Comprehensive utilization major cycle process in cooperative treatment of industrial flue gas pollutants

Abstract

The invention relates to a comprehensive utilization major cycle process in cooperative treatment of industrial flue gas pollutants, which comprises the following steps: removing SO2 and NOx in flue gas by adopting an adsorption method, and desorbing SO2 and NOx by adopting a water solution method to generate sulfuric acid and nitric acid; sulfuric acid reacts with sodium chloride to produce hydrochloric acid; sulfuric acid, nitric acid and hydrochloric acid are combined into a composite acid solvent, the solvent dissolves aluminum oxide in the fly ash to be converted into polybasic acid aluminum, the polybasic acid aluminum is subjected to ammonification decomposition into aluminum hydroxide and composite acid ammonium, the composite acid ammonium reacts with calcium carbonate to generate NH3, CO2 and polybasic acid calcium, and the polybasic acid calcium reacts with sodium sulfate to generate nano calcium sulfate; the method comprises the following steps: reacting silicon dioxide with sodium hydroxide to generate sodium silicate, reacting sodium silicate with sodium bicarbonate to generate silicic acid and sodium carbonate, reacting sodium carbonate with calcium hydroxide to generate calcium carbonate and sodium hydroxide, and mixing multi-element metal oxide separated from aluminum and silicon extraction with silicon dioxide and aluminum hydroxide which are separated and carried to prepare a multi-element cation molecular sieve; and comprehensive utilization and large circulation of the flue gas pollutants are realized through the synergistic effect of the pollutants.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection technology, and in particular to a large-scale circulation process for comprehensive utilization in the coordinated treatment of industrial flue gas pollutants. Background Art

[0002] Industrial flue gas treatment, including desulfurization, denitrification, decarbonization and dust removal of coal-fired flue gas, currently mostly adopts the method of single step-by-step treatment. Desulfurization generally adopts the limestone-gypsum method, denitrification adopts catalytic reduction method or non-catalytic reduction method, and dust removal adopts bag dust removal method or electrostatic precipitator method. Although there are many technologies for decarbonization, most of them are used for small emission control in high-concentration chemical exhaust gas and steel smelting and non-ferrous metal smelting fields. There is no large-scale application case for the removal of carbon dioxide in coal-fired flue gas.

[0003] The above process is used to treat coal-fired flue gas. While removing the pollutants in the flue gas, there are still the following disadvantages:

[0004] Disadvantages of limestone-gypsum desulfurization: 1. Calcium carbonate is used as a desulfurizer, which releases almost the same amount of carbon dioxide while absorbing sulfur dioxide in the flue gas; 2. Adding a desulfurizer not only increases the difficulty of operation, but also increases the operating cost; 3. During desulfurization, a large amount of water mist containing calcium carbonate and calcium sulfate is emitted into the air, causing secondary pollution.

[0005] Disadvantages of catalytic reduction and non-catalytic reduction denitrification methods: 1. Strong selectivity for flue gas temperature; 2. High cost of using reducing agent; 3. Reducing agent ammonia is easily emitted with flue gas, causing air pollution.

[0006] Disadvantages of bag dust removal and electrostatic precipitator: 1. High operating costs; 2. The intercepted and recovered fly ash is difficult to handle, and landfill not only occupies land and easily causes secondary pollution, but also wastes available resources.

[0007] At present, although great results have been achieved in the treatment of coal-fired flue gas, in terms of treatment methods, desulfurization, denitrification, decarbonization and dust removal are operated separately, which not only occupies a large area of ​​land, complicates the treatment process and increases the operating cost, but also causes waste of resources and energy by adding intermediates for removing pollutants. In addition, while treating one pollutant, another pollutant is produced, turning pollutants that should have generated greater added value into waste due to improper treatment.

[0008] Mixed salts are produced in the wastewater treatment process of coal chemical and coal-fired enterprises. Because they contain multiple components and carry trace amounts of heavy metal elements, they can neither be used in industrial production nor discarded. As a hazardous waste pollutant, they are difficult to treat. Decomposing and utilizing them separately can achieve both hazardous waste treatment and valuable utilization. This is a treatment measure that kills two birds with one stone.

[0009] At present, my country is in a new period of transformation and leapfrog development, and circular development and sustainable development have become the general tone of progress. The degree of comprehensive utilization of resources is an important indicator of the degree of human civilization and the level of scientific and technological development. If flue gas pollutants are removed in an integrated manner, desulfurization, denitrification, decarbonization, dust removal, and miscellaneous salt treatment will produce a synergistic effect of waste treatment in the treatment process, which will not only achieve pollutant treatment, but also utilize pollutants as resources in the treatment process to form a circular process and circular industrial chain, and also tap into huge hidden resources, turning harm into benefit and waste into treasure, thereby achieving sustainable development. Summary of the invention

[0010] The invention is an innovation and improvement in the treatment of coal-fired flue gas pollutants. The invention adopts an adsorption method to remove sulfur dioxide from the flue gas, an oxidation + adsorption method to remove nitrogen oxides in the flue gas after desulfurization, and an aqueous desorption method to desorb adsorbent sulfur dioxide and nitrogen dioxide and generate sulfuric acid and nitric acid; the dilute acid desorption liquid is made into a dust removal solvent. In order to expand the scope of comprehensive utilization of waste, hazardous waste salts are used as the main raw materials for flue gas decarbonization. The sodium chloride in the salts is combined with carbon dioxide through the ammonia-soda method to produce sodium bicarbonate while removing carbon dioxide from the flue gas, and the derivative ammonium chloride and the backward-generated calcium carbonate are reacted through double decomposition to produce ammonia and carbon dioxide; sodium chloride is replaced by the reaction of sodium sulfate and calcium chloride, and hydrogen chloride is produced by double decomposition reaction of sulfuric acid and sodium chloride. The hydrogen chloride is introduced into the flue gas dust removal system and hydrolyzed to produce hydrochloric acid; sulfuric acid, nitric acid and hydrochloric acid are combined into a polybasic composite acid solvent with aqua regia effect, and the ability to dissolve alumina in fly ash is enhanced by the polybasic composite acid solvent; aluminum oxide in fly ash is dissolved and converted into polybasic aluminum acid in a multi-stage aluminum dissolving reactor, so that the flue gas reaches the near-zero emission standard after integrated purification and is discharged.

[0011] The above-mentioned multi-stage aluminum dissolution process is to filter part of the polyacid aluminum converted by the first-stage dissolution through a filter press facility, separate the liquid phase of the polyacid aluminum from the filter cake, remix the solid phase of the filter cake with the continuously produced composite polyacid solvent, and repeat the first-stage aluminum dissolution process in the next-stage aluminum dissolution reactor. The filter cake is repeatedly dissolved, filtered, and solid-liquid separated again until the aluminum oxide in the filter cake is extracted to the maximum extent.

[0012] In the displacement reactor, polyacid aluminum is decomposed into aluminum hydroxide and ammonium sulfate, ammonium nitrate and ammonium chloride by adding ammonia. Aluminum hydroxide is separated by sedimentation, dehydrated and dried to be a finished product. The composite ammonium acid reacts with calcium carbonate generated in the backward causticizing reaction process in the double decomposition reaction system to generate ammonia, carbon dioxide and calcium sulfate, calcium chloride and calcium nitrate. Ammonia and carbon dioxide are recycled in the ammonia-soda process for alkali production. Calcium chloride and calcium nitrate react with sodium sulfate to generate calcium sulfate, sodium chloride and sodium nitrate. Sodium chloride is recycled in the ammonia-soda process for alkali production. Sodium nitrate is extracted by attached crystallization to be a finished product. Calcium sulfate generated in each process is made into nano calcium powder.

[0013] The main component of the filter cake filtered out after multi-stage aluminum dissolution is silicon dioxide. The silicon dioxide is mixed with the sodium hydroxide produced in the backward process in a liquid phase melting reactor, and sodium silicate is generated through high-temperature and high-speed stirring reaction. Sodium bicarbonate generated in the forward process is added to the sodium silicate solution, and silicic acid and sodium carbonate are replaced through ion exchange and hydrothermal synthesis reaction. The silicic acid is dried to produce silicon dioxide products. Sodium carbonate reacts with calcium hydroxide in a causticizing reactor to produce calcium carbonate and sodium hydroxide. Calcium carbonate is recycled in the forward process, and sodium hydroxide is recycled for liquid phase melting with silicon dioxide; the impurity multi-metal oxides separated by aluminum and silicon extraction and impure salt treatment are mixed with the separated silicon dioxide and aluminum hydroxide to form a multi-cation molecular sieve.

[0014] The large-cycle process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants achieved by the present invention, which not only realizes the integration of desulfurization, denitrification, decarbonization and dust removal, but also produces a synergistic effect in the joint desulfurization, turning pollutants into benefits and generating huge added value, thereby achieving the following purposes: 1. Desulfurization and denitrification by adsorption, while completing flue gas purification, the derivatives of sulfuric acid and nitric acid are used to form a composite acid; 2. The derivative hydrochloric acid produced by desulfurization, denitrification and sodium chloride replacement reaction is combined to form a polybasic composite acid, so that it produces an aqua regia effect in the aluminum dissolved in fly ash; 3. The aluminum extraction in fly ash is maximized by multi-stage aluminum extraction of polybasic composite acids; 4. By extracting sodium chloride from miscellaneous salts, sodium chloride is used to achieve flue gas decarbonization under the intervention of ammonia and the resultant sodium bicarbonate is used for ion exchange of sodium silicate; 5. Aluminoferrite is separated by solubility difference separation method, so that the removal of iron oxide is easily achieved; 6. Hydrogen and oxygen are replaced from polybasic aluminum by adding ammonia to the polybasic aluminum acid for double decomposition. 7. Separate the impure metal ions mixed in aluminum hydroxide by density difference separation method, so that the purity of the finished product can be further improved; 8. Produce ammonia and carbon dioxide for alkali production by double decomposition of ammonium sulfate, ammonium nitrate, ammonium chloride and calcium carbonate; 9. React polyacid calcium with sodium sulfate to obtain nano calcium sulfate while absorbing impurities of miscellaneous salts; 10. Dissolve and convert the silicon dioxide in the aluminum extraction residue to sodium silicate by sodium hydroxide, so that liquid phase melting reaction can be realized; 11. React the sodium silicate solution with sodium bicarbonate to generate silicic acid and sodium carbonate, so as to achieve the purpose of silicon extraction from fly ash while realizing the coordinated treatment of ammonia alkali method and fly ash; 12. Causticize the sodium carbonate solution with calcium hydroxide to produce sodium hydroxide, a raw material for silicon dissolution, and calcium carbonate, a by-product, so that the silicon dissolution process forms a cycle; 13. Mix the impure polymetallic oxides with the separated silicon dioxide and aluminum hydroxide to form a polycation molecular sieve, so that the waste residue in the process can be used at a high value.

