WO2020206568A1 - 一种高铝煤烟气净化中污染物综合回收工艺 - Google Patents

一种高铝煤烟气净化中污染物综合回收工艺 Download PDF

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WO2020206568A1
WO2020206568A1 PCT/CN2019/000165 CN2019000165W WO2020206568A1 WO 2020206568 A1 WO2020206568 A1 WO 2020206568A1 CN 2019000165 W CN2019000165 W CN 2019000165W WO 2020206568 A1 WO2020206568 A1 WO 2020206568A1
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flue gas
aluminum
purification
adsorption
liquid
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PCT/CN2019/000165
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English (en)
French (fr)
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崔怀奇
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茏源（北京）环保科技有限公司
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/77—Liquid phase processes
    • B01D53/78—Liquid phase processes with gas-liquid contact
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D47/00—Separating dispersed particles from gases, air or vapours by liquid as separating agent
    • B01D47/06—Spray cleaning
    • 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
    • B01D53/02—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 by adsorption, e.g. preparative gas chromatography
    • B01D53/04—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 by adsorption, e.g. preparative gas chromatography with stationary adsorbents
    • 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
    • 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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/20—Silicates
    • C01B33/32—Alkali metal silicates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
    • C01F7/34—Preparation of aluminium hydroxide by precipitation from solutions containing aluminium salts
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/66—Nitrates, with or without other cations besides aluminium
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/68—Aluminium compounds containing sulfur
    • C01F7/74—Sulfates
    • C01F7/743—Preparation from silicoaluminious materials, e.g. clays or bauxite
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G49/00—Compounds of iron
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G49/00—Compounds of iron
    • C01G49/0009—Preparation involving a liquid-liquid extraction, an adsorption or an ion-exchange
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G49/00—Compounds of iron
    • C01G49/02—Oxides; Hydroxides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G49/00—Compounds of iron
    • C01G49/14—Sulfates
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B21/00—Obtaining aluminium
    • C22B21/0015—Obtaining aluminium by wet processes
    • C22B21/0023—Obtaining aluminium by wet processes from waste materials
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/006—Wet processes
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/02—Working-up flue dust
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/10—Oxidants
    • B01D2251/108—Halogens or halogen compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/50—Inorganic acids
    • B01D2251/504—Nitric acid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/50—Inorganic acids
    • B01D2251/506—Sulfuric acid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
    • B01D2253/10—Inorganic adsorbents
    • B01D2253/102—Carbon
    • 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
    • B01D2258/00—Sources of waste gases
    • B01D2258/02—Other waste gases
    • B01D2258/0283—Flue gases
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2259/00—Type of treatment
    • B01D2259/40—Further details for adsorption processes and devices
    • B01D2259/40083—Regeneration of adsorbents in processes other than pressure or temperature swing adsorption
    • B01D2259/40088—Regeneration of adsorbents in processes other than pressure or temperature swing adsorption by heating
    • B01D2259/40092—Regeneration of adsorbents in processes other than pressure or temperature swing adsorption by heating using hot liquid
    • 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
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency
    • Y02P20/129—Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines

Definitions

  • the invention relates to the field of atmospheric environment treatment, in particular to an industrial flue gas purification technology for comprehensive treatment of gaseous pollutants, liquid pollutants and solid pollutants produced by the combustion of high-alumina coal in coal-fired boilers.
  • the annual discharge of high-aluminum fly ash in my country is about 25 million tons, and the accumulated storage exceeds 100 million tons.
  • the large amount of high-aluminum fly ash has caused serious air, water and soil pollution, due to the formation of high-alumina coal in the geological age. It is complicated.
  • the sulfur content in coal is also relatively high.
  • the sulfur dioxide produced during the combustion process is discharged into the atmosphere with the flue gas and is absorbed by rain and snow to form acid rain on the ground, causing harm to human health, surface plants and soil.
  • the gaseous pollution and solid pollution formed by combustion seriously harm human health and the ecological environment. Therefore, the comprehensive treatment of pollutants produced by burning high-aluminum coal is a cyclic system technology to be developed.
  • Conventional technology adopts high-efficiency combustion method to fully burn high-aluminum coal, and uses alkali method, calcium method or other methods to transform and remove sulfur dioxide generated during the combustion of high-aluminum coal; collect and store high-aluminum fly ash, and then use Bayer Extraction method, one-step hydrothermal method, two-step hydrothermal method to extract AL 2 O 3 from high alumina fly ash.
  • the step-by-step operation of these methods not only increases the difficulty of the treatment, but also greatly increases the treatment cost, resulting in an increase in secondary pollutants after the use of high-aluminum coal, which seriously affects the resource utilization of high-aluminum coal.
  • the Zhungeer, Tuyou, and Zhuozishan areas in Inner Mongolia are my country's unique high-aluminum coal resource rich areas. It has been proved that coal and aluminum coexist with coal resources of more than 50 billion tons, and the alumina content in the coal is 10%-13%. , The alumina content in fly ash is as high as 40%-55%, and the potential high-alumina fly ash resource is 15 billion tons, which is far higher than the total reserves of my country's proven bauxite resources.
  • the Zhungeer Coalfield has an annual output of 100 million tons of high-alumina coal, which can produce 30 million tons of high-alumina fly ash, and can extract 12 million tons of alumina, equivalent to 25 million tons of bauxite, which is equivalent to the annual import volume.
  • the reserves of Zhungeer high-aluminum coal equivalent to high-aluminum fly ash reached 7 billion tons. Extracting all the AL 2 O 3 from it can extend the guarantee period of aluminum resources in China by 50-60 years.
  • the present invention is an improvement to the coal-fired flue gas purification technology, especially an innovation in the treatment and comprehensive utilization of pollutants produced by the combustion of high-aluminum coal.
  • physical adsorption and chemical adsorption are used to adsorb and remove sulfur dioxide in flue gas; oxidation + adsorption is used to remove nitrogen oxides in flue gas; and water-soluble immersion desorption method is used to remove the two adsorbates separately ;
  • the mixed convection absorption method of desorption liquid and flue gas mist the aluminum oxide and iron oxide in the smoke are absorbed and converted into aluminum sulfate, aluminum nitrate, iron sulfate, and iron nitrate; according to the difference of the solubility of each component
  • the step crystallization method separates aluminum sulfate and iron sulfate; the aluminum sulfate and aluminum nitrate are decomposed into aluminum hydroxide, ammonium sulfate, and ammonium nitrate by the
  • a comprehensive recovery process for pollutants in the purification of high-aluminum coal flue gas realized by the present invention, while treating flue gas pollutants, combines gaseous pollutants, liquid pollutants, and solid pollutants through a combination of various technologies to mutually suppress each other. China will mutually exist, decompose, and purify, and finally realize the purpose of treating waste with waste.
