closely related.
  • the reducing gas passes through the high-temperature separator to separate the powdery roasting slag, and then passes through the reheater to cool down, and then enters the fine powder separator for secondary dust removal.
  • the sulfur is condensed and recovered by the sulfur condenser. The purity of recovered sulfur reaches more than 99.7%, which meets the standards of industrial sulfur first-class products.
  • the metal oxides analyzed from the analysis tower react with water to generate the corresponding alkaline solution, which is returned to the out-of-stock tower for recycling.
  • the fluidized bed reduction roasting furnace may be in various forms such as air-flow bed, bubbling bed, micro-fluidized bed, spouted bed and fluidized bed, and may also be in various forms such as U-type furnace and ⁇ -type furnace.
  • the sulfate has a particle size of 60 ⁇ m-3 mm, and may be other metal sulfates such as calcium sulfate and magnesium sulfate.
  • the nitrate has a particle size of 60 ⁇ m-3 mm, and may be other metal nitrates such as calcium nitrate and sodium nitrate.
  • the carbon material with a particle size of 60 ⁇ m-3 mm, can be various types of carbon materials such as coal powder, activated coke, activated semi-coke, activated carbon, carbonized materials, graphite, and the like.
  • the calcination slag has a particle size of 60 ⁇ m-3 mm, and its main components are unreacted sulfates, metal oxides, etc., and also contains a small amount of impurities.
  • the alkaline desulfurization slurry may be an alkaline solution such as Ca(OH) 2 and Mg(OH) 2 .
  • the alkaline denitration slurry may be an alkaline solution such as NaSO 3 , NaOH, Ca(OH) 2 or the like.