[0015] To this end, the present invention provides a large-cycle process for comprehensive utilization in the coordinated treatment of industrial flue gas pollutants, which process includes: a. mixing sulfuric acid generated by desulfurization in the subsequent step b, nitric acid generated by denitrification in the step c, and hydrochloric acid generated by the double replacement reaction of sodium chloride in the step i to prepare a flue gas dust removal solvent, removing dust through a multi-component composite acid solvent, and producing an aqua regia effect in fly ash dissolved aluminum; b. removing sulfur dioxide from the flue gas after dust removal by an adsorption method; c. removing nitrogen oxides from the flue gas after desulfurization by an oxidation + adsorption method; d. desorbing sulfur dioxide and nitrogen dioxide in the adsorbent by a water-soluble desorption method to generate sulfuric acid and nitric acid; e. In the aluminum reactor, the aluminum oxide in the fly ash is dissolved and converted into polyacid aluminum; f. The impurity salt is dissolved and the impurity component sodium sulfate is separated by the attached crystallization separation method, so that the solution becomes a mother liquor with sodium chloride as the main component; i. Through the ammonia-alkali process, the sodium chloride solution is subjected to the intervention of ammonia gas through ammoniation and carbonation reactions to achieve flue gas decarbonization and the resulting sodium bicarbonate is used for ion exchange of sodium silicate; h. Aluminoferrite is separated by solubility difference separation method; i. The hydrogen chloride generated by the double replacement reaction of sodium chloride and sulfuric acid is introduced into step a, hydrolyzed to generate hydrochloric acid and added to the composite acid solution of step e along with the dust removal slurry; g. In the replacement system, aluminum hydroxide, iron hydroxide and ammonium polyacid are replaced by adding ammonia to the polyacid aluminum and the polyacid iron respectively; k. Impurity metal ions mixed in aluminum hydroxide are separated by density difference separation method; l. Ammonium polyacid and calcium carbonate generated by causticizing reaction in step n are subjected to double decomposition reaction to produce ammonia and carbon dioxide, and ammonia and carbon dioxide are recycled for alkali production in step j by ammonia-alkali method; m. Sodium sulfate generated in step f and step i is subjected to double replacement reaction with calcium chloride and calcium nitrate generated in step l to produce calcium sulfate, sodium chloride and sodium nitrate; n. Silicon dioxide and sodium hydroxide are dissolved in liquid phase o, adding sodium bicarbonate generated in the forward process to the sodium silicate solution, replacing silicon dioxide and sodium carbonate through ion exchange and hydrothermal synthesis reaction; p, removing impurities from silicon dioxide by acid washing and water washing to optimize the purity of silicon dioxide; q, reacting sodium carbonate with calcium hydroxide in a causticizing reactor to produce calcium carbonate and sodium hydroxide; r, mixing the impurity metal ions separated in step k and the multi-metal oxides obtained by acid washing and water washing in step p with the entrained silicon dioxide and aluminum hydroxide to prepare a multi-cation molecular sieve.

[0016] As shown in (Figure 2), according to one embodiment of the present invention, in step a, sulfuric acid generated by desulfurization in the subsequent step b, nitric acid generated by denitrification in step c, and hydrochloric acid produced by hydrolysis of hydrogen chloride produced by double replacement reaction of sodium chloride and sulfuric acid in step i are mixed to form a dust removal composite solvent and introduced into the flue gas dust removal system, so that the dust is removed by the multi-composite acid solvent, and an aqua regia effect is produced in the fly ash dissolved aluminum.

[0017] According to one embodiment of the present invention, the flue gas after dust removal in step a is sent into a multi-integrated desulfurization purification device under the action of a fan, and after step b, the desulfurization system contacts the adsorbent in the adsorption filter element in a series flow state, and the sulfur dioxide in the flue gas is adsorbed by the adsorbent, and the flue gas is desulfurized.

[0018] According to one embodiment of the present invention, the flue gas that has completed desulfurization in step b enters the denitrification system of step c under the blowing of a fan, first passes through a bubbling conversion system or an aerosol convection conversion system, and enters a recoil-type sleeve bubbler or an aerosol convection converter under a certain wind pressure, so that the flue gas is in gas-liquid contact with a solvent to which an oxidant is added, and the oxidant oxidizes the nitric oxide in the flue gas into nitrogen dioxide, and then the nitrogen dioxide is adsorbed by an adsorption method.

[0019] According to one embodiment of the present invention, when the sulfur dioxide adsorbed by the desulfurization system in step b or the nitrogen dioxide adsorbed by the denitrification system in step c reaches adsorption saturation, the two adsorbates are desorbed by a water-soluble impregnation method in step d, the sulfur dioxide is desorbed to generate sulfuric acid, and the nitrogen dioxide is desorbed to generate nitric acid.

[0020] According to one embodiment of the present invention, the sulfuric acid and nitric acid generated in step b and step c are mixed with the hydrochloric acid generated by hydrolysis of the hydrogen chloride produced in step i to form a composite acid, and the composite acid is used for dust removal in step a. The polybasic composite acid with aqua regia effect composed of sulfuric acid, nitric acid and hydrochloric acid is used to dissolve the alumina in the fly ash through a multi-stage aluminum dissolving converter in step e to generate polyacid aluminum.

[0021] This embodiment further includes that the multi-stage aluminum dissolution process is to filter part of the polyacid aluminum converted by the first-stage dissolution through a filter press facility to separate the liquid phase of the polyacid aluminum from the filter cake, and the polyacid aluminum enters the step g replacement reaction system, and the solid phase of the filter cake is mixed again with the subsequently continuously produced composite polyacid solvent, and the first-stage aluminum dissolution process is repeated in the next-stage aluminum dissolution reactor, and the filter cake is repeatedly dissolved, filtered, and solid-liquid separated until the aluminum oxide in the filter cake is maximized. Extraction.

[0022] According to one embodiment of the present invention, in the impurity salt treatment process, in step f, sodium sulfate in the impurity salt is extracted in the form of sodium sulfate decahydrate by an attached crystallization separation method, so that the solution becomes a mother liquor with sodium chloride as the main component.

[0023] According to one embodiment of the present invention, in step i, an ammonia-soda process is used to make alkali, so that the sodium chloride solution is subjected to ammoniation and carbonation reactions under the intervention of ammonia gas to achieve flue gas decarbonization, and the resultant sodium bicarbonate is used for ion exchange of sodium silicate in step n.

[0024] According to one embodiment of the present invention, in step h, the polyacid iron dissolved simultaneously with the polyacid aluminum in step e is separated by a solubility difference separation method, and the polyacid iron with low solubility is precipitated at the peak point where the aluminum sulfate solubility is the highest.

[0025] According to one embodiment of the present invention, in step i, sodium chloride decomposed from impurities is reacted with concentrated sulfuric acid through double decomposition to produce sodium sulfate and hydrogen chloride, and the hydrogen chloride gas is introduced into the dust removal system of step a to produce hydrochloric acid through hydrolysis.

[0026] According to one embodiment of the present invention, in step g, aluminum hydroxide and ammonium polyacid are generated by neutralization reaction of polyacid aluminum and ammonia, and the aluminum hydroxide is further processed to produce finished aluminum hydroxide or aluminum oxide.

[0027] According to one embodiment of the present invention, by comparing the densities of hydroxides generated by various metal ions, in step k, oxides such as iron hydroxide, nickel hydroxide, copper hydroxide, etc. whose density is greater than that of aluminum hydroxide and are mixed in aluminum hydroxide are separated by sedimentation through a density difference separation method, and other metal oxides whose density is less than that of aluminum hydroxide are separated by flotation.

[0028] According to one embodiment of the present invention, in step 1, calcium carbonate generated by the causticizing reaction in step q and ammonium polyacid generated by the replacement reaction in step g are subjected to double decomposition reaction to produce ammonia, carbon dioxide and calcium polyacid, the ammonia and carbon dioxide are recycled for ammonia-soda decarbonization in step j, and the calcium polyacid enters the next conversion process.

[0029] According to one embodiment of the present invention, in step m, the sodium sulfate generated by the neutralization reaction in step i, the sodium sulfate extracted by the attached crystallization in step f, and the calcium chloride and calcium nitrate produced in step l are subjected to a double replacement reaction to generate calcium sulfate, sodium chloride and sodium nitrate, and the sodium chloride and sodium nitrate are introduced into step j, the sodium chloride absorbs carbon dioxide and ammonia to be converted into sodium bicarbonate, and the sodium nitrate is continuously concentrated as a blending agent and then enters step f for separation by attached crystallization separation method.

[0030] According to one embodiment of the present invention, in step n, the solid silicon dioxide filtered and retained after aluminum dissolution in step e is mixed with a sodium hydroxide solution in a liquid phase melting reactor, and the silicon dioxide therein is converted into sodium silicate through high temperature and high speed stirring.

[0031] According to one embodiment of the present invention, in step o, the sodium bicarbonate solution generated in step i and the sodium silicate solution generated in step n are subjected to ion exchange and hydrothermal synthesis reaction to replace silicon dioxide and sodium carbonate.

[0032] According to one embodiment of the present invention, the silicon dioxide replaced in step o is further treated with acid washing and water washing in step p to remove impurities, thereby optimizing the purity of the silicon dioxide.

[0033] According to one embodiment of the present invention, the sodium carbonate produced in step p is mixed with calcium hydroxide in step q for causticization reaction to generate calcium carbonate and sodium hydroxide, the calcium carbonate enters the reaction system of step l, and the sodium hydroxide is recycled in the silicon dissolution process of step n.

[0034] According to one embodiment of the present invention, the metal ions separated by sedimentation and flotation in step k, the iron hydroxide generated by the replacement reaction of iron sulfate in step g, and the multi-metal oxides obtained by acid washing and water washing in step p are mixed with the entrained silicon dioxide and aluminum hydroxide, and dried in step r to prepare a multi-cation molecular sieve.

[0035] BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Attached Figure 1 : This is a flow chart of the comprehensive utilization of large-cycle process in the coordinated treatment of industrial flue gas pollutants according to an embodiment of the present invention.

[0037] Attached Figure 2 : is a diagram of the steps of comprehensive utilization of large-cycle process in the coordinated treatment of industrial flue gas pollutants according to an embodiment of the present invention.

[0038] Attached Figure 3 : It is a schematic diagram of an upflow flue gas purification device that comprehensively utilizes a large circulation process in the coordinated treatment of industrial flue gas pollutants according to an embodiment of the present invention.

[0039] Attached Figure 4 : It is a plan layout diagram and system device diagram of a pilot project for comprehensive utilization of large-cycle process in the coordinated treatment of industrial flue gas pollutants according to an embodiment of the present invention.

[0040] Attached Figure 5 :This is a flue gas monitoring report for the pilot project of comprehensive utilization of large circulation process in the coordinated treatment of industrial flue gas pollutants according to an embodiment of the present invention

[0041] Attached Figure 6 : This is a test report on the product alumina of the pilot project of comprehensive utilization of large circulation process in the coordinated treatment of industrial flue gas pollutants according to an embodiment of the present invention.

[0042] Attached Figure 7 : It is a schematic diagram of an industrial flue gas purification device that comprehensively utilizes a large circulation process and multiple degassing integration in the coordinated treatment of industrial flue gas pollutants according to an embodiment of the present invention.

[0043] Mode for Carrying Out the Invention

[0044] According to one embodiment of the present invention, the purpose of the present invention is achieved in the following manner.

[0045] 1. Complete flue gas dust removal through bubbling method or mist convection absorption method.

[0046] The dilute sulfuric acid generated by the subsequent desulfurization process, the dilute nitric acid generated by the denitrification process, and the hydrochloric acid produced by the hydrolysis of hydrogen chloride generated by the double decomposition of sulfuric acid and sodium chloride are mixed to form a flue gas dust removal composite solvent with aqua regia effect. The solvent is introduced into the flue gas dust removal system, and the multi-composite acid solvent intercepts the smoke particles through bubbling method or aerosol convection absorption method.

[0047] 2. Remove sulfur oxides and nitrogen oxides from industrial flue gas through adsorption method.