  • the boiler flue gas first passes through the hot air device of the indirect heat exchanger to convert natural air into hot air, and then passes through the evaporation system of the indirect heat exchanger, and passes through the first evaporation system in the evaporation system.
  • the desorption liquid is concentrated, the synthetic liquid is concentrated by the second evaporation system, and the mixed solution after the ammonia metathesis is evaporated and concentrated by the third evaporation system, and the ammonia molecules are driven out.
  • activated carbon modified by loaded ions is selected to be used as an adsorbent carrier, and the carrier is made into a series winding that enables the flue gas to maintain the largest area and the longest contact with it under the minimum wind resistance
  • Type adsorption purification carrier reasonable layout of the adsorption carrier, combined into a flue gas purification system with a staggered structure.
  • the flue gas is continuously in contact with the adsorbent through reciprocating tandem, and the sulfur dioxide molecules in the flue gas are rapidly adsorbed during the contact due to their high boiling point and strong activity, thereby completing the desulfurization in the adsorption purification process.
  • the open-cell foam glass is made into a catalytic carrier of a certain specification, the carrier is installed in the oxidation section of the purification system, and the tandem adsorption purification section forms a composite purification structure;
  • the oxidant is poured by the method, so that the oxidant becomes a liquid film on the wall of the foam glass ball in the flow.
  • the nitric oxide in the flue gas contacts with the oxidant on the spherical wall, and the oxygen atoms in the flue gas are quickly absorbed and oxidized into two Nitrogen oxide and nitrogen dioxide are adsorbed by the adsorbent when passing through the tandem adsorption system to complete the denitration of the oxidation + adsorption system.
  • the adsorbate in the adsorbent carrier is dissolved and desorbed by the water vapor dissolution desorption method and/or the hot water dissolution desorption method,
  • the adsorbate molecules SO 2 , NO X ) are hydrated to synthesize dilute sulfuric acid and dilute nitric acid.
  • the desorption liquid is concentrated and then atomized separately in the gas mist convective conversion purification system, so that the dilute sulfuric acid mist liquid is in convective contact with the flue gas to absorb the aluminum oxide in the smoke and convert it into aluminum sulfate, Absorb ferric oxide and convert it into ferric sulfate; make the dilute nitric acid mist liquid and flue gas convectively contact to absorb the aluminum oxide in the smoke and convert it into aluminum nitrate, and absorb the ferric oxide into iron nitrate; the mixed solution is clarified and precipitated The unconverted impurities in the smoke and dust, the silica in the impurities is dehydrated and then fused with sodium hydroxide in a high-speed stirred reactor to form sodium metaaluminate; the clear liquid is concentrated and then cooled and crystallized to separate aluminum sulfate from iron sulfate , And further crystallize into finished products of aluminum sulfate, iron
  • the mother liquor containing aluminum sulfate or aluminum nitrate produced in the previous method is mixed with ammonia water for metathesis.
  • ammonia molecules dissolved in water ionize ammonium ions.
  • the aluminum hydroxide is dehydrated and dried into a finished product; the ammonium sulfate and ammonium nitrate solution are heated and decomposed to drive out ammonia molecules, containing sulfuric acid Or the clear liquid of nitric acid repeats the previous method to absorb the aluminum oxide and iron oxide in the smoke and dust; the ammonia molecules are dissolved in the mixed solution and continue to metathesize, and the cycle is used to realize the aluminum oxide and iron oxide in the fly ash. Extraction of iron.
  • Boiler flue gas is aggregated and sent to the gas-liquid indirect heat exchanger under the push force of the front-end fan or the attraction of the rear-end induced draft fan.
  • the heat exchanger is divided into two units.
  • the first unit is the gas-gas indirect heat exchanger.
  • the second unit is a liquid-gas indirect heat exchanger.
  • the air pipes are arranged horizontally. Natural wind flows in the air pipe under the blowing force or gravitational force of the fan, and the hot flue gas flows from the pipe to the pipe. The gap crosses horizontally, and it exchanges heat with the natural wind in the tube while passing through.
  • the natural wind absorbs the heat of the flue gas through the heat transfer effect of the tube wall and winds forward in the heat exchanger in an S shape, after repeated heating After the temperature reaches the required standard, it enters the drying system under the blower.
  • the pipes are arranged longitudinally, the desorption liquid and the decomposition liquid absorb heat to the flue gas through the heat transfer of the tube wall in the tube, and the high-temperature flue gas is cut in transversely and loses heat through the tube, and the desorption liquid and the decomposition liquid are changing Concentrated by evaporation under the action of heat.
  • the unit is divided into two-stage ammonia distillation system and two-stage evaporation system.
  • the two-stage ammonia distillation system includes desorption liquid ammonia vaporization and double decomposition liquid ammonia vaporization.
  • the driven ammonia gas enters the adsorption system or feeds through the ammonia channel.
  • Ammonia metathesis system the two-stage evaporation system is divided into a desorption liquid evaporation section after ammonia distillation and a metathesis liquid evaporation section after ammonia distillation.
  • the water vapor generated during the evaporation process is used for the adsorption of adsorbate in the adsorption process through the steam pipeline ,
  • the concentrated liquid is intermittently discharged from the bottom discharge port into the next process.
  • the flue gas is blown into the gas gathering bin under the action of the front-end fan, and the air pressure is balanced up to the first stage water mist dust removal section under the distribution of the flue gas distributor, and the desorption liquid generated in the subsequent process passes through
  • the atomization of the high-pressure nozzle produces convective contact with the rising flue gas.
  • the flue dust is dissolved in the desorption liquid and flows downstream to the liquid collection area.
  • the smoke and dust are removed by the sedimentation method, and the number of nodes in the water mist dust removal section is determined according to the removal efficiency.
  • the flue gas gathering bin described in this embodiment is a triangular annular gas bin with the upper half of the inverted cone at the bottom of the device closed by a partition and the air inlets are evenly distributed on the inner circumference.
  • the flue gas enters from the lower air outlet and then passes through the circumferential air inlet Enter the device.
  • the flue gas distributor described in this embodiment is a number of mushroom cap air distributors divided into certain proportions at the bottom of the water mist dust removal section.
  • the flue gas in the lower part enters the mushroom cap from the central tube and then is discharged from the peripheral air duct.
  • the function is to evenly distribute the flue gas, and on the other hand, to prevent the spray liquid from the upper part from flowing into the lower device.
  • the flue gas enters the staggered string-wound adsorption purification section, and diffuses outward through the adsorbent in the interlayer through the central tube through the densely distributed purifier, and the flue gas passes through the adsorbent (special activated carbon surface).