  • the high-temperature flue gas has a temperature of 800°C-1100°C, and its main components are N 2 , S steam, SO 2 , CO, CO 2 and the like.
  • the reducing gas is mainly CO, and at the same time contains a small amount of H 2 , CH 4 and the like.
  • the reducing gas has a temperature of 800°C-1100°C, and its main components are N 2 , S steam, CO, CO 2 and the like.
  • the metal oxide has a particle size of 60 ⁇ m-3 mm, and may be metal oxides such as calcium oxide, sodium peroxide, and magnesium oxide.
  • the fuel can be burners in the form of pulverized coal, natural gas, diesel and other fuels.

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Abstract

一种硫/硝酸盐铁-炭还原制备硫磺并回收脱硫/硝剂的工艺，硫酸盐煅烧产生的高浓度SO 2烟气以及硝酸盐加热分解产生的NOx，可通过与铁-炭材料在高温下反应直接还原为单质硫蒸汽和N 2，然后依次经过除尘、降温、精除尘工艺后由硫磺回收装置回收得到硫磺，金属氧化物可代替石灰石等碱性矿物资源作为脱硫(硝)剂的原料，该工艺可实现脱硫剂、脱硝剂的循环使用。

Description

硫/硝酸盐铁-炭还原制备硫磺并回收脱硫/硝剂的工艺 技术领域
本发明属于污染物资源化利用领域，特别是涉及一种硫(硝)酸盐铁-炭还原制备硫磺同时回收脱硫(硝)剂的***及方法。
背景技术
随着我国环保要求的不断提高，燃煤电厂、钢铁厂等排放的含硫及NOx烟气需要设置烟气脱硫脱硝装置，其中以石灰石-石膏法为主的湿法脱硫机组占总装机容量的85％左右，该项技术虽然具有脱硫效率高、运行稳定等优点，但是需要消耗大量的石灰石，石灰石过度开采，不仅破坏生态环境，而且脱硫副产物为低品质脱硫石膏，脱硫石膏的主要成分为CaSO 4·2H 2O，同时也含有少量的其他金属离子硫酸盐，其价值低，难以利用。目前我国脱硫石膏年产量约为一亿吨，产量巨大，脱硫石膏难以处理对环境造成了巨大的危害。
臭氧脱硝技术比传统烟气脱硫脱硝工艺SCR及SNCR更适应日益严格的环保要求，采用臭氧的高级氧化技术不仅对NOx具有良好的脱除效果，同时对烟气中的其他有害污染物(如重金属汞等)也具有较好的脱除效果。在低温下进行氧化吸收等脱硝过程，有利于锅炉的能源回收利用，降低工程施工难度，利用国内现有较为成熟的湿法脱硫工艺并加以改进，使脱硫脱硝同时进行。通过特殊工艺控制脱硝反应过程，将NOx氧化成高价态的氧化物，然后用碱液吸收，脱硝效率高，能够达到超低排放要求。但是，硝酸盐极易溶于水，且硝酸盐中的金属离子对设备危害很大，形成的脱硝废液难以处理，造成二次污染。
现有的烟气硫资源回收技术多数为制备硫酸，但是硫酸的储存和运输困难，其利用价值较低。硫磺在所有含硫产品中分子量最低，单位价值高；储存运输成本较低；且硫磺可作为大多数含硫产品的生产原料，用途广泛。我国又是硫磺资源短缺的国家，每年硫磺进口量及消耗量位居世界前列，对外依存度高，硫磺作为重要的化工原料之一，其市场价值和应用价值远远大于硫酸。
发明内容