[0048] The flue gas that has been dusted enters the series-wound adsorption purification system (Figure 3) under the blowing of the fan. The structure of the series-wound adsorption purification system is divided into an integral structure or a branch multi-path structure. In these structures, multi-stage purification sections are arranged in layers. Each section consists of a gas gathering layer (Figure 3-1) and an adsorption layer (Figure 3-2). The adsorption layer is densely covered with adsorption purification filters (Figure 3-3). The flue gas flow direction can be designed as an upflow or downflow type, and the desulfurization and denitrification sections are separated by an oxidation layer (Figure 3-4). The function of the oxidation layer is to oxidize the nitrogen monoxide in the flue gas into nitrogen dioxide. The oxidation method can be bubbling (Figure 3-5) or gas-liquid convection. The flue gas first enters the first gas gathering layer and gathers. After being pressure-equalized, it is dispersed to the central cylinder of each purification filter element (Figure 3-6), diffuses outward through the central cylinder, and contacts the sandwiched adsorbent (Figure 3-7) during the diffusion process. Because the adsorbent is an adsorption carrier with alkaline functional group surface adsorption sites after being modified with loaded ions, when the flue gas contacts it, the unique alkaline group of the adsorbent has a strong attraction to the acidic molecules in the flue gas, and the acidic molecules in the flue gas are quickly sucked into the cavity. The flue gas diffuses, gathers, and diffuses outward through the central cylinder of the filter element in the multi-section adsorption system, forming a series-winding purification mode, passing through the series-winding adsorption purification section from bottom to top or from top to bottom, and sulfur dioxide is adsorbed.

[0049] Since the boiling point of nitrogen monoxide in flue gas is low, it is difficult for the adsorbent to adsorb it, so it needs to be oxidized into nitrogen dioxide for adsorption. In the oxidation layer, the nitrogen monoxide is contacted with the oxidant (Figure 3-8) by bubbling or gas-liquid convection, so that it absorbs oxygen atoms and becomes nitrogen dioxide. Oxidants include sulfuric acid, nitric acid, hypochlorous acid, chlorous acid, perchloric acid, sodium chlorate, sodium hypochlorite, sodium chlorite, hydrogen peroxide and other solvents. The newly generated nitrogen dioxide in the flue gas after oxidation enters the adsorption and denitrification layer (Figure 3-9) and is adsorbed by a series-wound adsorption method.

[0050] 3. Desorption of adsorbate and generation of composite acid

[0051] When the adsorbent has adsorbed enough molecules, the adsorption efficiency begins to decline, and the adsorption gradually enters a saturated state, and the desorption process needs to be started. The desorption is to transport liquid water through a high-pressure water pipe and inject it into each purification layer of the adsorption purification system, and spray it to the corresponding purification unit through the injection eye of the desorption ring pipe. The water molecules immerse in the adsorption pores of the activated carbon and dissolve with the adsorbate to transform into ionic desorption liquid. The desorption liquid pushes itself out of the adsorption pores under the action of its own fluidity and then dissolves in the water molecule clusters, that is: SO2 * +O * +H2O=H2SO4,2NO2 * +H2O+1 / 2O2→H2NO3, thereby achieving desorption and generating a binary composite acid composed of a mixture of sulfuric acid and nitric acid.

[0052] In the reaction of dissolving alumina by the acid method, sulfuric acid, nitric acid and hydrochloric acid are mixed to form a multi-component acid with super strong dissolving ability for metal ions. The required sulfuric acid and nitric acid can be obtained in the flue gas desulfurization and denitrification process, while hydrochloric acid needs to be produced by other methods. Considering the conditions for treating hazardous waste salts in the process, the double decomposition process of concentrated sulfuric acid and sodium chloride can not only obtain hydrogen chloride to produce hydrochloric acid, but also obtain sodium sulfate required for subsequent processes, and expand the channels for treating salts. Therefore, this method uses the double decomposition method of sulfuric acid and sodium chloride to produce hydrogen chloride, and introduces hydrogen chloride into the dust removal system to produce hydrochloric acid through hydrolysis, that is, H2SO4+2NaCl+H2O=Na2SO4+2HCl.

[0053] 4. Aluminum Extraction from Fly Ash by Acid Dissolution

[0054] The fly ash acid dissolution aluminum is carried out in a device with reverse cyclonic flotation stirring function. The slurry can be fully mixed in the floating stirring state to increase the frequency of ion collisions. Because the solvent is a ternary compound acid made by mixing nitric acid, sulfuric acid and hydrochloric acid, the mixture of the ternary compound acid enhances the acidity of the solvent. Under this condition, nitrate ions and sulfate ions are mixed to form an oxidant with stronger oxidizing performance, which can quickly dissolve metal aluminum ions. At the same time, the chloride ions (Cl -3 ) can quickly react with aluminum ions (AL +3 ) reacts to generate aluminum chloride, which weakens the potential of aluminum ions under the coordination of chloride ions, and the reaction equilibrium moves. Correspondingly, due to the weakening of the potential of aluminum ions, sulfate ions and nitrate ions can also quickly react with aluminum ions in the solution to generate aluminum sulfate and aluminum nitrate, namely: 6HCl+AL2O3=2ALCl3+3H2O, 3H2SO4+AL2O3=AL2(SO4)3+3H2O, 6HNO3+AL2O3=2AL(NO3)3+6H2O. In this reaction process, the aqua regia effect produced by the polybasic complex acid makes aluminum dissolution easy.

[0055] The polybasic composite acid is prepared by mixing hydrochloric acid: 45% (positive and negative difference does not exceed 5%), sulfuric acid: 40% (positive and negative difference does not exceed 5%), and nitric acid: 15% (positive and negative difference does not exceed 5%) to form a polybasic composite dilute acid solution with a concentration of 5-10%. The polybasic composite dilute acid solution is mixed with fly ash to form a slurry with a solid-liquid ratio of 1:5-15, and then the agitator in the reactor is started and heated to 80-100°C.

[0056] In order to speed up the aluminum dissolution rate and improve the acid dissolution efficiency, the present embodiment adopts an elutriation acid dissolution method, and the mixed liquid is stirred by a counter-rotation or two-way staggered stirring method to make the solid and liquid combine tightly. The concentration of the aluminum dissolving mother liquor is increased to 10-20% as a section through reaction, and the polyacid aluminum solution is separated from the ash by filtering. The ash repeats the above-mentioned elutriation acid dissolution reaction to make the dilute acid aluminum dissolution proceed quickly.

[0057] Because fly ash contains iron oxide, in order to improve the purity of polyacid aluminum, this embodiment uses a solubility difference separation method to select the interval with the largest solubility difference between polyacid aluminum and polyacid iron to separate the polyacid iron. The method uses aluminum sulfate and ferric sulfate as representative elements, and separates the two components by cooling the mixed solution to 25°C (based on the solubility of aluminum sulfate and ferric sulfate solutions at 25°C: Al2(SO4)3: 38.5g / 100ml, Fe2(SO4)3: 20g / 100ml). When the solution temperature is maintained at 25°C, the solubility difference between 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 increasing temperature; when the temperature is less than 25°C, the solubility of the two components also gradually decreases with decreasing temperature. Therefore, the method of the present invention maintains the temperature of the mixed solution at 10°C-55°C, preferably 20°C-30°C, and the solution concentration is maintained at 20g / 100ml-30g / 100ml to form crystals of polyacid iron, which are separated from the mixed solution after sedimentation.

[0058] The separated polyacid aluminum and the heated and dissolved polyacid iron solution are respectively prepared into polymerized polyacid aluminum and polymerized polyacid iron through calcium addition polymerization reaction, or the polyacid aluminum and polyacid iron are respectively prepared into aluminum hydroxide, ferric hydroxide and polyacid ammonium through ammonia addition double decomposition, namely: AL2(SO4)3+6NH3H2O=2AL(OH)3+3(NH4)2SO4, Fe2(SO4)3+6NH3H2O=2Fe(OH)3+3(NH4)2SO4; AL(NO3)3+3NH3H2O=AL(OH)3+3NH4NO3, Fe(NO3)3+3NH3H2O=Fe(OH)3+3NH4NO3; ALCl3+3NH3H2O=AL(OH)3+3NH4Cl, FeCl3+3NH3H2O=Fe(OH)3+3NH4Cl.

[0059] Aluminum hydroxide and other trace elements replaced in it are separated by sedimentation or flotation. The hydroxides such as iron hydroxide, nickel hydroxide, copper hydroxide, etc. with a density greater than aluminum hydroxide quickly settle to the bottom of the mixed slurry due to their greater density and gravity than aluminum hydroxide. The hydroxides such as magnesium hydroxide and titanium hydroxide with a density less than aluminum hydroxide float to the top of the mixed slurry due to their lower gravity than aluminum hydroxide. They are sucked out and separated by layered suction. Aluminum hydroxide is rinsed with clean water to dissolve the polyacid ammonium entrained in it. The pure aluminum hydroxide slurry is filtered and dehydrated by a filter press, and dried at a temperature less than 140°C to produce aluminum hydroxide products, or dried at a temperature greater than 140°C to produce γ-type alumina.

[0060] The polybasic ammonium complex acid solution can be concentrated and crystallized to form solid polybasic ammonium acid, or it can be hydrolyzed with calcium carbonate to form polybasic calcium acid, gaseous ammonia and carbon dioxide. Because the various salts in the polybasic ammonium acid solution belong to strong acid and weak base salts, the ammonium ion hydrolysis produces hydrogen ions, and the hydrogen ions produced by hydrolysis can react with calcium carbonate. The reaction formula is: 2NH4 + +CaCO3=Ca2 ++2H2O, thus completing the hydrolysis of salts, i.e. (NH4)2SO4+CaCO3=CaSO4+NH3+CO2+H2O, NH4NO3+CaCO3=CaNO3+NH3+CO2+H2O, NH4Cl+CaCO3=CaCl2+NH3+CO2+H2O; the decomposed ammonia and carbon dioxide are recycled for alkali production by the ammonia-soda process, and the polybasic acid calcium and the sodium sulfate solution produced by the forward process produce calcium sulfate, sodium chloride and sodium nitrate through a double replacement reaction, i.e. CaCl2+Na2SO4=CaSO4+2NaCl, CaNO3+Na2SO4=CaSO4+NaNO3. While absorbing the impurity sodium sulfate of the miscellaneous salt, the polybasic acid calcium is converted into a single compound calcium sulfate, and the sodium chloride is recycled. Due to the high solubility of sodium nitrate, it is used as a modulator to adjust the solubility of each solution in the ammonia-soda process to make alkali, so that sodium bicarbonate is precipitated at a lower concentration. When the concentration of sodium nitrate increases to a certain value, it is separated by the attached crystallization separation method.

[0061] 5. Grading, washing and extraction of silicon dioxide

[0062] The filter residue filtered out of each stage of the cyclic acid dissolution process is graded and washed to rinse out silicon dioxide of different particle sizes, and the metal impurities on the interface of the silicon dioxide are removed by acid dissolution. Then, the silicon dioxide of different particle sizes is filtered out by washing with clean water by an elutriation and sorting method. The silicon dioxide of different particle sizes is mixed with sodium hydroxide in a ratio of 1:1.2-1.4, preferably 1.33 (based on 100% ingredients) in a silicon dissolution reactor at different reaction times, and water is added to dilute it into a slurry with a concentration of 20-30%. The mixed slurry is stirred at a temperature of 50°C-100°C at a high speed to dissolve the silicon dioxide with sodium hydroxide to prepare sodium silicate. The chemical reaction formula is SiO2+2NaOH=Na2SiO3+H2O.

