CN111437712A - Flue gas desulfurization method and system based on ammonia-magnesium combined strengthening phosphate rock slurry method - Google Patents
Flue gas desulfurization method and system based on ammonia-magnesium combined strengthening phosphate rock slurry method Download PDFInfo
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- 239000003546 flue gas Substances 0.000 title claims abstract description 103
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 85
- 238000000034 method Methods 0.000 title claims abstract description 65
- 238000006477 desulfuration reaction Methods 0.000 title claims abstract description 62
- 230000023556 desulfurization Effects 0.000 title claims abstract description 62
- 239000002367 phosphate rock Substances 0.000 title claims abstract description 46
- 238000007613 slurry method Methods 0.000 title claims abstract description 14
- WQVVYEYAFFYPIX-UHFFFAOYSA-N azane;magnesium Chemical compound N.[Mg] WQVVYEYAFFYPIX-UHFFFAOYSA-N 0.000 title claims abstract description 12
- 238000005728 strengthening Methods 0.000 title claims abstract description 9
- 239000002002 slurry Substances 0.000 claims abstract description 91
- 239000011268 mixed slurry Substances 0.000 claims abstract description 58
- OJMIONKXNSYLSR-UHFFFAOYSA-N phosphorous acid Chemical compound OP(O)O OJMIONKXNSYLSR-UHFFFAOYSA-N 0.000 claims abstract description 39
- 238000006243 chemical reaction Methods 0.000 claims abstract description 25
- MXZRMHIULZDAKC-UHFFFAOYSA-L ammonium magnesium phosphate Chemical compound [NH4+].[Mg+2].[O-]P([O-])([O-])=O MXZRMHIULZDAKC-UHFFFAOYSA-L 0.000 claims abstract description 24
- 229910052567 struvite Inorganic materials 0.000 claims abstract description 24
- 238000005406 washing Methods 0.000 claims abstract description 22
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims abstract description 17
- 239000000395 magnesium oxide Substances 0.000 claims abstract description 17
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims abstract description 17
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 17
- 239000001301 oxygen Substances 0.000 claims abstract description 17
- 235000011114 ammonium hydroxide Nutrition 0.000 claims abstract description 16
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 16
- 238000007599 discharging Methods 0.000 claims abstract description 13
- 229910019142 PO4 Inorganic materials 0.000 claims abstract description 12
- 239000013078 crystal Substances 0.000 claims abstract description 12
- 239000010452 phosphate Substances 0.000 claims abstract description 8
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims abstract description 8
- 150000007524 organic acids Chemical class 0.000 claims abstract description 7
- 230000003009 desulfurizing effect Effects 0.000 claims description 38
- 239000007788 liquid Substances 0.000 claims description 32
- 238000005507 spraying Methods 0.000 claims description 31
- 230000008569 process Effects 0.000 claims description 19
- 238000002156 mixing Methods 0.000 claims description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 15
- 238000000227 grinding Methods 0.000 claims description 14
- 238000005192 partition Methods 0.000 claims description 12
- 238000003756 stirring Methods 0.000 claims description 10
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 9
- 239000002245 particle Substances 0.000 claims description 8
- 239000007921 spray Substances 0.000 claims description 8
- 239000007787 solid Substances 0.000 claims description 7
- VZCYOOQTPOCHFL-OWOJBTEDSA-N Fumaric acid Chemical compound OC(=O)\C=C\C(O)=O VZCYOOQTPOCHFL-OWOJBTEDSA-N 0.000 claims description 6
- YGSDEFSMJLZEOE-UHFFFAOYSA-N salicylic acid Chemical compound OC(=O)C1=CC=CC=C1O YGSDEFSMJLZEOE-UHFFFAOYSA-N 0.000 claims description 6
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 claims description 3
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 claims description 3
- 239000001530 fumaric acid Substances 0.000 claims description 3
- FJKROLUGYXJWQN-UHFFFAOYSA-N papa-hydroxy-benzoic acid Natural products OC(=O)C1=CC=C(O)C=C1 FJKROLUGYXJWQN-UHFFFAOYSA-N 0.000 claims description 3
- 229960004889 salicylic acid Drugs 0.000 claims description 3
- 239000011975 tartaric acid Substances 0.000 claims description 3
- 235000002906 tartaric acid Nutrition 0.000 claims description 3
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 claims description 3
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 claims description 2
- 230000000149 penetrating effect Effects 0.000 claims description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N sulfur dioxide Inorganic materials O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 abstract description 48
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 abstract description 39