为了解决现有技术中存在的技术问题，本发明的目的是提供一种硫/硝酸盐铁-炭还原制备硫磺同时回收脱硫/硝剂的***及方法。该***及方法不仅可以缓解我国硫酸盐(主要是硫酸钙)及脱硝产生的硝酸盐废液难以处理的问题，同时将废固、废液资源化利用，在制备硫磺的同时可以回收脱硫剂与脱硝剂，实现了脱硫剂与脱硝剂的循环利用，减少了对石灰石等矿物资源的开采，保护生态环境，同时缓解了我国硫磺资源短缺的现状，降低硫磺资源的对外依存度。
为了解决以上技术问题，本发明的技术方案为：
一种硫/硝酸盐铁-炭还原制备硫磺并回收脱硫/硝剂的***，包括脱硫塔、脱硝塔、烟囱、干燥装置、还原焙烧炉、第一分离器、第二分离器、炭热还原塔、第三分离器、再热器、精除尘装置、硫磺回收装置、硫磺储仓、浓缩装置、气力输送装置和硝酸盐解析塔，其中，所述脱硫塔的烟气进口与烟气源连接，脱硫塔的烟气出口与脱硝塔的烟气进口连接，脱硝塔的烟气出口与湿式静电除尘器入口相连，湿式静电除尘器出口与烟囱入口相连；
脱硫塔的塔釜与干燥装置进口连接，干燥装置的出口与硫酸盐仓入口相连接，还原焙烧炉与铁粉源、碳粉源和硫酸盐仓连接；
脱硝塔的塔釜与浓缩装置的入口连接，浓缩装置的出口通过气力输送装置与硝酸盐解析塔的入口连接，硝酸盐解析塔的气体出口与炭热还原塔进口连接；
还原焙烧炉的出口端连接有第一分离器，第一分离器的固体出口与还原焙烧炉内部连通，第一分离器的气体出口与第二分离器进口连接，第二分离器的固体出口端连接有过滤装置；
第二分离器的气体出口端与炭热还原塔的进口连接，炭热还原塔的出口与第三分离器的进口连接，第三分离器的气体出口与再热器连接，再热器、精除尘装置、硫磺回收装置和硫磺储仓依次连接。
第三分离器的固体出口与炭热还原塔相连接；
硫酸盐的煅烧分解温度为1350℃-1400℃之间，但加入铁-炭材料后，硫酸盐煅烧分解温度大大降低，分解温度约为700℃-1100℃，温度的降低不仅减少了能耗，同时降低后的温度与炭热还原SO 2制备硫磺工艺的最佳温度相吻合，可以大大提高硫磺产品的转化率。硫酸盐煅烧，其主要成分为固体金属氧化物和高浓度SO 2气体，部分SO 2气体可以直接在流化床焙烧塔内与碳粉发生炭热还原反应，生成硫单质，铁粉的加入有助于SO 2还原反应的进行，有利于提高SO 2的转化率。剩余的SO 2气体随煅烧烟气流出还原焙烧炉。
硫单质在流化床焙烧塔内高温状态下为气态，从流化床焙烧塔出口流出的气流中携带有焙烧渣，焙烧渣中包括未焙烧完全的硫酸盐、金属氧化物和碳粉，其中比重最大的未焙烧完全的硫酸盐经第一分离器分离下来后，返回流化床还原焙烧炉继续参与反应；比重较小的金属氧化物、碳粉以及还原气进入第二分离器，第二分离器将金属氧化物与碳粉从还原气中分离下来，进入过滤装置。还原气携带少量未分离完全的焙烧渣从第二分离器出来后进入炭热还原塔中，还原气中的SO 2与碳材料反应，生成单质硫蒸气。炭热还原塔中出来的还原气携带粉状碳材料进入第三分离器中，分离下来的碳粉返回炭热还原塔中，还原气进入再热器降温，这部分还原气释放的能量可以结合现场具体情况，将这部分能量充分 利用；降温后的还原气进入精除尘装置，过滤掉前面两个高温分离器未分离下来的少量焙烧渣；最后，还原气进入硫磺回收装置回收得到硫磺并储存在硫磺储罐中，剩余乏气返回到大***的烟气净化***。
硝酸盐热稳定性差，加热分解有氧气放出，根据硝酸盐金属离子活性的不同，其分解温度也不同，常见臭氧氧化-湿法脱硝工艺形成的硝酸盐溶液，如硝酸钠溶液在400℃以上即分解为钠的氧化物、N 2、O 2及NOx，分解产生的固体金属氧化物可作为脱硝剂循环使用，浓缩后的气体产物送入炭热还原塔，在铁-炭催化剂存在的条件下，有助于降低NOx还原温度，同时可以提高NOx的转化率。
硫酸盐煅烧产生的高浓度SO 2烟气以及硝酸盐加热分解产生的NOx，可通过与铁-炭材料在高温下反应直接还原为单质硫蒸汽和N 2，然后依次经过除尘、降温、精除尘工艺后由硫磺回收装置回收得到硫磺，金属氧化物可代替石灰石等碱性矿物资源作为脱硫(硝)剂的原料，该工艺可实现脱硫剂、脱硝剂的循环使用。
优选的，所述过滤装置所述过滤装置内设置有腔室，腔室的横截面上设置有过滤网，过滤网的上端设置第一出口，过滤网的下端设置第二出口。