[0063] The concentration of the sodium silicate solution is controlled at 20-30%, and the sodium bicarbonate produced in the forward process is subjected to a double hydrolysis reaction at a ratio of 1:1.2-1.4 (based on 100% composition) to produce orthosilicic acid, namely Na2SiO3+2N a HCO3+H2O=2Na2CO3+H4SiO4. Orthosilicic acid is hydrothermally synthesized into metasilicic acid at a temperature greater than 102°C, i.e. H4SiO4=H2SiO3+H2O. Metasilicic acid is dried to form silicon dioxide, i.e. H2SiO3==SiO2+H2O.

[0064] The iron hydroxide separated by solubility difference separation method, the nickel hydroxide, magnesium hydroxide, titanium hydroxide and other metal ions separated by density difference separation method, and the impurities separated by silicate pickling and water washing are mixed with the aluminum hydroxide and silicate entrained therein to form a molecular sieve slurry to complete the loaded ion modification. Because the above molecular particle sizes are all less than 1nm, and the ions are positively charged and belong to cations, they are dried and calcined to form a multi-cation molecular sieve with special adsorption advantages for acidic molecules.

[0065] Sodium carbonate and calcium hydroxide are caustized to form calcium carbonate and sodium hydroxide, i.e., Na2CO3+Ca(OH)2=CaCO3+2NaOH. Calcium carbonate and polybasic ammonium acid are decomposed to produce ammonia, carbon dioxide and polybasic calcium acid. Sodium hydroxide is recycled for liquid phase dissolution of silicon dioxide, and ammonia and carbon dioxide are recycled for alkali production by ammonia-soda process.

[0066] To sum up, a large-circulation process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants. Through a dry-wet mixed integrated flue gas purification device, combined with various processes and technologies, the various pollutant components can be removed in an integrated manner while achieving flue gas desulfurization, decarbonization and denitrification. The physical and chemical properties of the pollutants are used to make the various components coexist, decompose and purify to generate a variety of by-products, ultimately achieving the purpose of treating waste with waste.

[0067] In the process of fly ash acid extraction of aluminum, a composite solvent composed of polybasic acids is used. While absorbing the desorption liquid, the polybasic acids are combined into a composite aluminum-dissolving solvent with aqua regia effect, so that the dissolution of metal ions in fly ash can be easily achieved; counter-rotation stirring is used to increase the speed of solid-liquid mixing and the efficiency of ion diffusion, thereby accelerating the chemical transformation of the two-phase medium; the washing acid dissolution is used to promote the role of concentration difference in the chemical reaction, enhance the kinetic potential of ion activity, and improve the efficiency of the chemical reaction; the use of interval acid addition and cyclic reaction makes the fly ash aluminum extraction process unitized and simplifies the process flow; the washing multi-stage sorting of silicon dioxide is used to improve the acid dissolution efficiency and obtain high-purity silicon dioxide of different grades; the strong alkali liquid phase dissolution method is used to dissolve silicon dioxide, which simplifies the silicon dissolution method; double decomposition is used to replace aluminum hydroxide from polybasic aluminum acid, so that the extraction of elemental aluminum can be completed in one step. The main steps are as follows: first, the first step is to remove the impurities of aluminum hydroxide and silicon dioxide, and then the main steps are as follows: first, the main steps are as follows: first, the main steps are as follows: first, the main steps are as follows: second, the main steps are as follows: third, the main steps are as follows: fourth, the main steps are as follows: fifth, the main steps are as follows: fifth, the main steps are as follows: fifth, the main steps are as follows: sixth, the main steps are as follows:

[0068] The method of the present invention will be described in more detail by the following examples, but these examples are for illustrative purposes only and should not be construed as limiting the scope of the present invention.

[0069] Example 1: A pilot project for comprehensive recovery and utilization of carbon, sulfur, nitrate and fly ash in flue gas of Zhungeer Guohua Power Plant of State Energy Group.

[0070] The pilot test was completed by Longyuan (Beijing) Environmental Protection Technology Co., Ltd. and Junggar Guohua Power Plant. The pilot test time is from early August 2022 to the end of June 2023. The pilot test method is an enlarged intermediate experiment from laboratory results to industrial application.

[0071] Pilot test contents:

[0072] 1. Removal, conversion and recycling of sulfur oxides, nitrogen oxides, carbon dioxide and smoke particles in coal-fired flue gas;

[0073] 2. Extraction of aluminum oxide and purification of silicon dioxide from smoke particles;

[0074] 3. Product processing of various products.

[0075] Purpose of pilot test:

[0076] 1. Determine the method of removing carbon dioxide, sulfur dioxide and nitrogen monoxide and the additives used, and determine the dosage of the additives and auxiliary conditions;

[0077] 2. Obtain the purification rate data of carbon dioxide, sulfur oxides, nitrogen oxides and smoke particles in flue gas;

[0078] 3. Verify the role and effect of continuous acid addition and continuous acid dissolution in the fly ash aluminum extraction process in the reverse-rotation reactor, and observe the changes in ion diffusion characteristics and collision frequency under the state of solid-liquid two-phase contact in the reverse-rotation acid dissolution vessel through reverse-rotation floating;

[0079] 4. Determine the best reaction mode, reaction time, reaction temperature and stirring speed;

[0080] 5. Summarize the intermittent acid addition dosage and interval time under certain reaction time, reaction temperature and stirring speed;

[0081] 6. Understand the control range of pH value at each reaction stage;

[0082] 7. Determine the upper and lower limits of the grade and particle size of silica separated by density difference separation method;

[0083] 8. Determine the best method for aluminum sulfate double decomposition and the product purification and productization process route;

[0084] 9. Treatment and utilization of waste liquid.

[0085] Pilot process:

[0086] 1. Layout of pilot equipment

[0087] 1. Production line device system layout: (Attached with the plan layout diagram and pilot system device diagram, Figure 4)

[0088] In the open space on the east side of the 2# boiler of the State Energy Group Zhungeer Guohua Electric Power Co., Ltd., the equipment is arranged in a straight line from south to north. The flue gas is discharged from the main flue at the rear end of the 2# boiler preheater, and is opened and closed by the air valve. It is introduced into the mixed flue gas purifier under the action of the induced draft fan. The flue gas is dusted, decarbonized, desulfurized, and denitrified by the mixed purifier from bottom to top, and then returned to the main flue of the 2# boiler through the return flue through the top air outlet of the purifier. The mixed purifier has a diameter of 2 meters and a height of 9.5 meters. The base occupies an area of ​​2.5m*3.5m=8.75m 2, to the north, 3 meters away from the open space is the reactor layout area, which is equipped with 10 reactors, 2 density difference separators, 1 polymerization reactor (double decomposition reactor), and 1 ammonia still. The reactor base is 1.6 meters high, 3.5 meters wide, 8 meters long, and covers an area of ​​28m 2 , a reactor is installed at every 1 meter interval at both ends of the base, 7 reactors in each row, and the reactor is 2.1 meters high, of which the straight tube is 1.5 meters high and the lower cone is 0.6 meters high. The lower cone is embedded in the base bracket and fixed with bolts. In the middle of the reactors on both sides is an overhead working platform, 1.5 meters wide and 8 meters long. The platform floor is paved with patterned steel plates, and insulating rubber plates are laid on the steel plates. The north end is the entrance for staff. The flue gas purifier, reactor, and high-pressure pump are in the workshop made of insulation board, and two high-pressure atomization drying towers are arranged outside the workshop. An acid storage device is set up on the north side of the pilot workshop, and the device is closed by a wire mesh frame. The process is equipped with an acid addition system, a steam heating system, and a reclaimed water supply system. The main pipeline of the acid addition system is borne from the bottom of the acid preparation tank, and the main valve and branch valve are used to control the supply of acid to each unit of the two rows of reactors; the steam of the steam heating system is introduced from the steam pipeline of the 2# boiler, and the main valve and branch valve are used to control the heat supply to each unit of the two rows of reactors; the reclaimed water supply system is introduced into the pilot area from the connecting pipeline of the boiler reclaimed water system.

[0089] 2. Power configuration: The total power consumption of the pilot system is 143kw / h, including 15kw / h flue induced draft fan, 15kw / h power of 10 reverse rotatory acid dissolvers, 1.5kw / h power of each, 15kw / h in total, 1.1kw / h power of 2 density separators, 1.1kw / h power of polymerization reactor, 3.3kw / h in total, 4kw / h power of circulation pump, 15kw / h power of high pressure pump, 90kw / h power of drying tower electric hot air furnace, totaling 165kw / h power. The power supply of hot air furnace is taken from coal transportation power distribution room, and other power supplies are taken from electric dust removal power distribution room.

[0090] Operation process

[0091] 1. Flue gas purification:

[0092] In the mixed flue gas purifier, carbon dioxide, sulfur dioxide and particulate matter in the flue gas are removed by the two-stage recoil sleeve bubbling purification method, and the nitrogen monoxide in the flue gas is oxidized into nitrogen dioxide.

[0093] First, part of the sulfur dioxide and carbon dioxide are absorbed by water through the first bubbling layer to generate dilute sulfuric acid and carbonic acid, and at the same time, the smoke particles are intercepted and mixed with dilute sulfuric acid and carbonic acid. The smoke particles in the gas phase and the sulfate and carbonate ions in the liquid phase form a turbulent state of forced contact in the recoil sleeve bubbler. Sulfuric acid, carbonic acid and aluminum oxide are forced to contact under the turbulent state and realize fusion transformation at the same time. The outer electrons of aluminum ions output lone pairs of electrons to sulfate and carbonate ions. After sulfate and carbonate obtain electrons, they form coordinated covalent bonds with aluminum ions. The generation of coordinated covalent bonds turns the compound into a polyacid aluminum. The generation of polyacid aluminum increases the concentration of hydrogen ions, and then enhances the electrode potential of the covalent bond, so that the carbon dioxide that is slightly soluble in water is quickly absorbed. Carbon dioxide changes its property of being slightly soluble in water, and the solubility of carbon dioxide in the mixed solution increases.

[0094] The nitric oxide in the flue gas contacts the sodium chlorite solution in the second bubbling layer and is oxidized into nitrogen dioxide, i.e. 2NO+NaCLO2=NaCL+2NO2. The flue gas purified by bubbling goes up into the three-layer adsorption purification section, where the flue gas reciprocates through the adsorption layer in a series-winding motion. The remaining sulfur dioxide, carbon dioxide and nitrogen dioxide generated by oxidation in the flue gas are adsorbed by the special adsorbent of the adsorption layer, i.e. SO2→SO2*, CO2→CO2*, NO2→NO2* (NO2* indicates the adsorption state), and the purified flue gas is introduced into the original flue through the exhaust duct.

[0095] When the adsorption purification section is saturated with adsorption, the adsorbents in the three-layer adsorption purification section are alternately desorbed by water-soluble immersion desorption method. Water dissolves the adsorbed sulfur dioxide, nitrogen dioxide and carbon dioxide in the adsorption pore cavity into dilute sulfuric acid, dilute nitric acid and carbonic acid, that is, SO2*+H2O+1 / 2O2=H2SO4, NO2*+H2O=H2NO3, CO2*+H2O=H2CO3. The mixture of acids of various elements increases the concentration of hydrogen ions, increases its electric potential, and enhances the activity of chemical bonds, turning them into polyacids with greater reaction activity and stronger kinetic potential. The polyacids form coordinated covalent bonds with aluminum ions, greatly enhancing the efficiency of acid dissolution and aluminum extraction.