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 abstract description 24
- 229910021529 ammonia Inorganic materials 0.000 abstract description 17
- 239000011777 magnesium Substances 0.000 abstract description 15
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 abstract description 12
- 229910052749 magnesium Inorganic materials 0.000 abstract description 12
- 230000008901 benefit Effects 0.000 abstract description 10
- 238000010521 absorption reaction Methods 0.000 abstract description 8
- 230000000694 effects Effects 0.000 abstract description 8
- 239000000463 material Substances 0.000 abstract description 5
- 238000002360 preparation method Methods 0.000 abstract description 4
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 abstract description 2
- 239000011575 calcium Substances 0.000 abstract description 2
- 229910052791 calcium Inorganic materials 0.000 abstract description 2
- 238000010668 complexation reaction Methods 0.000 abstract description 2
- 238000002386 leaching Methods 0.000 abstract description 2
- 238000005457 optimization Methods 0.000 abstract 1
- 238000007254 oxidation reaction Methods 0.000 description 10
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 8
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 8
- 239000007789 gas Substances 0.000 description 8
- 229910052698 phosphorus Inorganic materials 0.000 description 8
- 239000011574 phosphorus Substances 0.000 description 8
- 230000003647 oxidation Effects 0.000 description 7
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 6
- 239000000779 smoke Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 5
- 239000000428 dust Substances 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- 229910052717 sulfur Inorganic materials 0.000 description 5
- 239000011593 sulfur Substances 0.000 description 5
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 4
- 230000002745 absorbent Effects 0.000 description 4
- 239000002250 absorbent Substances 0.000 description 4
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 4
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 4
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 4
- 239000003245 coal Substances 0.000 description 4
- 230000018109 developmental process Effects 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 235000011130 ammonium sulphate Nutrition 0.000 description 3
- 239000006227 byproduct Substances 0.000 description 3
- 239000003344 environmental pollutant Substances 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 3
- 239000000347 magnesium hydroxide Substances 0.000 description 3
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 3
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 3
- JESHZQPNPCJVNG-UHFFFAOYSA-L magnesium;sulfite Chemical compound [Mg+2].[O-]S([O-])=O JESHZQPNPCJVNG-UHFFFAOYSA-L 0.000 description 3
- 231100000719 pollutant Toxicity 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 229910052723 transition metal Inorganic materials 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- PQUCIEFHOVEZAU-UHFFFAOYSA-N Diammonium sulfite Chemical compound [NH4+].[NH4+].[O-]S([O-])=O PQUCIEFHOVEZAU-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 238000006555 catalytic reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- XLYOFNOQVPJJNP-ZSJDYOACSA-N heavy water Substances [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 description 2
- -1 i.e. Substances 0.000 description 2
- 229910000360 iron(III) sulfate Inorganic materials 0.000 description 2
- LPHFLPKXBKBHRW-UHFFFAOYSA-L magnesium;hydrogen sulfite Chemical compound [Mg+2].OS([O-])=O.OS([O-])=O LPHFLPKXBKBHRW-UHFFFAOYSA-L 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 150000003624 transition metals Chemical class 0.000 description 2
- 241000282414 Homo sapiens Species 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 239000000443 aerosol Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- ZETCGWYACBNPIH-UHFFFAOYSA-N azane;sulfurous acid Chemical compound N.OS(O)=O ZETCGWYACBNPIH-UHFFFAOYSA-N 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000005183 environmental health Effects 0.000 description 1
- 239000003337 fertilizer Substances 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 159000000003 magnesium salts Chemical class 0.000 description 1
- 235000019341 magnesium sulphate Nutrition 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 235000015097 nutrients Nutrition 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- NIFIFKQPDTWWGU-UHFFFAOYSA-N pyrite Chemical compound [Fe+2].[S-][S-] NIFIFKQPDTWWGU-UHFFFAOYSA-N 0.000 description 1
- 229910052683 pyrite Inorganic materials 0.000 description 1
- 239000011028 pyrite Substances 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000004513 sizing Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 229910001428 transition metal ion Inorganic materials 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Images