  • the water molecules in the flue gas and the active layer on the surface of the activated carbon produce a complex ionization reaction to form a hydroxyl functional group (-OH), namely: H 2 O ⁇ -OH * +H + , (* means adsorption state, -OH represents a hydroxyl functional group).
  • the oxygen molecules in the flue gas are also catalyzed and decomposed into oxygen atoms by the activation energy of the activated carbon surface, that is, O 2 ⁇ 2O * .
  • the production of hydroxyl functional groups and oxygen atoms generates multi-position active complexes for the active center on the surface of activated carbon, namely: -OH * , O * .
  • Nitric oxide molecules in the flue gas rapidly obtain oxygen under the action of the multi-position active complexes.
  • the flue gas travels through the device body from bottom to top section by section according to the first section of the string winding mode.
  • the purification cylinders in the upper and lower sections are distributed in a staggered manner.
  • the densely packed purifiers do the same tandem adsorption.
  • the SO 2 in the gas is preferentially adsorbed due to its polarity, boiling point, and activity higher than other molecules.
  • Part of the NO is oxidized to NO 2 under the action of the surface active complexes of the adsorption layer.
  • the flue gas is purified by a number of overlapping purification layers. Purpose of the first level.
  • the method is to pass the first-stage purified tail gas through the peripheral shunt purifier again.
  • the segmented tandem adsorption purification system performs repurification, and the process is realized through reoxidation and resorption.
  • Said re-oxidation is to pass the flue gas into an oxidation box in which a catalytic carrier made of open-cell foam glass is installed according to a certain specification, and the oxidation section and the tandem adsorption purification section form a composite purification structure.
  • the oxidant is poured into the catalytic carrier by spraying, and the oxidant is sodium hypochlorite, sodium chlorite, etc.
  • the oxidant becomes a liquid film on the wall of the foam glass spherical wall in the flow of the catalytic carrier.
  • the nitric oxide in the flue gas contacts the oxidant on the spherical wall, and the oxygen atoms in the flue gas are quickly absorbed and oxidized to nitrogen dioxide.
  • Nitrogen dioxide is adsorbed by the adsorbent when passing through the tandem adsorption system, so as to achieve the maximum denitration of the process.
  • the adsorbent absorbs enough molecules, the adsorption efficiency begins to decrease, and the adsorption gradually enters a saturated state, and the desorption process needs to be started.
  • the desorption used in this process is divided into two methods, one is to dissolve the adsorbate in the shunt purification system through the infiltration and dissolution of gaseous water molecules, and the other is to dissolve the adsorbate in the main stacking purification system through the leaching and dissolution of liquid water molecules.
  • the water vapor passes through the steam distributor alternately into the shunt purifier, and is immersed in the adsorption pores of the activated carbon under the action of its diffusive force, and is fused and transformed with the adsorbate, so that the new molecules will be transformed by the expansion force during the generation process.
  • the second is The liquid water is transported through the high-pressure water pipe into the purification layer of each section of the main body, and sprayed to the corresponding purification unit through the spray eye of the desorption ring pipe, and the adsorbate is desorbed according to the above principle.
  • the dilute sulfuric acid in the mist liquid absorbs alumina and iron oxide and converts it into aluminum sulfate and iron sulfate.
  • Nitric acid absorbs aluminum oxide and iron oxide and converts them into aluminum nitrate and iron nitrate.
  • the present invention uses a solubility difference separation method to separate iron sulfate from the mixed solution of iron sulfate and aluminum sulfate.
  • the liquid is cooled to about 25°C to realize the separation of the two components (according to the observation of the solubility of aluminum sulfate and iron sulfate solutions at 25°C: AL 2 (SO 4 ) 3 : 38.5g/100ml, Fe 2 (SO 4 ) 3 : 20g/100ml), when the temperature of the solution is kept at 25°C, the difference in solubility of the two components is greater than 18.5g/100ml, when the temperature is greater than 25°C, the solubility of the two components gradually decreases with the increase of temperature; When the temperature is less than 25°C, the solubility of the two components gradually becomes smaller as the temperature decreases.
  • the method of the present invention adopts the method of maintaining the temperature of the mixed solution to 10°C-55°C, preferably 20°C-30°C, and the solution concentration is maintained at 20g/ 100ml-30g/100ml separate iron sulfate from the mixed solution, and further crystallize them into aluminum sulfate, aluminum nitrate, iron sulfate, and iron nitrate products, or separate the aluminum sulfate solution and aluminum nitrate and iron nitrate from the iron sulfate
  • the mixed liquor becomes the mother liquor for subsequent processing.
  • the conversion liquid is subjected to ammonia metathesis.
  • the ammonia gas is passed into the aluminum sulfate solution or the mixed solution of aluminum nitrate and iron nitrate generated in the third embodiment for metathesis.
  • ammonia molecules dissolved in water ionize ammonium ions and hydroxide ions.
  • the weakly basic ammonium ions combine with strongly acidic sulfate ions or nitrate ions to form ammonium sulfate or ammonium nitrate, and hydroxide ions.
  • the mixed solution in the condenser to separate the precipitation of aluminum hydroxide or iron hydroxide from the ammonium sulfate or ammonium nitrate solution, aluminum hydroxide or iron hydroxide It is further processed into finished products.
  • the ammonium sulfate and ammonium nitrate solutions are heated and decomposed to drive out the ammonia molecules.
  • the clear liquid containing sulfuric acid or nitric acid is repeatedly implemented to absorb the aluminum oxide and iron oxide in the smoke and the ammonia molecules are dissolved.
  • the mixed solution continues to metathesize and circulate accordingly to achieve the extraction of aluminum oxide from the fly ash.
  • This method is realized by strong stirring and fusion of sodium hydroxide solution and silicon dioxide in a high-speed stirring reactor.
  • the silicon dioxide and sodium hydroxide are proportioned at a ratio of 1:1.33 (adjusted according to different product modulus requirements)
  • the stirring speed is maintained at a speed greater than 100r/sim to react for 40-60 minutes.
  • the sodium hydroxide in the kettle It is fused and transformed with silica in a forced contact environment.
  • the silica in the smoke is decomposed into fine particles of extremely fine particle size during the combustion of coal, the frequency of contact and collision with the sodium hydroxide solution increases under high-speed stirring, and the compound The reaction speed is accelerated, and the two components are converted into sodium metaaluminate after a combination time of less than 60 minutes. The process completes the recycling of more than 90% of solid pollutants.
  • a process for comprehensive recycling and utilization of pollutants in high-aluminum coal flue gas purification is based on the realization of flue gas desulfurization, denitrification, and dust removal through a dry-wet hybrid integrated flue gas purification device, combining various processes and technologies. Integrated removal of solid pollutants, liquid pollutants, and gaseous pollutants, and the use of the physical and chemical properties of each pollutant to reinforce each other, so that each component can play an advantage in mutual existence, decomposition, and purification, and finally achieve the purpose of waste treatment .