[0096] 2. Acid dissolution reaction:

[0097] Start the agitator in the reactor, inject the dust removal slurry and the polyacid mixture in a stable state, open the corresponding acid injection pipe and heat it while the reactor is reversely rotating and stirring, and start the lower circulation system at the same time to fully mix the clear liquid with the turbid liquid and the polyacid.

[0098] According to observation, when the mixed solution in the reactor is at 50-80°C and the acidity is maintained at 5%, the clear solution gradually becomes concentrated within 1 hour, the concentration increases rapidly, and the Baume value rises rapidly to 5-6%. When the concentration rises to 5-6Be (Baume), the reaction slows down with the continuous addition of acid. After several hours, the concentration increases slowly, the acidity becomes stronger, and the reaction speed becomes slower. In order to speed up the aluminum extraction speed and improve the acid dissolution efficiency, the pilot project will change the continuous acid addition and progressive reaction into intermittent acid addition and cyclic reaction during operation, and change the continuous acid dissolution aluminum extraction method into a washing acid dissolution method, that is, the concentration of the mixed solution is increased to 5-6 degrees Baume as a section, the mixed solution is filtered through a filter for solid-liquid separation, and the clear liquid of polyacid aluminum (a mixture of aluminum sulfate, aluminum nitrate, and aluminum carbonate) is prepared into polymerized polyacid aluminum through calcium addition polymerization reaction, or prepared into aluminum hydroxide and polyacid ammonium through ammonia addition double decomposition; aluminum hydroxide is separated by sedimentation, and then rinsed with clean water to dissolve the polyacid ammonium entrained therein, and pure aluminum hydroxide is made into slurry and atomized and dried to make γ-type alumina, the polyacid ammonium is heated in an ammonia evaporator to drive out ammonia, the ammonia is circulated in the polyacid aluminum double decomposition, and the remaining polyacid solution is circulated in the fly ash acid dissolution process. Each acid dissolution section serves as an aluminum extraction cycle. The remaining residue in each cycle is repeatedly acid-dissolved. After several repeated washing acid dissolutions, the aluminum in the fly ash is extracted to the maximum extent.

[0099] Pilot test results:

[0100] The project design scale is a flue gas treatment capacity of 20000m 3 / h, actual processing capacity 13000m 3 / h, through mixed flue gas purification, the following effects are achieved: desulfurization rate is greater than 99.8%, outlet SO2 concentration is less than 3mg / m 3 ; Denitrification rate is greater than 88.6%, outlet NOx concentration is less than 3mg / m 3 ; Decarbonization rate is greater than 99.1%, outlet CO2 concentration is less than 0.1%; dust removal rate is greater than 99%, outlet smoke concentration ≤ 5mg / m 3 (The pilot project flue gas monitoring report is attached, Figure 5).

[0101] The fly ash trapped by dust removal is subjected to elutriation acid dissolution by a reverse-rotation acid dissolution device, and 35-50 g / L of polyaluminum (fly ash: water = 1:10 mixed solution) is extracted in each cycle reaction, that is, 35-50 g of polyaluminum is extracted from 0.1 kg of fly ash, which is equivalent to extracting 12-16 g of aluminum trioxide from 0.1 kg of fly ash. The extraction rate each time is 12-16%. The fly ash contains 50% aluminum trioxide, and aluminum can be completely extracted after 3-4 cycles of reaction. According to laboratory analysis, the aluminum hydroxide without washing has an aluminum oxide content of 86.59% (ignition loss 11%) after drying. After the crude aluminum hydroxide is washed, filtered, recombined, iron removed, double decomposed, and dried, the aluminum oxide content is greater than 98% after laboratory analysis (Figure 6).

[0102] Key technical points determined by the pilot project:

[0103] 1. Through pilot operation, it was determined that the hybrid purification method can remove more than 99% of carbon dioxide and sulfur dioxide without adding any ingredients; nitric oxide is oxidized into nitrogen dioxide by oxidation, and then the nitrogen dioxide is removed by adsorption; it was determined that the additive used for oxidizing nitric oxide is sodium chlorite, and the dosage of the additive is proportioned by the relative molecular mass ratio of the chemical formula 2NO+NaCLO2=2NO2+NaCl.

[0104] 2. Through pilot operation, the purification rate data of carbon dioxide, sulfur oxides, nitrogen oxides and smoke particles in flue gas were obtained. Through mixed flue gas purification, the desulfurization rate was greater than 99.8%, the denitrification rate was greater than 88.6%, the decarbonization rate was greater than 99.1%, and the dust removal rate was greater than 99%.

[0105] 3. Through pilot operation, the defects of continuous acid addition, continuous acid dissolution and progressive reaction in the fly ash aluminum extraction process in the reverse rotation reactor were summarized, and the continuous acid addition and progressive reaction process was changed to intermittent acid addition and cyclic reaction process, and the continuous acid dissolution aluminum extraction method was changed to the washing acid dissolution method. It was determined that the solid-liquid two-phase state was in reverse rotation floating contact in the reverse rotation acid dissolver. Under this state, the changes in ion diffusion characteristics and collision frequency were obtained, and the importance of concentration difference in the ion diffusion process in the mixed solution under heating and external force conditions was obtained. It was observed that when the anions and cations in the solution combined and transformed to generate a certain amount of new molecules, the kinetic potential of the anions and cations slowed down, the chemical conversion rate slowed down, and the newly formed molecules became obstacles to ion binding. Based on the above conditions, the pilot operation determined to adopt the dilute acid fast dissolution washing method to enhance the aluminum dissolution efficiency.

[0106] 4. Through pilot testing, it was determined that the best reaction method for extracting aluminum from fly ash mixed solution is dilute acid fast dissolution washing method, the reaction time is one hour per cycle, the reaction temperature is 80-90℃, and the stirring speed is 60r-130r / min. The faster the speed, the better the reaction effect.

[0107] 5. Through pilot operation, it was found that the amount of acid added during one cycle reaction time should not exceed 5%, and the method is one-time addition.

[0108] 6. Through pilot operation, the control range of pH value at each reaction stage was mastered. The starting pH value of each cycle reaction was less than 2, and the pH value was maintained at greater than or equal to 5 at the end.

[0109] 7. During the pilot operation, after the fly ash is acid-dissolved to extract aluminum, the silicon dioxide is separated into two levels of greater than 500um and less than 500um by density difference separation method. The silicon dioxide content greater than 500um is greater than 99%, the silicon dioxide content less than 500um is less than 80%, and the aluminum oxide content is greater than 20%, which can be further processed into high-aluminum molecular sieve.

[0110] 8. Through pilot tests, it was determined that aluminum can be concentrated and purified through the double decomposition of polyacid aluminum, and aluminum and iron can be separated through recombination. The replacement unit components in the double decomposition replacement reaction were determined, and the recombination reaction method and additives as well as the best way to separate aluminum and iron were determined.

[0111] 9. Through pilot operation, we have explored the recycling method of waste liquid and waste gas generated in the double decomposition, thermal decomposition and heavy chemical combination processes, and combined the decomposition and chemical combination changes in the chemical reaction process into a large circulation chain, so that the three-state pollutants in the entire process can achieve zero emissions.

[0112] Embodiment 2:

[0113] 100,000 tons / year fly ash comprehensive utilization and flue gas integrated treatment project

[0114] XXX Thermal Power Co., Ltd. is a power generation enterprise using local high-aluminum coal as fuel, with a power generation capacity of 2*300,000 kw / h and a fly ash production of 400,000-600,000 tons / year. The fly ash composition is as follows: silicon dioxide content 47-51%, aluminum oxide content 35-45%, iron oxide content 2-7%, calcium oxide content 1.5-2.5%, magnesium oxide 1.5-2.5%, sulfur trioxide 1.3-2.26%; 2 million cubic meters / hour of original flue gas is taken for integrated desulfurization, denitrification, decarbonization and dust removal treatment, of which the carbon dioxide content is 10%, the sulfur dioxide content is 2400mg / m3, and the nitrogen monoxide content is 500mg / m3. According to the component analysis, the flue gas is highly polluted, and the fly ash has a complex composition and is high-aluminum fly ash with high utilization value. In order to achieve near-zero emissions of flue gas from coal-fired enterprises and achieve comprehensive management of flue gas and fly ash, the project adopts the large-cycle process in the coordinated management of industrial flue gas pollutants to extract and process alumina and silicon dioxide in fly ash in a graded and step-by-step manner, and removes carbon dioxide, sulfur dioxide, and nitrogen oxides from the flue gas at the same time, so that the flue gas decarbonization, desulfurization, and denitrification and the fly ash aluminum and silicon extraction produce a synergistic effect in the management process, so that the solid waste treatment in the flue gas and the gaseous pollutant management are integrated. The project scale is 100,000 tons / year of fly ash and 2,000,000m3 / hour of flue gas integrated management.

[0115] 1. Flue gas treatment

[0116] In the multi-integrated flue gas purifier, flue gas dust removal is first completed by the gas mist convection absorption method.

[0117] The multi-unit integrated flue gas purifier is a purification device integrating flue gas dust removal, desulfurization and denitrification, and is composed of a wet absorption system and a dry adsorption system, as shown in Figure 7. The dilute sulfuric acid generated by the subsequent desulfurization process, the dilute nitric acid generated by the denitrification process, and the dilute hydrochloric acid generated by the sulfuric acid and sodium chloride double decomposition process are mixed to form a flue gas dust removal composite solvent with aqua regia effect, and the solvent is introduced into the flue gas dust removal system. First, the flue gas (Figure 7-1) enters the soothing absorption section (Figure 7-2) of the dust removal system, and the flue gas is in convective contact with the dust removal agent (Figure 7-3) atomized and falling from the top during the upward movement, and part of the smoke dust particles are intercepted by the dust removal solvent. The flue gas continues to ascend to the cluster absorption section (Figure 7-4), and the gas-liquid contact changes from soothing contact to close contact. The flue gas is in convective contact with the dust removal agent (Figure 7-5) atomized and falling from the top of each cluster channel during the upward movement, and the dust removal efficiency is enhanced. After several layers of gas-liquid convection contact, the particles in the flue gas are intercepted and collected.

[0118] The flue gas after dust removal enters the series-wound adsorption purification system under the blowing of the fan. The structure of the series-wound adsorption purification system is a branch multi-path structure (Figure 7-6), and the flue gas runs in a descending flow. These structures are layered with multi-stage purification sections, each of which is composed of a gas gathering layer (Figure 7-7) and an adsorption layer (Figure 7-8). The adsorption layer is densely covered with adsorption purification filters (Figure 7-9). The desulfurization and denitrification sections are separated by an oxidation layer (Figure 7-10). The function of the oxidation layer is to oxidize the nitrogen monoxide in the flue gas into nitrogen dioxide, and the oxidation method adopts a bubbling method. The flue gas first enters the first gas gathering layer from top to bottom and gathers (Figure 7-11), and then disperses to the central cylinder of each purification filter element after pressure equalization, and diffuses outward through the central cylinder (Figure 7-12). During the diffusion process, it contacts the sandwiched adsorbent (Figure 7-13). Because the adsorbent is an adsorption carrier with alkaline functional group surface adsorption sites after being modified with loaded ions, when the flue gas contacts it, the unique alkaline group of the adsorbent has a strong attraction to the acidic molecules in the flue gas, and the acidic molecules in the flue gas are quickly sucked into the cavity. The flue gas diffuses, gathers, and diffuses outward through the central cylinder of the filter element in the multi-section adsorption system, forming a series-winding purification mode, passing through the series-winding adsorption purification section from top to bottom, and sulfur dioxide is adsorbed.