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-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/80—Semi-solid phase processes, i.e. by using slurries
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/48—Sulfur compounds
- B01D53/50—Sulfur oxides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
- B01D2258/02—Other waste gases
- B01D2258/0283—Flue gases
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Treating Waste Gases (AREA)
Abstract
The invention discloses a flue gas desulfurization method and a system based on an ammonia-magnesium combined strengthening phosphate slurry method, wherein the method comprises the following steps: s1, adding ammonia water and magnesium oxide into the phosphorite slurry to prepare mixed slurry; s2, containing SO2The flue gas is contacted and reacted with the sprayed mixed slurry to remove SO in the flue gas2(ii) a And S3, discharging the flue gas after washing the slurry, introducing oxygen into the reacted mixed slurry for reaction, then returning the mixed slurry to the step S2 for continuously washing the flue gas, and when the solubility of the magnesium ammonium phosphate in the mixed slurry reaches the preset requirement, sending the mixed slurry to a crystallizer to produce magnesium ammonium phosphate crystals. According to the invention, the high desulfurization capacity of the ammonia, magnesium and phosphorite pulp is utilized, and the advantages of the absorption capacity of the ammonia, magnesium and phosphorite pulp on sulfur dioxide and process optimization are combined, so that the sulfuric acid leaching reaction of phosphorite is promoted, and the desulfurization effect of the phosphorite pulp is enhanced; before the material preparation, the invention also comprises the step of adding organic acid when the material is ground to be finer, and the organic acid can be enhanced through mechanochemical activationThe coordination and complexation with calcium are strong, crystal lattices are damaged, and the removal of sulfur dioxide is accelerated.
Description
Technical Field
The invention belongs to the technical field of flue gas desulfurization, and particularly relates to a flue gas desulfurization method and a flue gas desulfurization system based on an ammonia-magnesium combined strengthening phosphate slurry method.
Background
With the rapid development of economy in China, the pace of industrialization and urbanization is constantly accelerated, and the demand of energy is more and more serious. Coal is used as a main energy source in China, and the consumption of the coal accounts for about 80 percent of the total energy. While coal is combusted to provide energy, a large amount of smoke dust and SO are generated2And the atmospheric pollutants seriously restrict the sustainable development of the world economy and the health of human beings.
SO2As one of the main pollutants of the atmosphere, the environmental health of the atmosphere is seriously influenced. Controlling SO2There are many ways to discharge the amount. The method mainly comprises the following steps: before, during and after combustion (flue gas desulfurization). The flue gas desulfurization is the most widely commercialized desulfurization mode in the world at present, and has the advantages of mature technology and reliable operation. The methods for desulfurizing flue gas mainly comprise a wet method, a semi-dry method and a dry method, wherein the wet desulfurization process is the most widely used desulfurization method at present and mainly comprises a limestone-gypsum method, a sodium-alkali method, an ammonia method, a magnesium method, a double-alkali method, an organic amine method, a phosphorite slurry method and the like.
The ammonia desulfurization is based on alkaline desulfurizing agent (ammonia or ammonia water) and acidic SO2Chemical reaction takes place to form (NH)4)2SO4The process of (1). After the 90 s of the 20 th century, the application of ammonia flue gas desulfurization technology is on a gradually rising trend along with the continuous development of the synthetic ammonia industry, the technological progress and other reasons. The ammonia flue gas desulfurization technology has many advantages which are not possessed by the flue gas desulfurization technology, including difficult scaling of a desulfurization system, wide adaptability to the sulfur content in coal, no secondary pollution, simple system, small equipment volume, low energy consumption and the like. However, at the same time, ammonia desulfurization has several problems:
(1) because ammonia is volatile, ammonia is produced and loses raw materials along with the overflow of the desulfurization tail gas.