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Abstract

一种高铝煤烟气净化中污染物综合回收利用工艺，采用物理吸附法、化学吸附法脱除烟气中的SO 2；采用氧化和吸附法脱除烟气中的NOx；采用水溶浸渍法将两种吸附质脱附；通过脱附液与烟气混合转化吸收烟尘中的Al 2O 3\Fe 2O 3并转化为Al 2(SO 4) 3\Al(NO 3) 3\Fe(NO 3) 3\Al(NO 3) 3；根据各成分溶解度的差异采取分步结晶法将硫酸铝和硫酸铁分离；通过加氨复分解法将硫酸铝、硝酸铝分解为氢氧化铝、硫酸铵、硝酸铵；通过氢氧化钠液相融合法在高速搅拌反应釜内将提取铝、铁后排出的杂质进行再度吸收转化，使杂质中的二氧化硅与之融合转化成偏硅酸钠，以此完成粉煤灰最大化的回收利用。

Description

一种高铝煤烟气净化中污染物综合回收工艺 技术领域
本发明涉及大气环境治理领域，特别涉及燃煤锅炉使用高铝煤燃烧产生的气态污染物、液态污染物和固态污染物综合治理的工业烟气净化技术。
背景技术
我国高铝粉煤灰年排放量约2500万吨，累积堆存超过1亿吨，高铝粉煤灰大量堆存导致严重的大气、水体和土壤污染，由于高铝煤在地质年代里形成原因复杂，煤中的硫成分含量也相对较高，在燃烧过程中产生的二氧化硫随烟气排入大气被雨雪吸收形成酸雨降落地面，对人类健康以及地表植物、土壤造成危害。这种特殊的煤质结构，通过燃烧形成的气态污染和固态污染严重侵害着人类健康和生态环境，因此，燃烧高铝煤产生的污染物综合治理是一项有待开发的循环体系技术。
常规技术采用高效燃烧法将高铝煤充分燃烧，通过碱法、钙法或其他方法将高铝煤燃烧过程中产生的二氧化硫经转化脱除；将高铝粉煤灰收集堆存，再采用拜耳提取法、一步水热法、二步水热法从高铝粉煤灰里提取AL 2O 3。这些方法分步运行，不但增加了处理难度，而且使处理费用大幅度提高，导致高铝煤使用后的二次污染物增大，严重影响了高铝煤的资源化利用。
我国是一个铝矿资源极其贫乏的国家，高品位铝土矿对外依存度高，开发高铝粉煤灰提取氧化铝技术，不仅能够有效缓解高铝粉煤灰 堆存产生的环境污染问题，而且能够降低我国对高品位铝土矿的对外依存度。
内蒙古准格尔、土右、卓资山地区是我国特有的高铝煤炭资源富集地区，现已探明煤铝共存的煤炭资源储量500多亿吨，煤中氧化铝含量10％-13％，粉煤灰中氧化铝含量高达40％-55％，潜在高铝粉煤灰资源量150亿吨，远远高于我国探明铝土矿资源总储量。准格尔煤田年产1亿吨高铝煤，可产生3000万吨高铝粉煤灰，可提取氧化铝1200万吨，折合铝土矿量2500万吨，相当于一年进口量，已探明的准格尔高铝煤折合高铝粉煤灰储量达70亿吨，将其中的AL 2O 3全部提取，可使我国铝资源保障年限延长50-60年。
发明内容
本发明的提出，是对燃煤烟气净化技术的改进，特别是对高铝煤燃烧产生污染物治理及综合利用技术的创新。发明中采用物理吸附法、化学吸附法将烟气中的二氧化硫吸附脱除；采用氧化+吸附法将烟气中的氮氧化物脱除；采用水溶浸渍脱附法将两种吸附质分别脱除；通过脱附液与烟气气雾混合对流吸收法将烟尘中的三氧化二铝、三氧化二铁吸收转化为硫酸铝、硝酸铝和硫酸铁、硝酸铁；根据各成分溶解度的差异采取分步结晶法将硫酸铝和硫酸铁分离；通过加氨复分解法将硫酸铝、硝酸铝分解为氢氧化铝、硫酸铵、硝酸铵；通过循环利用法将氨、硫酸、硝酸反复使用使之成为该工艺连续提铝的周转载体，使粉煤灰中铝成分的提取轻松实现；通过氢氧化钠液相融合法在高速搅拌反应釜内将提取铝、铁后排出的杂质进行再度吸收转化，使杂质 中的二氧化硅与之融合转化成偏硅酸钠，以此完成粉煤灰最大化的回收利用。以本发明实现的一种高铝煤烟气净化中污染物综合回收工艺，在治理烟气污染物的同时将气态污染物、液态污染物、固态污染物通过各种技术的结合使其在相生相克中互存、分解、提纯，最终实现以废治废的目的。
根据本发明的一种实施方式，锅炉烟气首先经过间接换热器的热风装置，将自然风制成热风，再经过间接换热器的蒸发系统，在蒸发系统内先经过第一蒸发系统将脱附液浓缩，经过第二蒸发系统将合成液浓缩，经过第三蒸发系统将加氨复分解后的混合溶液蒸发浓缩并驱出其中的氨分子。
根据本发明的一种实施方式，选用经过负载离子改性了的活性炭制成吸附剂载体，将该载体制成使烟气在最小风阻下能够保持最大面积、最长时间与之接触的串绕式吸附净化载体，将吸附载体合理布局，组合成错格结构的烟气净化系统。在该系统中，烟气不断通过往复串绕与吸附剂接触，烟气中的二氧化硫分子因自身沸点高、活性强在接触中迅速被吸附，以此完成吸附净化过程中的脱硫。
根据本发明的一种实施方式，将开孔式泡沫玻璃制成一定规格的催化载体，将该载体安装于净化系统的氧化段，与串绕式吸附净化段组成复合式净化结构；通过喷淋方式浇注氧化剂，使氧化剂在流动中成为泡沫玻璃球壁的液膜，当烟气穿越催化载体时，烟气中的一氧化氮与球壁的氧化剂接触，迅速吸收其中的氧原子被氧化成二氧化氮，二氧化氮在穿越串绕式吸附系统时被吸附剂吸附，以此完成氧化+吸 附系统的脱硝。
根据本发明的一种实施方式，当吸附系统在吸附净化运行中达到饱和程度时，通过水蒸气溶解脱附法和/或热水溶解脱附法将吸附剂载体中的吸附质溶解脱附，使吸附质分子(SO 2、NO X)与水化合成稀硫酸、稀硝酸。