[0119] Since the boiling point of nitric oxide in flue gas is low, it is difficult for the adsorbent to adsorb it, so it needs to be oxidized into nitrogen dioxide for adsorption. In the oxidation layer, nitric oxide is contacted with the oxidant by bubbling to absorb oxygen atoms and become nitrogen dioxide. Oxidants include sulfuric acid, nitric acid, hypochlorous acid, chlorous acid, perchloric acid, sodium chlorate, sodium hypochlorite, sodium chlorite, hydrogen peroxide and other solvents. The newly generated nitrogen dioxide in the flue gas after oxidation enters the adsorption and denitrification layer (Figure 7-14), and is adsorbed by a series-wound adsorption method.

[0120] When the adsorbent has adsorbed 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 is to transport liquid water through a high-pressure water pipe and inject it into each purification layer of the adsorption purification system, and spray it to the corresponding purification unit through the injection eye of the desorption ring pipe. The water molecules are immersed in the adsorption pores of the activated carbon and dissolve with the adsorbate to transform into ionic desorption liquid. The desorption liquid pushes itself out of the adsorption pores under the action of its own fluidity and then dissolves in the water molecule clusters, thereby achieving desorption and generating a dibasic acid mixed with sulfuric acid and nitric acid. The flue gas is integrated and introduced into the chimney through the annular air outlet (Figure 7-15) for discharge.

[0121] 2. Use industrial salt as a matrix to make sodium bicarbonate by absorbing carbon dioxide.

[0122] In order to widely develop pollutant control channels and reflect the synergistic effect of pollutant control, this embodiment uses industrial hazardous waste salts as a matrix to absorb carbon dioxide in flue gas and ammonia in industrial wastewater, and utilizes the three wastes as resources through the ammonia-soda method.

[0123] The impurities are dissolved in hot water to form a mixed solution with a concentration of 25-32 (degrees Baume), clarified, introduced into the attached crystallization separator and cooled to 20℃-25℃. The attached crystallizer is a circular container with a radius larger than the height. Because the crystallization process is affected by the pressure strength of the solution, the crystallizer should not be too high. A circle of fiber mesh cloth is hung every 150mm in the crystallizer. The upper and lower ends of the mesh cloth are connected and fixed to the upper and lower ring beams. The operators enter and exit from the middle manhole. The mixed solution is introduced into the crystallizer and filled. The supersaturated mixed solution contacts the mesh cloth. The sodium sulfate with the lowest solubility crystallizes first and becomes sodium sulfate decahydrate crystals and attaches to it to become crystal seeds. The crystal seeds continuously attract molecules of the same medium to crystallize and adhere to it. The mesh cloth in the crystallizer becomes a circle of sodium sulfate decahydrate crystal walls. When the crystal thickness of each circle of the wall reaches about 100mm, the remaining mother liquor is discharged from the drain port. According to the characteristic that sodium sulfate decahydrate crystals will dissolve in their own water under the environment with temperature greater than 35.4℃, high-temperature steam is introduced from the steam inlet and a specified pressure is formed under the action of the steam outlet pressure limiting valve to dissolve the sodium sulfate decahydrate crystals. The dissolved sodium sulfate decahydrate solution is discharged from the discharge port. The sodium nitrate in the mixed solution increases by continuously increasing the concentration. When supersaturation is reached, it is separated by attached crystallization.

[0124] Sodium sulfate decahydrate and sodium nitrate are extracted from the mixed solution by an attached crystallization separation method, and the remaining solution becomes a sodium chloride solution containing a single component. According to the chemical reaction principle of the chemical reaction formula NaCl+CO2+NH3+H2O=NH4Cl+NaHCO3, the ratio of ammonia to carbon dioxide is controlled to be 31.3%:68.7%, and the mixture is introduced into the sodium chloride mother liquor in a bubbling manner under a wind pressure of 2000-3000 Pa with flue gas, or is convectively contacted with the atomized sodium chloride mother liquor under a wind pressure of more than 1500-2000 Pa, and sodium bicarbonate and ammonium chloride are generated through reaction, that is, NaCl+CO2+NH3+H2O=NaHCO3+NH4Cl. The sodium bicarbonate is prepared into an additive for ion exchange with sodium silicate generated in a subsequent process through sedimentation and centrifugal dehydration. The ammonium chloride solution reacts with calcium carbonate to generate calcium chloride, ammonia gas and carbon dioxide. The ammonia gas and carbon dioxide are recycled for alkali production by the ammonia-soda process. The calcium chloride and the sodium sulfate solution are replaced by a double replacement reaction to produce calcium sulfate and sodium chloride.

[0125] 3. Aluminum Extraction from Fly Ash by Acid Dissolution

[0126] Aluminum extraction from fly ash by acid is carried out in a device with reverse cyclonic flotation stirring function. The slurry can be fully mixed under the flotation stirring state to increase the frequency of ion collisions. During this reaction process, the aqua regia effect produced by the polybasic composite acid makes aluminum dissolution easy to achieve.

[0127] In order to speed up the aluminum dissolution speed and improve the acid dissolution efficiency, the present embodiment adopts the elutriation acid dissolution method, the mixed liquid is subjected to counter-rotation stirring to make the solid and liquid combine tightly, and the concentration of the aluminum dissolution mother liquor is increased to 10-20% as a section through reaction, and the polyacid aluminum solution is separated from the ash by filtering, and the ash is repeated The above-mentioned elutriation acid dissolution reaction allows the dilute acid aluminum to dissolve rapidly.

[0128] Because fly ash contains iron oxide, in order to improve the purity of aluminum sulfate, this embodiment adopts the solubility difference separation method to select the interval with the largest solubility difference between polyacid aluminum and polyacid iron to separate the polyacid iron from the mixed solution, and the separated polyacid aluminum and polyacid iron solutions are prepared into aluminum hydroxide, ferric hydroxide and polyacid ammonium through ammonia addition double decomposition.

[0129] Aluminum hydroxide and other trace elements displaced therein are separated by sedimentation. Metal oxides with a density greater than that of aluminum hydroxide quickly settle to the bottom due to their greater gravity, while metal oxides with a density less than that of aluminum hydroxide float to the top due to their less gravity, and are separated by layered suction. Aluminum hydroxide is rinsed with clean water to dissolve the polybasic ammonium acid entrained therein, and the pure aluminum hydroxide slurry is filtered and dehydrated by a filter press, and dried at a temperature less than 140°C to produce finished aluminum hydroxide products, or dried at a temperature greater than 140°C to produce γ-type alumina.

[0130] The polybasic ammonium complex acid solution drives out carbon dioxide and ammonia by double decomposition with calcium carbonate. The carbon dioxide and ammonia are recycled for alkali production by the ammonia-soda process. The calcium chloride and calcium nitrate in the product polybasic calcium acid are replaced with sodium sulfate solution by double replacement reaction to produce calcium sulfate, sodium chloride and sodium nitrate.

[0131] The sulfuric acid and nitric acid continuously produced by flue gas desulfurization and denitrification are combined with the hydrochloric acid produced by the continuous reaction of sulfuric acid and sodium chloride to form a polybasic compound acid. The aqua regia effect produced by the polybasic compound acid in the fly ash acid dissolution process greatly improves the efficiency of acid-dissolved alumina, and after repeated washing acid dissolution, the aluminum in the fly ash is extracted to the maximum extent.

[0132] 4. Grading, washing and extraction of silicon dioxide

[0133] The filter residues from each stage of the cyclic acid dissolution process are graded and washed to remove silicon dioxide of different particle sizes.

[0134] In the above reaction process, on the one hand, the aluminum oxide in the slurry is absorbed and converted by the polybasic composite acid, and on the other hand, the silicon dioxide in the slurry is cut and purified by the polybasic acid while the acid dissolution conversion is carried out. Because the silicon dioxide in the fly ash is subjected to high temperature during the coal combustion process, the expansion coefficient of the metal impurities carried therein is different from that of the silicon dioxide, which is rapidly oxidized under the action of high temperature and combined with the silicon dioxide grains to loosen, and at the same time, the high temperature breaks up the silicon dioxide grains with cracks, and the broken grains are in a fine powder form into microsilicon powder, which is not only easy to remove impurities, but also easy to rinse and purify. This embodiment adopts the acid dissolution method to remove the metal impurities on the interface of silicon dioxide by acid dissolution, and then adopts the washing and sorting method to filter out silicon dioxide of different particle sizes by rinsing with clean water, and reacts the silicon dioxide with sodium hydroxide in a two-way staggered stirring reactor, and the silicon dioxide with a particle size greater than 500um reacts for 6-8 hours, and the silicon dioxide with a particle size less than 500um reacts for 4-6 hours, and the sodium hydroxide is dissolved by high-speed stirring to prepare sodium silicate.

[0135] The sodium silicate solution and the sodium bicarbonate produced in the forward process are double-decomposed in proportion to produce orthosilicic acid, the orthosilicic acid is hydrothermally synthesized to produce metasilicic acid, and the silicic acid is dried to produce silicon dioxide.

[0136] The impurities such as iron hydroxide separated by solubility difference separation method, nickel hydroxide, magnesium hydroxide, titanium hydroxide separated by density difference separation method are mixed with aluminum hydroxide and silicic acid entrained therein, and dried and calcined to make a polyvalent cationic molecular sieve. Because cations are positive ions under ionization conditions and are alkaline, they have affinity for acidic molecules and are suitable for desulfurization, denitrification, decarbonization, and dechlorination of gaseous pollutants. It is an adsorption product with broad application prospects.

[0137] Sodium carbonate generated by double decomposition of sodium silicate and sodium hydroxide is reacted with calcium hydroxide to generate calcium carbonate and sodium hydroxide through causticization reaction, and the carbonate is introduced into double decomposition reaction with polybasic ammonium acid, and the sodium hydroxide is recycled for liquid phase dissolution of silicon dioxide.

[0138] V. Benefit Analysis

[0139] The acid method extracts 80% of aluminum oxide, i.e. 32,000 tons, and the alkaline method converts 80% of silicon dioxide, i.e. 39,000 tons; the consumption of polyacids is 92,000 tons, calculated based on 45% hydrochloric acid, 40% sulfuric acid, and 15% nitric acid, which means 41,400 tons of hydrochloric acid, 36,800 tons of sulfuric acid, and 13,800 tons of nitric acid are consumed. Flue gas treatment capacity 2000000m 3 / h, the flue gas contains 2400mg / m 3 , nitric oxide content 500mg / m 3, 38,400 tons of sulfur dioxide and 17,600 tons of nitrogen oxides are removed annually. Except for the purchase of 43,000 tons of concentrated sulfuric acid for the production of hydrogen chloride, the acid cycle in the process can achieve balance; in the subsequent treatment process, 70,500 tons of sodium chloride and 25,300 tons of sodium sulfate are consumed, and 100,000 tons of miscellaneous salts (containing NaCl: 70%, containing Na2SO4: 25%) need to be processed. Sodium carbonate and calcium hydroxide are causticized to obtain sodium hydroxide for recycling, 95,000 tons of calcium hydroxide and 63,700 tons of ammonia (calculated at 100% content) are consumed; 130,000 tons of nano calcium sulfate and 70,500 tons of ammonium chloride are generated. The fixed asset investment of the 100,000 tons / year fly ash treatment and 2 million cubic meters of flue gas treatment project is 100 million yuan, the annual operating cost is 300 million yuan, the output product value is greater than 1 billion yuan, and the profit created by renewable resources is greater than 500 million yuan.