(2) Difficulty of ammonium sulfite oxidation: NH (NH)4+Significantly hinder O2Dissolution in aqueous solution. When the salt concentration is high<0. At 5 mol/L, the oxidation rate of the ammonium sulfite increases with increasing concentration, and when this limit is exceeded, the oxidation rate decreases with increasing concentration.
(3) The solubility of ammonium sulfate changes little with temperature, and the method for crystallizing and separating out ammonium sulfate generally adopts evaporative crystallization, and consumes extra steam.
(4) Under certain conditions, solid ammonia bisulfite is also formed in the gas phase, i.e., vapor phase precipitation. The initially formed solid appears as an ultrafine powder, on the micron scale, called an aerosol.
The magnesium method for desulfurizing fume is to mix magnesium oxide powder with process water in a certain proportion to prepare magnesium hydroxide slurry, and the slurry is mixed with SO2To produce magnesium sulfite or magnesium bisulfite, and part of the magnesium sulfite is oxidized by air to magnesium sulfate. The magnesium desulfurization technology is a mature flue gas desulfurization technology, and has the characteristics and technical advantages that: sufficient raw material source, high desulfurization efficiency, reliable operation, low investment, no secondary pollution, good solubility of magnesium salt, difficult blockage and stable chemical property of byproducts. However, the magnesium desulfurization technology also has the following defects:
(1) most of magnesium ore resources are concentrated in a few provinces, and the popularization and application of the method are restricted by the raw material source and the transportation cost;
(2) the regeneration method has high calcination temperature and high energy consumption, the effective utilization of byproducts restricts the development of the method, the requirement on the dust removal of flue gas is high, better comprehensive economic benefit is difficult to obtain, and the cost is difficult to compete with large-scale sulfuric acid enterprises.
The phosphorite slurry method for flue gas desulfurization uses phosphorite slurry as an absorbent and transition metal iron ions in phosphorite as a catalyst, utilizes the residual oxygen in the flue gas to catalytically oxidize the sulfurous acid in the solution into sulfuric acid, continuously increases the sulfur capacity of the solution and absorbs SO in the flue gas2Ability of (2) with sulfur formedThe acid and the phosphorite further generate chemical reaction to achieve the aim of desulfurization. The essence of the phosphorite slurry desulfurization is that SO is removed2The sulfuric acid is converted into sulfuric acid for decomposing phosphorite, no waste is discharged in the whole desulfurization process, no waste water is generated, a new product can be obtained, and the method is a green recycling economic route. The method has the advantages of high desulfurization efficiency, low operation cost and simple flow, and is suitable for coupling with phosphorus chemical industry production enterprises. However, this method has a disadvantage in that it requires a slurry containing transition metal ions as an absorbent and does not generate SO in all cases2Enterprises of flue gas are widely used. Therefore, it is necessary to develop a flue gas desulfurization method and a system based on an ammonia-magnesium combined enhanced phosphate slurry method, which have excellent desulfurization effect and high resource utilization rate.
Disclosure of Invention
The first purpose of the invention is to provide a flue gas desulfurization method based on an ammonia-magnesium combined strengthening phosphate rock slurry method.
The second purpose of the invention is to provide a system for realizing the flue gas desulfurization method based on the ammonia-magnesium combined strengthening phosphate slurry method.
The first object of the present invention is achieved by comprising the steps of:
s1, adding ammonia water and magnesium oxide into the phosphorite slurry to prepare mixed slurry, and controlling the pH value to be more than 7;
s2, containing SO2The flue gas is contacted and reacted with the sprayed mixed slurry to remove SO in the flue gas2；
S3, washing the flue gas by the slurry, demisting and discharging; and introducing oxygen into the reacted mixed slurry for reaction, then uniformly stirring, returning to the step S2 for continuously washing the flue gas, and when the solubility of the magnesium ammonium phosphate in the mixed slurry reaches a preset requirement, sending to a crystallizer to produce magnesium ammonium phosphate crystals.