根据本发明的一种实施方式，将脱附液浓缩后在气雾对流转化净化系统内分别雾化，使稀硫酸雾液与烟气对流接触吸收烟尘中的三氧化二铝转化成硫酸铝，吸收三氧化二铁转化成硫酸铁；使稀硝酸雾液与烟气对流接触吸收烟尘中的三氧化二铝转化成硝酸铝，吸收三氧化二铁转化成硝酸铁；将混合液经澄清沉淀出烟尘中未转化的杂质，杂质中的二氧化硅经脱水后再与氢氧化钠在高速搅拌反应釜内融合制成偏铝酸钠；清液经浓缩后通过冷却结晶将硫酸铝与硫酸铁分离，进一步分别结晶制成硫酸铝、硫酸铁、硝酸铝、硝酸铁成品；或将分离出硫酸铁后的硫酸铝单质溶液或硝酸铝、硝酸铁混合溶液浓缩后成为后续处理的母液。
根据本发明的一种实施方式，将上一个方式生成的含硫酸铝或硝酸铝的母液与氨水混合进行复分解，根据化学反应原理，在酸性环境下，溶解在水中的氨分子电离出铵根离子和氢氧根离子，弱碱性的铵根离子与强酸性的硫酸根离子或硝酸根离子结合生成硫酸铵或硝酸铵，氢氧根离子与铝离子结合生成氢氧化铝；混合溶液在冷凝器内降温将低溶解度的氢氧化铝通过沉降分离法与硫酸铵或硝酸铵溶液分离，氢氧化铝经脱水、干燥制成成品；硫酸铵、硝酸铵溶液经加温分 解驱出氨分子，含硫酸或硝酸的清液重复实施上一个方式吸收烟尘中的三氧化二铝、三氧化二铁；氨分子溶于混合液持续复分解，依此循环以实现粉煤灰中三氧化二铝、三氧化二铁的提取。
实施本发明的方式
根据本发明的一种实施方式，本发明目的的实现是通过下述方式来完成的：
一、通过间接换热系统生产热风并浓缩脱附液。
锅炉烟气通过聚合，在前端风机推送力或后端引风机吸引力的作用下送入气液间接换热器，换热器分为两个单元，第一个单元是气气间接换热器，第二个单元是液气间接换热器，在第一个换热器内，风管横向排列，自然风在风机吹送力或引力的作用下在风管内流动，热烟气从管与管的空隙横向穿越，在穿越的同时与管内的自然风换热，自然风通过管壁的传热作用吸收烟气的热量并呈S形在换热器内蜿蜒前行，经多次重复受热后温度达到要求标准，在风机吹送下进入干燥系统。在第二个单元内，管道纵向排列，脱附液、分解液在管内通过管壁的传热向烟气吸收热量，高温烟气横向切入通过列管散失热量，脱附液、分解液在换热的作用下蒸发浓缩。根据工艺需求，该单元分为两段蒸氨系统和两段蒸发系统，两段蒸氨系统包括脱附液蒸氨、复分解液蒸氨，驱出的氨气通过逸氨通道进入吸附系统或加氨复分解系统；两段蒸发系统分为蒸氨后的脱附液蒸发段和蒸氨后的复分解液蒸发段，在蒸发过程中产生的水蒸汽通过蒸汽管道用于吸附流程中吸附质的脱附，浓缩液从底部放料口间断排出进入下一个流程。
二、通过干湿混合式脱硫脱硝装置首先完成对烟尘、硫氧化物和氮氧化物的脱除。
1、利用脱附液除尘并吸收烟尘中的三氧化二铝、三氧化二铁。
经换热后的烟气在前端风机的作用下吹入聚气仓聚集，在烟气分布器的分布下使气压均衡的上行至第一级水雾除尘段，后续流程生成的脱附液通过高压喷嘴雾化与上升的烟气产生对流接触，烟尘溶于脱附液并顺流至集液区，烟气与雾化了的脱附液在对流接触中，脱附液中的稀硫酸或稀硝酸吸收烟尘中的三氧化二铝和三氧化二铁，产生如下化学反应：3H 2SO 4+AL 2O 3＝AL 2(SO 4) 3+3H 2O；2AL 2O 3+12HNO 3＝4AL(NO 3) 3+6H 2O；3H 2SO 4+Fe 2O 3＝Fe 2(SO 4) 3+3H 2O；Fe 2O 3+6HNO 3＝2Fe(NO 3) 3+3H 2O.烟尘通过沉降法脱除，根据脱除效率确定水雾除尘段的节数。
该实施方式所述的烟气聚气仓，是装置底部倒椎体上半部分通过隔断封闭的内部周圈均布进风口的三角环形气仓，烟气从下部风口进入再通过周圈进风口进入装置。
该实施方式所述的烟气分布器是水雾除尘段底部按一定比例分部的若干个蘑菇帽布风器，下部的烟气从中心管进入蘑菇帽再从周圈出风管排出，其作用一方面是为了均布烟气，另一方面是为了避免上部的喷淋液流入下部装置。
2、通过错格式吸附净化方式完成初步脱硫脱硝。
经过若干节水雾除尘后的烟气进入错格式串绕吸附净化段，通过密布的净化器经中心筒穿过夹层内的吸附剂向外扩散，烟气在穿越吸 附剂(特制活性炭表面)做串绕式运动时，烟气中的水分子与活性炭表面的活性层产生复杂的电离反应生成羟基官能团(-OH)，即：H 2O→-OH *+H +，(*表示吸附态，-OH表示羟基官能团)，同时烟气中的氧分子也被活性炭表面的活化能催化分解成氧原子，即O 2→2O *。羟基官能团与氧原子的产生，给活性炭表面的活性中心生成了多位活性配合物，即：-OH *、O *，烟气中一氧化氮分子在多位活性配合物的作用下迅速得到氧原子而生成二氧化氮，即：NO+O *→NO 2。由于二氧化氮、二氧化硫分子的沸点高(NO 2＝21.1℃，SO2＝-10℃)，极性强，属酸性分子，又由于净化系统中的吸附剂是一种经过表面改性并具有碱性官能团表面吸附位的特制活性炭，因此当烟气穿越吸附层与吸附剂载体接触时双方产生酸碱亲和力而被迅速吸附，当吸附剂吸附了酸性分子后，吸附剂表面产生酸性官能团，又对碱性分子产生亲和力，因此，该实施方式通过蒸氨系统摄入碱性分子：NH 3→-NH 2 *+H +(-NH 2表示氨基官能团)。氨水在蒸氨器内受热分解：NH 3H 2O→NH 3+H 2O，氨分子随烟气进入净化系统，在穿越吸附净化层时受酸性官能团亲和力的作用被吸附剂迅速吸附：-OH *+M ++X -＝-OM *+H ++X -，碱性分子在吸附孔中覆盖了酸性分子，使吸附剂载体表面生成碱性官能团，碱性官能团对酸性分子产生亲和力，在亲和力的作用下迅速吸附酸性分子：-NH 2 *+H ++X -＝-NH 3X *，以此反复，使该系统的净化形成了酸碱分子的对叠吸附净化，以此实现氮氧化物与硫氧化物的迅速脱除。