[0140] This invention is a technological revolution in the field of environmental governance, especially for the management of large-scale solid waste in thermal power companies, turning harm into benefit and turning waste into treasure, fundamentally solving the chronic problems that plague the sustainable development of thermal power companies. The application of a large-cycle process that comprehensively utilizes industrial flue gas pollutants in the coordinated management is in line with national conditions and the times. In terms of innovation, this process uses desulfurization, denitrification, and decarbonization derivatives as the main raw materials for treating solid waste fly ash, and while treating gas, solid, and liquid pollutants, it also utilizes various pollutants as resources. The demand for sulfuric acid in the acid-based dissolution of alumina can liberate the use of high-sulfur coal, while achieving zero emissions in pollutant control and turning pollutants into treasure, minimizing pollution control costs and maximizing pollution control benefits; on the technical level, the process uses desulfurization and denitrification liquid to extract aluminum, which increases the intensity of aluminum dissolution; the use of mixed salts for decarbonization provides an ion exchange medium for the conversion of sodium silicate while realizing the recycling of carbon dioxide, and the derivative hydrochloric acid is mixed with sulfuric acid and nitric acid. Acids are combined to form an aluminum-dissolving solvent with aqua regia effect; iron is removed by combination, decomposition and heavy chemical methods to purify alumina; carbonation, ammonia-alkali and ion exchange methods are flexibly applied to aluminum extraction from fly ash and flue gas decarbonization, and a synergistic effect is produced in the application, thereby realizing a large cycle of the process; in terms of economic benefits, pollutants are recycled in the process, which reduces the cost of pollution control and generates greater added value; in terms of social benefits, gas, solid and liquid pollutants are synergistically removed, and truly benign governance is achieved from the air to the ground, which reduces environmental pressure and reduces environmental risks for the country and the people. It is a great cause that benefits the country and the people and benefits mankind.

Claims

1. A large-cycle process for comprehensive utilization in the coordinated treatment of industrial flue gas pollutants, the process comprising: a. Sulfuric acid generated by desulfurization in the subsequent step b, nitric acid generated by denitration in the step c, and hydrochloric acid generated by the double replacement reaction of sodium chloride in the step i are mixed to prepare a flue gas dust removal solvent, and dust is removed by a multi-component composite acid solvent to produce an aqua regia effect in the fly ash dissolved aluminum; b. The sulfur dioxide in the flue gas after dust removal is removed by adsorption; c. Remove nitrogen oxides from flue gas after desulfurization by oxidation + adsorption method; d. Desorb sulfur dioxide and nitrogen dioxide in the adsorbent by water-soluble desorption method and generate sulfuric acid and nitric acid; e. Dissolve aluminum oxide in fly ash and convert it into polyacid aluminum in a multi-stage aluminum dissolving reactor; f. Dissolve the impurity salts and separate the impurity component sodium sulfate by attached crystallization separation method, so that the solution becomes a mother liquor with sodium chloride as the main component; j. Through the ammonia-alkali process, sodium chloride solution is used in the presence of ammonia gas to decarbonize flue gas through ammoniation and carbonation reactions, and the resulting sodium bicarbonate is used for ion exchange of sodium silicate; h. Separate aluminoferrate by solubility difference separation method; i. Introduce hydrogen chloride generated by double replacement reaction of sodium chloride and sulfuric acid into step a, generate hydrochloric acid by hydrolysis and add it into the composite acid solution of step e along with dust removal slurry; g. In the replacement system, polyacid aluminum and polyacid iron are decomposed by adding ammonia to replace aluminum hydroxide, iron hydroxide and polyacid ammonium; k. Separate impurity metal ions mixed in aluminum hydroxide by density difference separation method; l. Reaction of polyacid ammonium with calcium carbonate generated by causticization reaction in step n to produce ammonia and carbon dioxide by double decomposition reaction, and recycle ammonia and carbon dioxide for alkali production in step j by ammonia-soda method; m. Double replacement of sodium sulfate produced in step f and step i with calcium chloride and calcium nitrate produced in step l The reaction generates calcium sulfate, sodium chloride and sodium nitrate; n. Silicon dioxide and sodium hydroxide are mixed in a liquid phase melting reactor, and sodium silicate is generated by high temperature and high speed stirring reaction; o. Sodium bicarbonate generated in the forward process is added to the sodium silicate solution, and silicic acid and sodium carbonate are replaced by ion exchange and hydrothermal synthesis reaction; p. Silicic acid is acid-washed and water-washed to maximize the removal of impurities and optimize the purity of silicon dioxide; q. Sodium carbonate is reacted with calcium hydroxide in a causticizing reactor to produce calcium carbonate and sodium hydroxide; r. The impurity metal ions separated in step k, the iron hydroxide generated in step j, the multi-metal oxides obtained by acid-washing and water-washing in step p, and the entrained silicon dioxide and aluminum hydroxide are mixed to form a multi-cation molecular sieve.

2. According to claim 1, a large-cycle process for comprehensive utilization of industrial flue gas pollutants in collaborative treatment, in step a, sulfuric acid generated by desulfurization in the subsequent step b, nitric acid generated by denitrification in step c, and hydrochloric acid produced by hydrolysis of hydrogen chloride produced by double replacement reaction of sodium chloride and sulfuric acid in step i are mixed to form a multi-component composite dilute acid solvent with a concentration of 5-10%, and the composite solvent is introduced into a flue gas dust removal system, and dust is removed by bubbling method or aerosol convection contact method.

3. According to claim 1, a large circulation process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants, and the flue gas after dust removal in step a is sent to a multi-integrated desulfurization purification device under the action of a fan, and the desulfurization system in step b contacts the adsorbent in the adsorption filter element in a series flow state, and the sulfur dioxide in the flue gas is adsorbed by the adsorbent, and the flue gas is desulfurized.

4. According to claim 1 and claim 3, a large circulation process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants. The series-winding flow state is that the flue gas first enters the gas gathering layer of the series-winding adsorption system, passes through the central cylinder of the adsorption purification filter element densely distributed in the layer, diffuses outward through the central cylinder, and contacts with the stacked adsorbent in the interlayer during the diffusion process. The flue gas diffuses, gathers, and diffuses outward through the central cylinder of the filter element in the multi-section adsorption system, forming a series-winding purification mode.

5. According to the comprehensive utilization of large circulation process in the coordinated treatment of industrial flue gas pollutants as described in claim 1 and claim 3, the adsorbent of the sandwich stacked adsorbent of the purification filter element includes granular carbon-based, wood-based activated carbon or granular ball molecular sieve.

6. According to claim 1, a large circulation process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants. The flue gas that has completed desulfurization in step b enters the denitrification system in step c under the blowing of a relay fan, and enters a bubbler or an aerosol convection converter under a certain wind pressure, so that the flue gas is in gas-liquid contact with a solvent added with an oxidant, and the oxidant oxidizes the nitric oxide in the flue gas into nitrogen dioxide, and then the nitrogen dioxide is adsorbed by adsorption.

7. According to the large-cycle process for comprehensive utilization in the coordinated treatment of industrial flue gas pollutants described in claim 1 and claim 6, the oxidant for oxidizing nitric oxide in the flue gas includes chlorous acid, hypochlorous acid, perchloric acid, sodium chlorite, sodium hypochlorite, sodium perchlorate and hydrogen peroxide solution, preferably sodium chlorite solution.

8. According to the comprehensive utilization of large-circulation process in the coordinated treatment of industrial flue gas pollutants as described in claim 1 and claim 6, the nitrogen dioxide is adsorbed by adsorption because the boiling point of nitrogen dioxide is 21°C, which is suitable for adsorption removal, and the method is the same series-wound adsorption as the removal of sulfur dioxide.

9. According to claim 1, a large-cycle process for comprehensive utilization in the coordinated treatment of industrial flue gas pollutants, when the sulfur dioxide adsorbed by the desulfurization system or the nitrogen dioxide adsorbed by the denitrification system reaches adsorption saturation, the two adsorbents are desorbed by a water-soluble impregnation method, sulfur dioxide is desorbed to generate sulfuric acid, and nitrogen dioxide is desorbed to generate nitric acid; wherein: Liquid water is transported through high-pressure water pipes and injected into each purification layer of the adsorption purification system, and then sprayed to the corresponding purification unit through the injection eye of the desorption ring pipe. Water molecules penetrate into the adsorption pores of the activated carbon and dissolve with the adsorbate to transform into ionic desorption liquid. The desorption liquid pushes itself out of the adsorption pores under the action of its own fluidity and then dissolves in the water molecule clusters, thereby achieving desorption.

10. According to claim 1, a large circulation process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants, sulfuric acid, nitric acid, sulfuric acid generated by desulfurization and denitrification are mixed with hydrochloric acid generated by the sodium chloride double decomposition process to form a composite acid, and the polyaluminum oxide in the fly ash is dissolved in a multi-stage aluminum dissolving converter by the polyaluminum composite acid composed of sulfuric acid, nitric acid and hydrochloric acid to generate polyaluminum acid.

11. According to the large-cycle process for comprehensive utilization in the coordinated treatment of industrial flue gas pollutants described in claim 1 and claim 10, the hydrochloric acid generated by double decomposition is first generated by double decomposition reaction of sulfuric acid and sodium chloride to generate hydrogen chloride, and then enters the dust removal system to generate hydrochloric acid through hydrolysis, that is, H2SO4+2NaCl=Na2SO4+2HCl.

12. According to claim 1 and claim 10, the comprehensive utilization of large circulation process in the coordinated treatment of industrial flue gas pollutants, the ratio of the polyvalent composite acid composed of sulfuric acid, nitric acid and hydrochloric acid is sulfuric acid: 40%, with a positive and negative difference of no more than 5%; Hydrochloric acid: 45%, with a positive or negative difference of no more than 5%; Nitric acid: 15%, with a positive or negative difference of no more than 5%, so that it produces an aqua regia effect in molten aluminum.

13. The large-cycle process for comprehensive utilization in the coordinated treatment of industrial flue gas pollutants according to claim 1 and claim 12, wherein the aqua regia effect is characterized in that: The mixture of sulfuric acid, nitric acid and hydrochloric acid increases the acidity of the solvent. Under this condition, nitrate ions and sulfate ions are mixed to form A more powerful oxidant that can quickly dissolve aluminum ions, while the chloride ions (Cl -3 ) can quickly react with aluminum ions (AL +3 ) reacts to generate aluminum chloride, which weakens the potential of aluminum ions under the coordination of chloride ions, and the reaction equilibrium shifts. Correspondingly, due to the weakening of the potential of aluminum ions, sulfate ions and nitrate ions can also quickly react with aluminum ions in the solution to generate aluminum sulfate, aluminum nitrate, and aluminum chloride. In this reaction process, the aqua regia effect produced by the polybasic composite acid improves the efficiency of aluminum dissolution.

14. According to claim 1 and claim 10, a large-circulation process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants. The multi-stage aluminum dissolution process is to filter part of the polyacid aluminum dissolved and converted in the first stage through a filter pressing facility to separate the liquid phase of the polyacid aluminum from the filter cake, and the polyacid aluminum enters the replacement reaction system; the solid phase filter cake is mixed again with the subsequently continuously produced composite polyacid solvent, and the first stage aluminum dissolution process is repeated in the next stage aluminum dissolution reactor, and the filter cake is repeatedly dissolved, filtered, and solid-liquid separated until the aluminum oxide in the filter cake is maximized. Extraction.

15. According to claim 1, a large-circulation process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants. In the process of treating the miscellaneous salts, sodium sulfate in the miscellaneous salts is extracted in the form of sodium sulfate decahydrate by an attached crystallization separation method. In the ammoniation and carbonation process, sodium chloride is used to decarbonize the flue gas under the intervention of ammonia and carbon dioxide gases to generate sodium bicarbonate, and the sodium bicarbonate is used for ion exchange with sodium silicate.