The second purpose of the invention is realized by comprising a blending tank, a first delivery pump, a second delivery pump, a circulating tank, a desulfurizing tower, a liquid distributor, a demister, a water tank, a third delivery pump, a first stirrer, a second stirrer and a discharge pump, wherein the blending tank is communicated with the circulating tank through a pipeline and a first delivery pump, the bottom of the desulfurizing tower is communicated with the circulating tank through a pipeline, the blending tank is provided with the first stirrer, the liquid distributor is provided with three liquid distributors, the upper part in the desulfurizing tower is sequentially arranged from bottom to top, the circulating tank is communicated with the liquid distributor through a pipeline and a second delivery pump, the pipeline is provided with a pH detector, the circulating tank is provided with the second stirrer, a smoke outlet at the top of the desulfurizing tower is provided with the demister, a water spray pipe is arranged above the liquid distributor, the water tank passes through the pipeline and passes through the third delivery pump, the device is communicated with a spray pipe, a discharge pump is arranged at a discharge port at the lower part of the desulfurizing tower, and a smoke inlet and an oxygen inlet are arranged at the lower part of the side surface of the desulfurizing tower.
The invention has the beneficial effects that: the method not only makes full use of the characteristic that alkaline substances and transition metal Fe ions contained in the phosphorite pulp have a multi-valence oxidation state and are easy to form a complex with external electrons and molecules, so that the valence state of sulfur is changed under the catalysis and oxidation action of the Fe ions, and is converted into dilute sulfuric acid, and the dilute sulfuric acid further decomposes the phosphorite to generate dilute phosphoric acid and sulfate so as to achieve the aim of desulfurization; in addition, ammonia water and magnesium oxide are added into the phosphorite slurry, and two substances with high desulfurization activity are obtained, so that phosphoric acid generated by phosphorite slurry desulfurization reacts with ammonia and magnesium to generate insoluble magnesium ammonium phosphate, the sulfuric acid leaching reaction of phosphorite is promoted, the desulfurization effect of the phosphorite slurry is enhanced, and the desulfurization efficiency is improved; the method has the advantages of high reaction rate and simple operation, and can ensure that SO in the flue gas is not only contained in the flue gas2The content is far lower than the national emission standard, the advantages of the ammonia process, the magnesium process and the phosphorite slurry process are fully utilized, the problems of the traditional conventional ammonia process and magnesium process desulfurization technology are solved, the resource utilization rate is high, the investment is low, the economic value of byproducts is improved, no secondary pollutant is generated, and the method has obvious social and economic benefits; the method has the advantages of high reaction rate and simple operation. The insoluble precipitate generated by the invention contains various nutrient elements such as nitrogen, phosphorus, magnesium and the like, is a good slow-release fertilizer, and can realize resource recycling; before the material preparation, the method also comprises the step of adding organic acid when the material is ground to be finer, and the coordination and complexation effect with calcium can be enhanced, crystal lattices can be destroyed, and the removal of sulfur dioxide can be accelerated through the mechanochemical activation effect; the system integrates material mixing and circulating sprayingThe functions of washing and recovering magnesium ammonium phosphate are integrated, and the operation is convenient; the liquid distributor has a rotary structure, and under the action of the annular shells of the forward rotation liquid distributor, the reverse rotation liquid distributor and the upper and lower adjacent liquid distributors, the washing effect is greatly enhanced, SO that SO in the flue gas2The reaction with the sprayed slurry is more thorough, thereby improving the desulfurization effect.
Drawings
FIG. 1 is a schematic diagram of the system of the present invention;
FIG. 2 is a schematic diagram of a liquid distributor;
FIG. 3 is a schematic top view of the liquid distributor;
FIG. 4 is a schematic view of the structure of the connecting pipe;
in the figure: 1-a blending tank, 2-a first delivery pump, 3-a second delivery pump, 4-a circulating tank, 5-a desulfurizing tower, 6-a liquid distributor, 6 a-an annular shell, 6 b-a clapboard, 6 c-an outer gear ring, 6 d-a rack, 6 e-a rack chute, 6 f-a driving cylinder, 6 g-a support frame, 6 h-a flexible slurry inlet pipe, 6 i-a first slurry spraying head, 6 j-a second slurry spraying head, 6 k-an annular connecting main pipe, 6 l-a first slurry spraying head connecting branch pipe, 6 m-a second slurry spraying head connecting branch pipe, 7-a demister, 8-a water tank, 9-a third delivery pump, 10-a first stirrer, 11-a second stirrer, 12-a discharge pump, 13-a water spraying pipe and 14-a smoke inlet, 15-oxygen inlet.