过滤装置内设置有腔室，腔室内不断通入水，水将落下的金属氧化物溶解，得到碱液，碱液自过滤装置的第二出口流出，输送至脱硫塔进行脱硫，过滤网将不溶于水的碳粉拦截，拦截后的固体浆液自过滤装置的第一出口流出，经过烘干后送入流化床还原焙烧炉烧掉。
优选的，所述脱硫塔的烟气进口端连接有第一除尘器。第一除尘器可以对烟气进行除尘，减少烟气中的固体颗粒含量，有利于改善脱硫塔内的工况。
进一步优选的，所述第一除尘器与脱硫塔之间的烟道与臭氧发生器连接。
臭氧发生器向除尘后的烟气内通入臭氧，臭氧将烟气中的NOx(主要是NO，体积分数95％左右)氧化成氮的高阶氧化物，主要为NO 3、N 2O 5等，烟气中的SO 2被氧化成SO 3，再进行脱硫脱硝时，烟气中的高阶氮氧化物和三氧化硫与碱液反应生成硝酸盐和硫酸盐。
优选的，所述脱硝塔与烟囱之间连接有第二除尘器。第二除尘器可以将烟气进行再次除尘，保证排放至大气中的烟气的洁净度。
优选的，第一除尘器和第二除尘器为布袋除尘器、旋风分离器、轴流分离器或静电除尘器。
优选的，所述浓缩装置包括膜浓缩装置和MVR蒸发浓缩装置，膜浓缩装置的进口与脱硝塔的塔釜连接，膜浓缩装置的出口与MVR蒸发浓缩装置的进口连接，MVR蒸发浓缩装置的出口设置气力输送装置。
膜浓缩装置和MVR蒸发浓缩装置对硝酸盐溶液进行二级浓缩，以保证将硝酸盐溶液中 的硝酸盐结晶为粉状固体。
优选的，所述干燥装置与还原焙烧炉之间设置有给料机。
所有流化床焙烧炉为：还原焙烧炉+炭热还原塔。所述炭热还原塔可以为流化床、气流床、鼓泡床等多种形式；
所述还原焙烧炉，可以为气流床、流化床、沸腾床、回转窑等多种形式。
进一步优选的，所述给料机为螺旋给料机或锁气给料机。
优选的，所述精除尘装置为金属网过滤器或陶瓷过滤器。
一种硫/硝酸盐铁-炭还原制备硫磺并回收脱硫/硝剂的工艺，包括如下步骤：
烟气经过除尘、臭氧氧化、碱洗脱硫、碱洗脱硝后排放；
脱硫过程中产生的硫酸盐沉淀经过干燥后与碳粉、铁粉按照设定比例输送至还原焙烧炉进行焙烧还原，焙烧的温度为800℃-1100℃，焙烧时间4s-200s；还原焙烧所需热量由燃烧器提供。燃烧器燃料可以为煤粉、天然气、汽油、柴油等燃料。
脱硝过程中产生的硝酸盐溶液经过浓缩结晶后产生硝酸盐粉末，硝酸盐粉末经过高温分解成固体金属氧化物和混合气，混合气输送至还原焙烧炉中经焙烧还原成氮气；
还原焙烧炉出口处流出的气体中携带的比重大的未焙烧完全的硫酸盐经第一分离器分离下来后，返回还原焙烧炉继续参与反应，比重小的金属氧化物和碳粉经第二分离器分离下来，进入过滤装置，金属氧化物溶解在过滤装置中的水中，成为碱液，碳粉被过滤装置拦截，烘干再利用；
焙烧气体经过冷凝除尘、硫磺回收后，依次进入脱硫塔、脱硝塔进行处理，最后排放。
优选的，输送至还原焙烧炉中的硫酸盐的粒径为60μm-3mm，硝酸盐的粒径为60μm-3mm，碳粉的粒径为60μm-3mm，铁粉的粒径为60μm-500μm。
进一步优选的，还原焙烧炉中的硫酸盐、碳粉、铁粉的质量比为8-11:1-2:1-2。
优选的，所述硝酸盐粉末高温分解的温度为400-600℃，反应的时间为10-200s。
本发明的有益效果为：
本发明提出一种硫(硝)酸盐铁-炭还原制备硫磺同时回收脱硫(硝)剂的工艺及装置。针对烟气湿法脱硫-臭氧脱硝工艺中产生的硫酸盐及硝酸盐，利用流化床还原焙烧炉、硝酸盐解析塔、膜浓缩、MVR蒸发浓缩、高温分离器、硫磺回收装置等，通过精确控制反应温度和反应条件，分别将湿法脱硫-臭氧脱硝产生的硫酸盐废固和硝酸盐废液进行热处理，在制备硫磺回收固废中硫资源的同时实现了脱硫(硝)剂的循环利用，不仅可以缓解我国硫磺资源紧缺的现状，降低硫资源对外依存度，同时实现了硫酸盐的资源化利用，为目前难以处理的硫酸盐固废提供了全新的可持续的无污染的处理方式，对于湿法脱硫-臭氧脱硝等 相关行业具有重大意义，具有广阔的市场前景。
附图说明
构成本申请的一部分的说明书附图用来提供对本申请的进一步理解，本申请的示意性实施例及其说明用于解释本申请，并不构成对本申请的不当限定。
图1为一种硫(硝)酸盐铁-炭还原制备硫磺同时回收脱硫(硝)剂的***的结构示意图。