16. According to claim 1 and claim 15, a large-circulation process for comprehensive utilization in the coordinated treatment of industrial flue gas pollutants is described, wherein the sodium sulfate in the impurity salt is extracted as sodium sulfate decahydrate by the attached crystallization separation method, which means that the impurity salt is dissolved to form a mixed solution with a concentration of 25-32 (degrees Baume), clarified, introduced into an attached crystallization separator and cooled to 20°C-25°C, the supersaturated mixed solution is contacted with a mesh cloth, and the sodium sulfate with a smaller solubility is first crystallized into sodium sulfate decahydrate crystals and attached thereto to become crystal seeds, the crystal seeds continuously attract molecules of the same medium to adhere to their crystals, and the mesh cloth in the crystallizer becomes a wall of sodium sulfate decahydrate crystals in several layers. According to the characteristic that sodium sulfate decahydrate crystals will dissolve in their own water under an environment with a temperature greater than 35.4°C, high-temperature water vapor is introduced from the steam inlet and a specified pressure is formed under the action of a steam outlet pressure limiting valve to dissolve the sodium sulfate decahydrate crystals, and the dissolved sodium sulfate decahydrate solution is discharged from the discharge port, thereby separating the sodium sulfate in the mixed solution.

17. According to claim 1 and claim 16, a large-circulation process for comprehensive utilization in the coordinated treatment of industrial flue gas pollutants is described, wherein the crystallizer is a circular container and / or a rectangular crystallizer with a diameter greater than its height, and a layer of fiber mesh cloth is hung every 100-200 mm in the crystallizer, and the upper and lower ends of the mesh cloth are connected and fixed to the upper beam and the lower beam, and when the crystallization thickness of each layer of the wall reaches 80-120 mm, the remaining mother liquor is discharged from the drain port.

18. According to claim 1 and claim 15, a large-cycle process for comprehensive utilization in the coordinated treatment of industrial flue gas pollutants is described, wherein the ammonia and carbon dioxide gases are contacted with a sodium chloride solution in a bubbling manner at a pressure of 2000Pa-3000Pa to convert them, or are contacted with a sodium chloride solution in an aerosol convection manner at a pressure of 1500Pa-2000Pa to convert them, and the reaction equation is: NaCl+NH4+CO2+H2O=NH4Cl+NaHCO3, and The ratio of ammonia to carbon dioxide is 31.3%:68.7%.

19. According to claim 1, a large-cycle process for comprehensive utilization of industrial flue gas pollutants in collaborative treatment, the polyacid iron dissolved simultaneously with polyacid aluminum in the aluminum dissolution process is separated by solubility difference separation method, the iron oxide is mainly ferric sulfate, and the ferric sulfate with low solubility is precipitated at the peak point with the highest solubility of polyacid aluminum, which is characterized by: When the solution temperature is maintained at 25°C, the solubility of ferric sulfate is 20g / 100L, and the solubility of polyacid aluminum is 38.5g / 100mL. The solubility difference between the two components is greater than 18.5g / 100ml. Therefore, the temperature of the mixed solution is maintained at 20°C-30°C, and the solution concentration is maintained at 20g / 100ml-30g / 100ml to allow ferric sulfate to crystallize and then be separated from the mixed solution.

20. According to claim 1, a large circulation process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants. In the replacement system, the polyacid aluminum generated by the aluminum dissolution process and the ferric sulfate separated by the solubility difference separation system are respectively decomposed by adding ammonia to replace the aluminum hydroxide, ferric hydroxide and ammonium sulfate, ammonium nitrate and ammonium chloride. The reaction formula is: AL2(SO4)3+6NH3H2O=2AL(OH)3+3(NH4)2SO4, Fe2(SO4)3+6NH3H2O=2Fe(OH)3+3(NH4)2SO4; AL(NO3)3+3NH3H2O=AL(OH)3+3NH4NO3, ALCl+3NH3H2O=AL(OH)3+3NH4Cl.

21. According to claim 1, a large circulation process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants, and the displaced aluminum hydroxide and ferric hydroxide are respectively washed with clean water to remove impurities and then dehydrated, and dried at a temperature less than 140°C to form aluminum hydroxide and ferric hydroxide products, or dried at a temperature greater than 140°C to form aluminum oxide and iron oxide products.

22. According to claim 1, a large-cycle process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants, wherein the ammonium chloride solution produced by the ammonia-soda process is concentrated and supersaturated crystallized to form solid ammonium chloride, and the polyacid ammonium solution produced by adding polyacid aluminum to ammonium is double-decomposed with calcium carbonate to produce polyacid calcium, ammonia and carbon dioxide, and the three products are treated separately for recycling.

23. According to claim 1 and claim 22, a large-scale recycling process for comprehensive utilization of industrial flue gas pollutants in collaborative treatment, the recycling of the product is recycling ammonia and carbon dioxide in ammonia-soda process for alkali production, and The sodium sulfate generated by the neutralization reaction of polybasic calcium with sulfuric acid and sodium chloride, the sodium sulfate extracted by crystallization, and the calcium chloride and calcium nitrate produced by the double decomposition process are subjected to double replacement reaction to generate calcium sulfate, sodium chloride and sodium nitrate, that is, CaCl2+Na2SO4=CaSO4+2NaCl, Ca(NO3)2+NaSO4=CaSO4+2NaNO3, and Sodium chloride and sodium nitrate are introduced into the ammonia-soda process. Sodium chloride absorbs carbon dioxide and ammonia and is converted into sodium bicarbonate. Sodium nitrate is used as a blending agent and is continuously concentrated before being separated through the dependent crystallization separation method.

24. According to the large-cycle process for comprehensive utilization in the coordinated treatment of industrial flue gas pollutants described in claim 1 and claim 23, the polyacid calcium and sodium sulfate solution generate calcium sulfate through a double replacement reaction, and the reaction is achieved by two compounds through ion exchange. The calcium sulfate generated in this process is a nano calcium sulfate.

25. According to the large-cycle process for comprehensive utilization of industrial flue gas pollutant coordinated treatment in claim 1, by comparing the densities of hydroxides generated by various metal ions, the iron hydroxide (density 3.4-3.9 g / cm2) mixed in aluminum hydroxide with a density greater than that of aluminum hydroxide is separated by a density difference separation method in a density difference separator. 3 ), nickel hydroxide (density 4.9g / cm 3 ), copper hydroxide (density 3.36g / cm 3 ) and other oxides leak through the discharge port at the bottom of the separator and mix with aluminum hydroxide (density 2.4 / cm 3 ) separation; magnesium hydroxide (density 2.36 / cm 3 ) and other metal oxides with density lower than aluminum hydroxide are separated by suction at the top of the separator.

26. According to claim 1, a large-circulation process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants, wherein the solid silicon dioxide filtered out after aluminum dissolution is mixed with a sodium hydroxide solution in a liquid phase melting reactor, and the silicon dioxide therein is converted into sodium silicate through high-temperature and high-speed stirring, and the reaction equation is 2NaOH+SiO2=Na2SiO3+H2O.

27. The large-cycle process for comprehensive utilization in the coordinated treatment of industrial flue gas pollutants according to claim 1 and claim 26, wherein the liquid phase melting is carried out by dissolving and converting silicon dioxide through liquid sodium hydroxide, silicon dioxide and sodium hydroxide are mixed in a ratio of 1:1.2-1.4, preferably 1.33 (based on 100% components), and water is added to dilute the mixture into a slurry with a concentration of 20-30%, and The mixed slurry is heated to 50°C-100°C and reacted in a floating stirring reactor, and Silica with a particle size greater than 500um reacts for 6-8 hours, and silica with a particle size less than 500um reacts for 4-6 hours, and The stirrer speed is maintained at 40-1400r / min to allow sodium hydroxide to dissolve silicon dioxide to form sodium silicate.

28. According to claim 1, a large-cycle process for the comprehensive utilization of industrial flue gas pollutants in the coordinated treatment, sodium bicarbonate is added to the sodium silicate solution in an ion exchanger, and silicon dioxide and sodium carbonate are replaced by ion exchange and hydrothermal synthesis reaction, the ion exchange equation is: 2NaHCO3+NaSiO3=2NaCO3+H4SiO4; the hydrothermal synthesis equation is: H4SiO4→H2SiO3+H2O.

29. According to claim 1 and claim 28, a large-cycle process for comprehensive utilization in the coordinated treatment of industrial flue gas pollutants, the ion exchange method is to mix solid sodium bicarbonate and liquid sodium silicate solution in a certain proportion, and heat and stir to merge the solid and liquid phases, characterized in that: The concentration of the sodium silicate solution is controlled at 10-15%, and the sodium silicate solution is double-decomposed with sodium bicarbonate at a ratio of 1:1.2-1.4 (based on 100% composition) to produce orthosilicic acid, and Orthosilicic acid is prepared by hydrothermal synthesis at a temperature greater than 102°C.

30. According to claim 1, a large-circulation process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants, and the silica generated by hydrothermal synthesis is further optimized in purity by acid washing and water washing. The acid washing is to neutralize the alkaline components attached to the surface of the silica by strong acid or weak acid; the water washing is to remove impurities by rinsing with clean water.

31. According to the large-cycle process for the comprehensive utilization of the coordinated treatment of industrial flue gas pollutants as described in claim 1, sodium carbonate generated by ion exchange of sodium silicate is reacted with calcium hydroxide in a causticizing reactor to generate calcium carbonate and sodium hydroxide, and the reaction equation is: Na2CO3+Ca(OH)2=CaCO3+2NaOH.

32. According to claim 1 and claim 31, a large-cycle process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants, wherein the calcium carbonate generated by the causticizing reaction is applied to the double decomposition process to react with polybasic ammonium acid, namely, (NH4)2SO4+CaCO3=CaSO4+2NH3+CO2+H2O, 2NH4Cl+CaCO3=CaCl2+NH3+CO2+H2O, NH4NO3+CaCO3=CaNO3+NH3+CO2+H2O and Recycling sodium hydroxide into the liquid phase melting silicon process; and Recycling ammonia and carbon dioxide in the ammonia-soda process; and The polybasic calcium acid was applied to a double displacement reaction with a sodium sulfate solution.

33. According to claim 1, a large circulation process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants, and the metal ions separated by sedimentation and flotation methods and the multi-metal oxides separated by acid washing and water washing are mixed with the entrained silicon dioxide and aluminum hydroxide to form a multi-cation molecular sieve, and the method is: nanoparticles mixed with multiple elements are calcined and self-differentiated to form nanomolecular sieves, or high-pressure atomization drying is used to form molecular sieve hollow particle balls.

34. According to the comprehensive utilization of large-circulation process in the coordinated treatment of industrial flue gas pollutants as described in claim 1 and claim 33, the multi-metal oxides obtained after acid washing and water washing include metal oxides carried in silicon dioxide and metal oxides carried in sodium bicarbonate, wherein the metal oxides carried in sodium bicarbonate come from metal elements in miscellaneous salts.

35. According to claim 1 and claim 33, a large circulation process is comprehensively utilized in the coordinated treatment of industrial flue gas pollutants. The spheres of molecular sieve hollow particle balls made by high-pressure atomization drying are stacked, poured with silica sol or other agents to bond them into blanks of desired shapes, and sintered at a temperature of 600°C-900°C in a calcining kiln to form cationic foam adsorption bricks.

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