烟气依照第一节串绕方式在装置主体内由下而上逐节穿行，上下两节内的净化筒错格分布，在穿行过程中通过密布的净化器做相同的 串绕式吸附，烟气中的SO 2由于极性、沸点、活性高于其他分子而被优先吸附，部分NO在吸附层表面活性配合物的作用下氧化成NO 2，烟气通过若干节叠置净化层的净化达到第一级净化目的。
3、通过再氧化+再吸附实现氮氧化物的最大化脱除。
烟气经过第一级净化流程后，其中的大部分有害成分被脱除，由于氮氧化物的脱除是一个复杂的过程，一氧化氮氧化成二氧化氮，二氧化氮在与水或吸附剂接触时又会有小部分还原成一氧化氮，因此需要采取再氧化再吸附来完成对氮氧化物的彻底脱除，其方法是将第一级净化后的尾气再次通过外围分路净化器的分节串绕式吸附净化系统进行再净化，其过程是通过再氧化和再吸附实现的。所述的再氧化是将烟气通入氧化箱，氧化箱内按一定规格安装着开孔式泡沫玻璃制成的催化载体，氧化段与串绕式吸附净化段组成复合式净化结构。在氧化段内通过喷淋方式向催化载体浇注氧化剂，氧化剂选用次氯酸钠、亚氯酸钠等。氧化剂在催化载体内部流动中成为泡沫玻璃球壁的液膜，当烟气穿越催化载体时，烟气中的一氧化氮与球壁的氧化剂接触，迅速吸收其中的氧原子被氧化成二氧化氮，二氧化氮在穿越串绕式吸附系统时被吸附剂吸附，以此完成该工艺最大化的脱硝。
当吸附剂吸附了足量的分子后，吸附效率开始下降，吸附逐渐进入饱和状态，需要开启脱附流程。
4、通过水溶解法完成对吸附质的脱附。
该工艺采用的脱附分为两种方式，一是通过气态水分子渗透溶解分路净化系统的吸附质，二是通过液态水分子团冲淋溶解主体叠置净 化系统内的吸附质。水蒸气经过蒸汽分配器交替通入分路净化器，在其扩散力的作用下浸入活性炭的吸附孔内，与吸附质溶合转化，使新生的分子在生成过程中产生膨胀力的作用下将自身推出吸附孔再溶解于水分子团，即：SO 2 *+O *＝SO 3 *，H 2O+SO 3 *＝H 2SO 4，H 2SO 4+2NH 3＝(NH 4) 2SO 4，2NH 3+2NO 2+H 2O→NH 4NO 3+NH 4NO 2，NH 4NO 2→N 2+2H 2O.以此实现脱附并生成硝硫基铵盐；二是将液态水经过高压水管的输送分别打入主体各节净化层，通过脱附环管的喷射眼向对应的净化单元喷洒，依照上述原理将吸附质脱附。
三、将硫酸铁、硝酸铁从混合液中分离。
通过分节气雾对流混合式吸收转化(稀硫酸、稀硝酸分别在不同的气雾对流吸收段内单独进行)，雾液中的稀硫酸吸收氧化铝、氧化铁转化成硫酸铝、硫酸铁，稀硝酸吸收氧化铝、氧化铁转化成硝酸铝硝酸铁，为了尽量使再生物纯度提高，本发明采用溶解度差异分离法将硫酸铁从硫酸铁与硫酸铝的混合液中分离，本方法是通过将混合液降温至25℃左右来实现两种成分分离的(根据硫酸铝、硫酸铁溶液在25℃时的溶解度观察：AL 2(SO 4) 3：38.5g/100ml，Fe 2(SO 4) 3：20g/100ml)，当溶液温度保持到25℃时，两种成分的溶解度差异大于18.5g/100ml，当温度大于25℃时，两种成分的溶解度随温度的升高而逐渐变小；当温度小于25℃时，两种成分的溶解度随温度的降低而逐渐变小，因此本发明方法采用将混合溶液的温度保持到10℃-55℃，优选20℃-30℃，溶液浓度保持的20g/100ml-30g/100ml将硫酸铁从混合溶液中分离出来，进一步分别 结晶制成硫酸铝、硝酸铝、硫酸铁、硝酸铁成品，或将分离出硫酸铁后的硫酸铝溶液及硝酸铝、硝酸铁混合液成为后续处理的母液。
二、对转化液进行加氨复分解。
根据化学反应原理，将氨气通入实施方式三生成的硫酸铝溶液或硝酸铝、硝酸铁混合液进行复分解。在酸性环境下，溶解在水中的氨分子电离出铵根离子和氢氧根离子，弱碱性的铵根离子与强酸性的硫酸根离子或硝酸根离子结合生成硫酸铵或硝酸铵，氢氧根离子与铝离子、铁离子结合生成氢氧化铝、氢氧化铁，即：AL 2(SO 4) 3+6NH 3.H 2O＝2AL(OH) 3+3(NH 4) 2SO 4；AL(NO 3) 3+3NH 3H 2O＝3NH 4NO 3+AL(OH) 3；Fe 2O 3+6HNO 3＝2Fe(NO 3) 3+3H 2O；Fe(NO 3) 3+3NH 3H 2O＝3NH 4NO 3+Fe(OH) 3.将混合溶液在冷凝器内降温将氢氧化铝或氢氧化铁沉淀与硫酸铵或硝酸铵溶液分离，氢氧化铝或氢氧化铁进一步加工制成成品，硫酸铵、硝酸铵溶液经加温分解驱出氨分子，含硫酸或硝酸的清液重复实施上一个方式吸收烟尘中的三氧化二铝、三氧化二铁，氨分子溶于混合液持续复分解，依此循环以实现粉煤灰中三氧化二铝的提取。
五、从提取铝、铁后的粉煤灰杂质中提取二氧化硅。
该方式是通过氢氧化钠溶液与二氧化硅在高速搅拌反应釜内强力搅拌融合实现的。根据化学反应式：2NaOH+SIO 2＝NaSIO 3+H 2O的化学反应原理，将二氧化硅与氢氧化钠按比例1∶1.33配量，(根据产物模数要求的不同另行调整)，将混合液经澄清后沉淀出的烟尘杂质与氢氧化钠在高速搅拌反应釜内混合，通过搅拌方式，使搅拌速度保持 在大于100r/sim的转速下反应40-60分钟，釜内的氢氧化钠与二氧化硅在强制接触的环境下融合转化，由于烟尘中的二氧化硅在煤炭燃烧过程中分解成粒度极细的微粉，在高速搅拌状态下与氢氧化钠溶液的接触碰撞频率提高，化合反应速度加快，经过小于60分钟的化合时间使两种成分转化为偏铝酸钠，该工艺完成了大于90％固态污染物的回收利用。