其中：1、第一除尘器，2、脱硫塔，3、脱销塔，4、第二除尘器，5、烟囱，6、膜浓缩装置，7、MVR蒸发浓缩装置，8、气力输送装置，9、硝酸盐解析塔，10、干燥装置，11、铁粉仓，12、硫酸盐仓，13、碳材料仓，14、还原焙烧炉，15、第一分离器，16、第二分离器，17、过滤装置，18、炭热还原塔，19、第三分离器，20、再热器，21、精除尘装置，22、硫磺回收装置，23、硫磺储仓。
具体实施方式
应该指出，以下详细说明都是示例性的，旨在对本申请提供进一步的说明。除非另有指明，本文使用的所有技术和科学术语具有与本申请所属技术领域的普通技术人员通常理解的相同含义。
需要注意的是，这里所使用的术语仅是为了描述具体实施方式，而非意图限制根据本申请的示例性实施方式。如在这里所使用的，除非上下文另外明确指出，否则单数形式也意图包括复数形式，此外，还应当理解的是，当在本说明书中使用术语“包含”和/或“包括”时，其指明存在特征、步骤、操作、器件、组件和/或它们的组合。
如图1所示，一种硫/硝酸盐铁-炭还原制备硫磺并回收脱硫/硝剂的***，包括脱硫塔2、脱硝塔3、烟囱5、干燥装置10、还原焙烧炉14、第一分离器15、第二分离器16、炭热还原塔18、第三分离器19、再热器20、精除尘装置21、硫磺回收装置22、硫磺储仓23、浓缩装置、气力输送装置8和硝酸盐解析塔9，其中，所述脱硫塔2的烟气进口通过第一除尘器1与烟气源连接，脱硫塔2的烟气出口与脱硝塔3的烟气进口连接，脱硝塔3的烟气出口通过第二除尘器4与烟囱5连接；第一除尘器1和第二除尘器4可以为布袋除尘器、旋风分离器、轴流分离器或静电除尘器。
脱硫塔2的塔釜与干燥装置10进口连接，干燥装置10的出口通过给料机与硫酸盐仓12连接，还原焙烧炉14还与铁粉仓11、碳材料仓13和硫酸盐仓12连接；给料机为螺旋给料机或锁气给料机。
还原焙烧炉14的出口端连接有第一分离器15，第一分离器15的固体出口与还原焙烧炉14内部连通，第一分离器15的气体出口与第二分离器16进口连接，第二分离器16的 固体出口端连接有过滤装置17，所述过滤装置17内设置有腔室，腔室的横截面上设置有过滤网，过滤网的上端设置第一出口，过滤网的下端设置第二出口；
第二分离器16的气体出口端与炭热还原塔18的进口连接，炭热还原塔18的出口与第三分离器19的进口连接，第三分离器19的气体出口与再热器20连接，再热器20、精除尘装置21、硫磺回收装置22和硫磺储仓23依次连接；精除尘装置21为金属网过滤器或陶瓷过滤器。所述硫磺回收装置22的结构与克劳斯工艺硫回收装置的结构基本相同。第三分离器固体出口与炭热还原塔18连接。
第一分离器15和第二分离器16可以为高温旋风分离器、高温轴流分离器等多种形式的分离器。
再热器20的换热介质可以是冷却水、空气、导热油、熔盐等多种类型。
膜浓缩装置6的进口与脱硝塔3的塔釜连接，膜浓缩装置6的出口与MVR蒸发浓缩装置7的进口连接，MVR蒸发浓缩装置7的出口设置气力输送装置8，浓缩结晶后的硝酸盐粉末通过气力输送装置8与硝酸盐解析塔9的入口连接，硝酸盐解析塔9的气体出口与炭热还原塔18连接。
煤粉燃烧、矿物烧结、金属冶炼等过程产生的烟气首先进入第一除尘器1过滤掉烟气中的烟尘，除尘后的烟气通入臭氧氧化，其中NOx(主要是NO，体积分数95％左右)被氧化成氮的高阶氧化物(主要为NO 3、N 2O 5等)，烟气中的SO 2被氧化成SO 3；氧化后的烟气依次经过脱硫塔2、脱硝塔3、第二除尘器4后通过烟囱5排出。