Detailed Description
The invention is further described with reference to the accompanying drawings, but the invention is not limited in any way, and any alterations or substitutions based on the teaching of the invention are within the scope of the invention.
The method comprises the following steps:
s1, adding ammonia water and magnesium oxide into the phosphorite slurry to prepare mixed slurry, and controlling the pH value to be more than 7;
s2, containing SO2The flue gas is contacted and reacted with the sprayed mixed slurry to remove SO in the flue gas2；
S3, washing the flue gas by the slurry, demisting and discharging; and introducing oxygen into the reacted mixed slurry for reaction, then uniformly stirring, returning to the step S2 for continuously washing the flue gas, and when the solubility of the magnesium ammonium phosphate in the mixed slurry reaches a preset requirement, sending to a crystallizer to produce magnesium ammonium phosphate crystals.
In the desulfurization process of the method, the partial chemical reactions involved are as follows:
(1) removal of SO from ammonia2The absorption process carried out:
2NH4OH+SO2←→ (NH4)2SO3+H2O (1)
SO2+(NH4)2SO3+H2O←→ 2NH4HSO3(2)
NH4OH+NH4HSO3←→ (NH4)2SO3+H2O (3)
in the course of ammonia desulfurization absorption, NH4HSO3To SO2Has no absorption capacity, and (NH)4)2SO3To SO2Has good absorption capacity, is the main absorbent in the ammonia process, so NH in solution4HSO3When a certain concentration is reached, treatment measures need to be taken, and an air oxidation method is generally adopted to oxidize unstable intermediate sulfite generated by the flue gas desulfurization absorption reaction into stable ammonium sulfate. The main oxidation reaction is simply expressed as:
2NH4HSO3+O2→ 2NH4HSO4(4)
2(NH4)2SO3+O2→ 2(NH4)2SO4(5)
(2) the desulfurization mechanism of magnesium oxide is to utilize alkaline oxide to react with water to generate hydroxide, and then to react with sulfurous acid solution generated by dissolving sulfur dioxide in water to perform acid-base neutralization reaction. The reaction principle comprises the following steps:
Mg(OH)2+SO2+5H2O←→ MgSO3.6H2O↓ (1)
MgSO3+SO2+HO←→ Mg(HSO3)2↓ (2)
Mg(HSO3)2+Mg(OH)2+10H2O←→ 2MgSO3.6H2O↓ (3)
and (3) oxidizing the magnesium sulfite and the magnesium bisulfite by using air. The main oxidation reaction is simply expressed as:
Mg(HSO3)2+1/2O2+6H2O→ MgSO4· 7H2O↓ (4)
2MgSO3+1/2O2+7H2O→ MgSO4· 7H2O↓ +SO2↑ (5)
SO produced by oxidation2And the sulfite is removed by reacting with the absorption liquid in the absorption tower.
(3) The phosphorus ore pulp is used for treating sulfur-containing flue gas, namely, the catalysis and oxidation of alkaline substances and transition metal Fe ions contained in the phosphorus ore pulp are utilized to lead SO to be treated2The dilute sulfuric acid is converted to generate dilute sulfuric acid, and the dilute sulfuric acid is further used for decomposing phosphorite to generate dilute phosphoric acid and sulfate, and the reaction equation is as follows:
2FeSO4+SO2+O2＝Fe2(SO4)3(1)
Fe2(SO4)3+SO2+2H2O＝2FeSO4+2H2SO4(2)
the two formulas are combined:
2SO2+O2+2H2O
2H2SO4(3)
(4) adding ammonia water and magnesium oxide into the phosphorite slurry to ensure that phosphoric acid generated by desulfurizing the phosphorite slurry reacts with ammonia and magnesium to generate insoluble magnesium ammonium phosphate, wherein the main reaction is as follows:
Mg2++NH4++P04 3-+6H2O＝MgNH4PO4· 6H2O↓ (1)
Mg2++NH4++HPO4 -+6H2O----MgNH4PO4· 6H2O↓ +H+(2)
Mg2++NH4++H2PO4 -+6H2O-----MgNH4PO4· 6H2O↓ +2H+(3)。
preferably, before the step of S1, the method further comprises grinding the phosphorus ore slurry for 5-30 min, adding an organic acid, and further grinding until the particle size is less than 1mm, wherein the organic acid is citric acid, fumaric acid, EDTA, salicylic acid or tartaric acid.