综上所述，一种高铝煤烟气净化中污染物综合回收利用工艺，通过干湿混合式一体化烟气净化装置，结合各种工艺、技术，在实现烟气脱硫脱硝除尘的基础上将固态污染物、液态污染物、气态污染物一体化脱除，并利用各污染物相生相克的物理化学性质，使各成分在互存、分解、提纯中发挥优势，最终实现以废治废的目的。

Claims (10)

  1. 一种高铝煤烟气净化中污染物综合回收利用工艺，该工艺包括：a、通过对烟气的余热利用生产热风、蒸发浓缩脱附液、分解液；b、通过物理吸附、化学吸附脱除烟气中的硫氧化物、氮氧化物；c、通过水溶法脱除吸附质；d、通过脱附液在气雾对流式除尘的过程中吸收烟尘中的氧化铝、氧化铁；e、通过再氧化+再吸附使脱硝效果最大化；f、通过溶解度的差异将硫酸铝和硫酸铁分离；g、通过对硫酸铝、硝酸铝加氨复分解制取氢氧化铝；h、通过氢氧化钠在高速搅拌反应釜内与二氧化硅融合制取偏硅酸钠；r、该工艺同样适合于任何煤质燃烧产生的烟气净化。
  2. 根据权利要求1所述的一种高铝煤烟气净化中污染物综合回收利用工艺，所述的余热利用是通过间接换热系统生产热风并浓缩脱附液；
    所述的生产热风是锅炉烟气在第一单元内进行气气换热得到热风；其特征是：在气气换热器内，风管横向排列，自然风在风机吹送力或引力的作用下在风管内流动，热烟气从管与管的空隙横向穿越，在穿越的同时与管内的自然风换热，自然风通过管壁的传热作用吸收烟气的热量并呈S形在换热器内蜿蜒前行，经多次重复受热后温度达到要求标准；
    所述的浓缩脱附液，是锅炉烟气在换热器第二个单元内经过气液换热以实现脱附液、分解液浓缩；其特征是在气液换热器内管道纵向排列，脱附液、分解液在管内通过管壁的传热向烟气吸收热量，高温 烟气横向切入通过列管散失热量，脱附液、分解液在换热的作用下蒸发浓缩；在蒸发过程中产生的水蒸汽或氨气通过相应管道通入吸附流程中吸附质的脱附或分解系统，浓缩液从底部放料口间断排出进入下一个流程。
  3. 根据权利要求1所述的一种高铝煤烟气净化中污染物综合回收利用工艺，所述的通过物理吸附、化学吸附脱除烟气中的硫氧化物、氮氧化物，是通过两个方式实现的，其一是通过错格式吸附净化方式完成初步脱硫脱硝；其特征是将烟气送入错格式串绕吸附净化段，通过密布的净化器经中心筒穿过夹层内的吸附剂向外扩散，烟气在穿越吸附剂(特制活性炭表面)做串绕式运动时，烟气中的水分子与活性炭表面的活性层产生复杂的电离反应生成羟基官能团(-OH)，即：H 2O→-OH *+H +，(*表示吸附态，-OH表示羟基官能团)，同时烟气中的氧分子也被活性炭表面的活化能催化分解成氧原子，即O 2→2O *；羟基官能团与氧原子的产生，给活性炭表面的活性中心生成了多位活性配合物，即：-OH *、O *，烟气中一氧化氮分子在多位活性配合物的作用下迅速得到氧原子而生成二氧化氮，即：NO+O *→NO 2；由于二氧化氮、二氧化硫分子的沸点高(NO 2＝21.1℃，SO2＝-10℃)，极性强，属酸性分子，又由于净化系统中的吸附剂是一种经过表面改性并具有碱性官能团表面吸附位的特制活性炭，因此当烟气穿越吸附层与吸附剂载体接触时双方产生酸碱亲和力而被迅速吸附，当吸附剂吸附了酸性分子后，吸附剂表面产生酸性官能团，又对碱性分子产生亲和力，因此，该实施方式通过蒸氨系统摄入碱性分子：NH 3→-NH 2 *+H +(-NH 2表示氨 基官能团)；氨水在蒸氨器内受热分解：NH 3H 2O→NH 3+H 2O，氨分子随烟气进入净化系统，在穿越吸附净化层时受酸性官能团亲和力的作用被吸附剂迅速吸附：-OH *+M ++X -＝-OM *+H ++X -，碱性分子在吸附孔中覆盖了酸性分子，使吸附剂载体表面生成碱性官能团，碱性官能团对酸性分子产生亲和力，在亲和力的作用下迅速吸附酸性分子：-NH 2 *+H ++X -＝-NH 3X *，以此反复，使该系统的净化形成了酸碱分子的对叠吸附净化，以此实现氮氧化物与硫氧化物在化学吸附下的迅速脱除；烟气依照第一节串绕方式在装置主体内由下而上逐节穿行，上下两节内的净化筒错格分布，在穿行过程中通过密布的净化器做相同的串绕式吸附，烟气中的SO 2由于极性、沸点、活性高于其他分子而被优先吸附(物理吸附)，部分NO在吸附层表面活性配合物的作用下氧化成NO 2，烟气通过若干节叠置净化层的净化达到第一级净化目的；
    其二是通过再氧化+再吸附实现氮氧化物的最大化脱除，所述的再氧化是将烟气通入氧化箱，氧化箱内按一定规格安装着开孔式泡沫玻璃制成的催化载体，氧化段与串绕式吸附净化段组成复合式净化结构；
    所述的再氧化实现的方式是：在再氧化段内通过喷淋方式向催化载体浇注氧化剂，氧化剂在催化载体内部流动中成为泡沫玻璃球壁的液膜，当烟气穿越催化载体时，烟气中的一氧化氮与球壁的氧化剂接触，迅速吸收其中的氧原子被氧化成二氧化氮，二氧化氮在穿越串绕式吸附系统时被吸附剂吸附(物理吸附)；
    所述的氧化剂是包括但不限于次氯酸钠、亚氯酸钠、稀硝酸等， 其使用浓度范围是5％-25％。
  4. 根据权利要求1所述的一种高铝煤烟气净化中污染物综合回收利用工艺，所述的通过水溶法脱除吸附质，一是通过气态水分子渗透溶解分路净化系统的吸附质，二是通过液态水分子团冲淋溶解主体叠置净化系统内的吸附质；其特征是：水蒸气经过蒸汽分配器交替通入分路净化器，在其扩散力的作用下浸入活性炭的吸附孔内，与吸附质溶合转化，使新生的分子在生成过程中产生膨胀力的作用下将自身推出吸附孔再溶解于水分子团，即：SO 2 *+O *＝SO 3 *，H 2O+SO 3 *＝H 2SO 4，H 2SO 4+2NH 3＝(NH 4) 2SO 4，2NH 3+2NO 2+H 2O→NH 4NO 3+NH 4NO 2，NH 4NO 2→N 2+2H 2O，以此实现脱附并生成硝硫基铵盐；二是将液态水经过高压水管的输送分别打入主体各节净化层，通过脱附环管的喷射眼向对应的净化单元喷洒，依照上述原理将吸附质脱附。