烟气进入脱硫塔2中，通过碱性脱硫浆液洗涤后进入脱硝塔3，脱硫剂为可以与SO 4 2-离子形成沉淀的金属碱性溶液，常用脱硫剂为Ca(OH) 2、Mg(OH) 2等；碱性脱硫浆液与烟气中的SO 3反应，形成硫酸盐沉淀，硫酸盐沉淀经干燥装置10干燥后储存在硫酸盐仓12中；存储在硫酸仓12中的粉状硫酸盐与储存在碳材料仓13中的粉状碳材料、铁粉仓11中的铁粉以一定的配比送入流化床还原焙烧炉14进行还原焙烧，焙烧温度为800℃-1100℃，焙烧时间4s-200s，过量空气系数<1，焙烧的所需热量由流化床还原焙烧炉14底部燃烧器提供，焙烧后的产物为粉状焙烧渣与高温烟气。还原焙烧过程中，首先产生SO 2含量为5％-30％的高温烟气，单质硫蒸气的含量为5％-25％的高温烟气；高温烟气携带焙烧渣从还原焙烧炉14中出来后进入第一分离器15，焙烧渣中比重最大的未焙烧完全的硫酸盐分离下来返回流化床还原焙烧炉继续参与反应；比重较小的金属氧化物、碳粉以及还原气进入第二分离器16，在此过程中，金属氧化物与碳粉从还原气中分离下来，进入过滤装置17，金属氧化物与水反应生成相应的碱溶液，返回脱硫塔2作为脱硫剂循环利用，不溶于水的碳粉过滤干燥后送入还原焙烧炉14烧掉；还原气携带少量未分离完全的焙烧渣从第二分离器16出来 后进入炭热还原塔18，其中高浓度SO 2被碳材料或还原性气体还原为单质硫蒸汽，炭热还原塔18出来的还原气携带粉状碳材料进入第三分离器19，分离下来碳粉返回炭热还原塔18继续参与反应，还原气进入再热器20降温，这部分还原气释放的能量可以结合现场具体情况，将这部分能量充分利用；降温后的还原气进入精除尘装置21，过滤掉烟气中未分离下来的少量焙烧渣；最后，还原气进入硫磺回收装置22回收得到硫磺并储存在硫磺储罐23中，剩余乏气返回到大***的烟气净化***。
从脱硫塔2中出来的烟气进入湿法脱硝塔3，通过碱性脱硝浆液洗涤后进入第二除尘器4，除尘后的烟气通过烟囱5排出；其中碱性脱硝浆液与烟气中氮的高阶氧化物(主要是NO 3、N 2O 5等)反应，形成可溶性硝酸盐溶液；硝酸盐溶液通过废液泵提供动力，依次经过膜浓缩装置6和MVR蒸发浓缩装置7，将可溶性硝酸盐结晶为粉状固体。通过气力输送装置8输送至硝酸盐解析塔9，在硝酸盐解析塔9中，硝酸盐被加热到400℃-600℃，反应时间10～200s，由铁-炭还原***产生的余热提供热量；硝酸盐在此温度下分解为固体金属氧化物、N 2、O 2及高浓度NOx，其中固体金属氧化物返回脱硝塔3作为脱硝剂循环利用，气体输送到还原焙烧炉14，NOx在高温下被铁-碳材料催化还原为无污染的N 2。
上述气体输送过程由引风机或送风机提供输送动力。
碳材料仓13出口、硫酸盐仓12、铁粉仓11出口处设锁气给料机，精确控制输料量的同时保证***的密封性。
还原焙烧炉，外部设保温层，炉膛底部设燃烧器，有助于维持反应炉内的温度，促进反应的进行。
SO 2与碳材料或者还原性气体在500℃-1000℃环境下发生氧化还原反应，其反应产物为单质硫蒸气、CO 2、CO等气体，反应时间与反应温度、气体氛围、粒径、当量比、气固混合密切相关。
还原气经过高温分离器分离粉状焙烧渣，再经再热器降温后进入细粉分离器进行二次除尘，由硫磺冷凝器冷凝回收硫磺。回收硫磺纯度达到99.7％以上，符合工业硫磺一等品标准。
从解析塔解析出来的金属氧化物与水反应生成相应的碱溶液，返回脱销塔循环利用。
所述流化床还原焙烧炉，可以为气流床、鼓泡床、微流化床、喷动床及流化床等多种形式，也可为U型炉、π型炉等多种形式。
所述硫酸盐，粒径60μm-3mm，可为硫酸钙、硫酸镁等其他金属硫酸盐。
所述硝酸盐，粒径60μm-3mm，可为硝酸钙、硝酸钠等其他金属硝酸盐。
所述碳材料，粒径60μm-3mm，可以为煤粉、活性焦、活性半焦、活性炭、炭化料、 石墨等多种类型的碳材料。
所述焙烧渣，粒径60μm-3mm，主要成分为未反应的硫酸盐、金属氧化物等，同时含有少量杂质。
所述碱性脱硫浆液，可以为Ca(OH) 2、Mg(OH) 2等碱性溶液。
所述碱性脱硝浆液，可以为NaSO 3、NaOH、Ca(OH) 2等碱性溶液。
所述高温烟气，温度800℃-1100℃，主要成分为N 2、S蒸汽、SO 2、CO、CO 2等。
所述还原性气体，主要为CO，同时含有少量H 2、CH 4等。
所述还原气，温度800℃-1100℃，主要成分为N 2、S蒸汽、CO、CO 2等。
所述金属氧化物，粒径60μm-3mm，可为氧化钙、过氧化钠、氧化镁等金属氧化物。
所述燃烧器，其燃料可以为煤粉、天然气、柴油等多种燃料形式的燃烧器。