Preferably, the particle size of the phosphorite slurry is at least 90 percent of the phosphorite slurry passing through a 500-mesh sieve; the phosphorite pulp is a necessary production process in the production process of phosphorus chemical industry, is derived from phosphorite processing and mineral dressing production processes, and does not need separate processing, so that the preparation process of the desulphurization absorbent is saved.
Preferably, the solid content of the mixed slurry is 30-40 wt%, the mass concentration of ammonia water is 10-20%, and the mass concentration of magnesium oxide is 10-20%.
Preferably, the flue gas is generated by preparing sulfuric acid from pyrite, and the flue gas is dedusted, SO in the flue gas2The content of (A) is 2000-3000 mg/m3。
As shown in fig. 1-4, the system for implementing the flue gas desulfurization method based on the ammonia-magnesium combined strengthening phosphate slurry method comprises a blending tank 1, a first delivery pump 2, a second delivery pump 3, a circulation tank 4, a desulfurization tower 5, a liquid distributor 6, a demister 7, a water tank 8, a third delivery pump 9, a first stirrer 10, a second stirrer 11 and a discharge pump 12, wherein the blending tank 1 is communicated with the circulation tank 4 through a first delivery pump 2 via a pipeline, the bottom of the desulfurization tower 5 is communicated with the circulation tank 4 through a pipeline, the blending tank 1 is provided with the first stirrer 10, the liquid distributors 6 are three and are sequentially arranged at the upper part in the desulfurization tower 5 from bottom to top, the circulation tank 4 is communicated with the liquid distributor 6 through a pipeline, the pipeline is provided with a pH detector, the circulation tank 4 is provided with the second stirrer 11, 5 top exhaust port of desulfurizing tower be equipped with defroster 7, 6 tops of liquid distributor be equipped with spray pipe 13, basin 8 pass through the pipeline, and through third delivery pump 9, communicate with spray pipe 13, 5 lower part bin outlet of desulfurizing tower be equipped with discharge pump 12, 5 side lower parts of desulfurizing tower be equipped with into smoke mouth 14, advance oxygen mouth 15.
Preferably, the desulfurizing tower 5 is a cylindrical desulfurizing tower, the liquid distributor 6 comprises an annular shell 6a, two partition plates 6b, an outer toothed ring 6c, two racks 6d, a rack chute 6e, a driving cylinder 6f, a support frame 6g, a flexible slurry inlet pipe 6h, a first slurry spraying head 6i and a second slurry spraying head 6j, the two partition plates 6b are arranged on the inner side of the annular shell 6a in a cross shape, the inner side of the annular shell 6a is divided into four flue gas channels, the annular shell 6a is internally provided with an annular groove, the outer side surface of the annular shell 6a is opposite to the inner side surface of the desulfurizing tower 5, one section of the annular groove is provided with an opening penetrating through the inner wall of the desulfurizing tower 5, the outer toothed ring 6c is sleeved on the outer side of the annular shell 6a, the outer toothed ring 6c is arranged in the annular groove, the racks 6d are arranged on the outer side of the desulfurizing tower 5, and one section of the racks 6d, the part of the rack 6d located in the opening is meshed with the teeth of the outer gear ring 6c, the side face of the rack 6d is in sliding fit with the rack sliding groove 6e, the supporting frame 6g is arranged at the bottom of the rack sliding groove 6e, a piston rod of the driving air cylinder 6f is connected with the end of the rack 6d, so that the driving air cylinder 6f can drive the rack 6d to move in the rack sliding groove 6e in a reciprocating mode, the first slurry spraying heads 6i are multiple and are respectively arranged at the bottom of the annular shell 6a, the second slurry spraying heads 6j are multiple and are respectively arranged on two sides of the partition plate 6b, one end of the flexible slurry inlet pipe 6h is connected with a slurry inlet pipe joint on the side face of the desulfurizing tower 5, and the other end of the flexible slurry inlet pipe is communicated with the first slurry spraying heads 6i and the second slurry spraying heads 6j through connecting pipes.