  5. 根据权利要求1所述的一种高铝煤烟气净化中污染物综合回收利用工艺，所述的通过脱附液在气雾对流式除尘的过程中吸收烟尘中的氧化铝、氧化铁，是通过气液对流吸收法在气雾对流除尘段实现的，其方式是：烟气通过烟气分布器的分布使气压均衡的上行至第一级气雾对流除尘段与高压喷嘴雾化的脱附液产生对流接触，烟尘溶于脱附液并顺流至集液区，烟气与雾化了的脱附液在对流接触中，脱附液中的稀硫酸或稀硝酸吸收烟尘中的三氧化二铝和三氧化二铁，产生如下化学反应：3H 2SO 4+AL 2O 3＝AL 2(SO 4) 3+3H 2O；2AL 2O 3+12HNO 3＝4AL(NO 3) 3+6H 2O；3H 2SO 4+Fe 2O 3＝Fe 2(SO 4) 3+3H 2O；3HNO 3+Fe 2O 3＝2Fe(NO 3) 3+3H 2O。
  6. 根据权利要求1所述的一种高铝煤烟气净化中污染物综合回收利用工艺，所述的气雾对流除尘段是一体化净化装置中实现湿式除尘并吸收烟尘中有效成分的由若干段组成的一个系统，在该系统内，不同成分的脱附液吸收烟尘内的有效成分分别运行；该装置的结构特征是：顶部是高压雾化装置，底部是烟气分布系统，烟气通过底部的烟气分布系统上行与顶部雾化液滴作对流接触运动；烟气分布系统的特征是：气雾对流除尘段底盘上按一定比例分布着若干个蘑菇帽布风器，下部的烟气从中心管进入蘑菇帽再从周圈出风管排出，其作用一方面是为了均布烟气，另一方面是为了避免上部的喷淋液流入下部装置。
  7. 根据权利要求1所述的一种高铝煤烟气净化中污染物综合回收利用工艺，所述的通过溶解度的差异将硫酸铝和硫酸铁分离，其目的是为了尽量使再生物纯度提高，采取的方法是采用溶解度差异分离法将硫酸铁从硫酸铁与硫酸铝的混合液中分离；本方法是通过将混合液降温至10℃-55℃来实现两种成分分离的，根据硫酸铝、硫酸铁溶液在25℃时的溶解度观察：AL 2(SO 4) 3：38.5g/100ml，Fe 2(SO 4) 3：20g/100ml，两种成分在溶液中溶解度的变化特征是：当溶液温度保持到25℃时，两种成分的溶解度差异大于18.5g/100ml，当温度大于25℃时，两种成分的溶解度随温度的升高而逐渐变小，当温度小于25℃时，两种成分的溶解度随温度的降低而逐渐变小，因此本发明方法采用将混合溶液的温度保持到10℃-55℃，优选20℃-30℃，将混合溶液的浓度保持在20g/100ml-25g/ml，以此 将硫酸铁从混合溶液中分离出来，进一步分别结晶制成硫酸铝、硝酸铝、硫酸铁、硝酸铁成品；或将分离出硫酸铁后的硫酸铝溶液及硝酸铝、硝酸铁混合液成为复分解处理的母液。
  8. 根据权利要求书1所述的一种高铝煤烟气净化中污染物综合回收利用工艺，所述的通过对硫酸铝、硝酸铝加氨复分解制取氢氧化铝的依据是根据化学反应原理：AL 2(SO 4) 3+6NH 3.H 2O＝2AL(OH) 3+3(NH 4) 2SO 4；AL(NO 3) 3+3NH 3H 2O＝3NH 4NO 3+AL(OH) 3；Fe 2O 3+6HNO 3＝2Fe(NO 3) 3+3H 2O；Fe(NO 3) 3+3NH 3H 2O＝3NH 4NO 3+Fe(OH) 3；其方法是将间接换热器蒸氨系统产生的氨气通入前面流程生成的硫酸铝溶液或硝酸铝、硝酸铁混合液中进行复分解；在酸性环境下，溶解在水中的氨分子电离出铵根离子和氢氧根离子，弱碱性的铵根离子与强酸性的硫酸根离子或硝酸根离子结合生成硫酸铵或硝酸铵，氢氧根离子与铝离子、铁离子结合生成氢氧化铝、氢氧化铁；
    进一步的将混合溶液在冷凝器内降温将氢氧化铝或氢氧化铁沉淀与硫酸铵或硝酸铵溶液分离；更进一步的将氢氧化铝或氢氧化铁加工制成成品；
    将硫酸铵、硝酸铵溶液经加温分解驱出氨分子，含硫酸或硝酸的清液重复实施气雾对流方式吸收烟尘中的三氧化二铝、三氧化二铁；氨分子溶于混合液持续复分解，依此循环以实现粉煤灰中三氧化二铝的提取。
  9. 根据权利要求书1所述的一种高铝煤烟气净化中污染物综合 回收利用工艺，所述的通过氢氧化钠在高速搅拌反应釜内与二氧化硅融合制取偏硅酸钠，是通过氢氧化钠溶液与二氧化硅在高速搅拌反应釜内强力搅拌融合实现的，其依据是根据化学反应式：2NaOH+SIO2＝NaSIO3+H2O的化学反应原理；其方法是将二氧化硅与氢氧化钠按比例1∶1.33配量，(根据产物模数要求的不同另行调整)；其步骤是将混合液经澄清后沉淀出的烟尘杂质与氢氧化钠在高速搅拌反应釜内混合，通过搅拌方式，使搅拌速度保持在大于100r/sim的转速下反应40-60分钟，釜内的氢氧化钠与二氧化硅在强制接触的环境下融合转化成偏铝酸钠。
  10. 根据权利要求1所述的一种高铝煤烟气净化中污染物综合回收利用工艺，该工艺同样适合于任何燃煤产生的烟气净化。
PCT/CN2019/000165 2019-04-08 2019-08-21 一种高铝煤烟气净化中污染物综合回收工艺 WO2020206568A1 (zh)

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