以上所述仅为本申请的优选实施例而已，并不用于限制本申请，对于本领域的技术人员来说，本申请可以有各种更改和变化。凡在本申请的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本申请的保护范围之内。

Claims (10)

  1. 一种硫/硝酸盐铁-炭还原制备硫磺并回收脱硫/硝剂的***，其特征在于：包括脱硫塔、脱硝塔、烟囱、干燥装置、还原焙烧炉、第一分离器、第二分离器、炭热还原塔、第三分离器、再热器、精除尘装置、硫磺回收装置、硫磺储仓、浓缩装置、气力输送装置和硝酸盐解析塔，其中，所述脱硫塔的烟气进口与烟气源连接，脱硫塔的烟气出口与脱硝塔的烟气进口连接，脱硝塔的烟气出口与湿式静电除尘器入口相连，湿式静电除尘器出口与烟囱入口相连；
    脱硫塔的塔釜与干燥装置进口连接，干燥装置的出口与硫酸盐仓入口相连接，硫酸盐仓与还原焙烧炉连接，还原焙烧炉还与铁粉源和碳粉源连接；
    脱硝塔的塔釜与浓缩装置的入口连接，浓缩装置的出口通过气力输送装置与硝酸盐解析塔的入口连接，硝酸盐解析塔的出口与炭热还原塔进口连接；
    还原焙烧炉的出口端连接有第一分离器，第一分离器的固体出口与还原焙烧炉内部连通，第一分离器的气体出口与第二分离器进口连接，第二分离器的固体出口端连接有过滤装置；
    第二分离器的气体出口端与炭热还原塔的进口连接，炭热还原塔的出口与第三分离器的进口连接，第三分离器的气体出口与再热器连接，再热器、精除尘装置、硫磺回收装置和硫磺储仓依次连接，第三分离器的固体出口与炭热还原塔相连。
  2. 根据权利要求1所述的***，其特征在于：所述过滤装置内设置有腔室，腔室的横截面上设置有过滤网，过滤网的上端设置第一出口，过滤网的下端设置第二出口。
  3. 根据权利要求1所述的***，其特征在于：所述脱硫塔的烟气进口端连接有第一除尘器，第一除尘器与脱硫塔之间的烟道与臭氧发生器连接。
  4. 根据权利要求1所述的***，其特征在于：所述浓缩装置包括膜浓缩装置和MVR蒸发浓缩装置，膜浓缩装置的进口与脱硝塔的塔釜连接，膜浓缩装置的出口与MVR蒸发浓缩装置的进口连接，MVR蒸发浓缩装置的出口设置气力输送装置。
  5. 根据权利要求1所述的***，其特征在于：所述干燥装置与还原焙烧炉之间设置有给料机。
  6. 根据权利要求1所述的***，其特征在于：所述精除尘装置为金属网过滤器或陶瓷过滤器。
  7. 一种硫/硝酸盐铁-炭还原制备硫磺并回收脱硫/硝剂的工艺，其特征在于：包括如下步骤：
    烟气经过除尘、臭氧氧化、碱洗脱硫、碱洗脱硝后排放；
    脱硫过程中产生的硫酸盐沉淀经过干燥后与碳粉、铁粉按照设定比例输送至还原焙烧 炉进行焙烧还原，焙烧的温度为800℃-1100℃，焙烧时间4s-200s；
    脱硝过程中产生的硝酸盐溶液经过浓缩结晶后产生硝酸盐粉末，硝酸盐粉末经过高温分解成固体金属氧化物和混合气，混合气输送至还原焙烧炉中经焙烧还原成氮气；
    还原焙烧炉出口处流出的气体中携带的比重大的未焙烧完全的硫酸盐经第一分离器分离下来后，返回还原焙烧炉继续参与反应，比重小的金属氧化物和碳粉经第二分离器分离下来，进入过滤装置，金属氧化物溶解在过滤装置中的水中，成为碱液，碳粉被过滤装置拦截，烘干再利用；
    焙烧气体经过冷凝除尘、硫磺回收后，依次进入脱硫塔、脱硝塔进行处理，最后排放。
  8. 根据权利要求7所述的工艺，其特征在于：输送至还原焙烧炉中的硫酸盐的粒径为60μm-3mm，硝酸盐的粒径为60μm-3mm，碳粉的粒径为60μm-3mm，铁粉的粒径为60μm-500μm。
  9. 根据权利要求8所述的工艺，其特征在于：还原焙烧炉中的硫酸盐、碳粉、铁粉的质量比为8-11:1-2:1-2。
  10. 根据权利要求7所述的工艺，其特征在于：所述硝酸盐粉末高温分解的温度为400-600℃，反应的时间为10-200s。
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