Preferably, the bottom of the annular housing 6a is inclined inward, so that the first slurry spraying head 6i sprays slurry obliquely and guides the flue gas to the flue gas channel.
Preferably, the flexible slurry inlet pipe 6h is positioned on the top of the annular shell 6a and the partition plate 6b, and the middle part of the flexible slurry inlet pipe 6h is arranged on the top of the partition plate 6b through a pipeline fixing support.
Preferably, the slurry inlet end of the connecting pipeline is positioned at the top of the annular shell 6a, the slurry inlet end of the connecting pipeline is connected with the end part of the flexible slurry inlet pipe 6h, and the connecting pipeline is respectively positioned in the annular shell 6a and the partition plate 6 b; the connecting pipeline comprises an annular connecting main pipe 6k and a first slurry spraying head connecting branch pipe 6l which are arranged in the annular shell 6a, and a second slurry spraying head connecting branch pipe 6m which is arranged in the partition board 6b, wherein the first slurry spraying head connecting branch pipe 6l is respectively connected with the annular connecting main pipe 6k, the bottom of the first slurry spraying head connecting branch pipe 6l is connected with a first slurry spraying head 6i, the second slurry spraying head connecting branch pipe 6m is connected with the annular connecting main pipe 6k, and the side surface of the second slurry spraying head connecting branch pipe 6m is connected with a second slurry spraying head 6 j.
Preferably, the rotation directions of the annular shells 6a of the upper and lower adjacent liquid distributors 6 in the desulfurizing tower 5 are opposite.
The working principle and the working process of the system of the invention are as follows: firstly, preparing phosphorite pulp, ammonia water and magnesium oxide into mixed slurry through a blending tank 1 and a first delivery pump 2; the mixed slurry is sent into a circulating tank 4 through a first delivery pump 2; the second stirrer 11 continuously stirs the mixed slurry in the circulating tank 4; the mixed slurry in the circulating tank 4 is sent into a liquid distributor 6 through a second delivery pump 3;
the mixed slurry is sprayed out from a first slurry spraying head 6i and a second slurry spraying head 6j through a flexible slurry inlet pipe 6h, an annular connecting header pipe 6k, a first slurry spraying head connecting branch pipe 6l and a second slurry spraying head connecting branch pipe 6 m; in the slurry spraying process, the driving cylinder 6f drives the rack 6d to reciprocate in the rack sliding groove 6e, in the moving process of the rack 6d, the annular shell 6a is driven to rotate for a certain angle in the desulfurizing tower 5 through the outer gear ring 6c, then the driving cylinder 6f drives the annular shell 6a to rotate reversely to the initial position, and the forward rotation and reverse rotation processes are repeated continuously; in the rotating process, the spraying areas of the first guniting head 6i and the second guniting head 6j are increased; the flue gas enters the desulfurizing tower 5 from the flue gas inlet 14 and goes upward, and in the upward process, the flue gas contacts with the sprayed mixed slurry in a countercurrent way and reacts to remove SO in the flue gas2(ii) a When the flue gas passes through the flue gas channel of the liquid distributor 6, on one hand, the flue gas is continuously washed by the slurry sprayed by the second slurry spraying head 6j, and on the other hand, the SO in the flue gas is enabled to be generated under the actions of continuous forward rotation and reverse rotation of the annular shell 6a and reverse rotation directions of the annular shells 6a of the two adjacent liquid distributors 62The reaction with the sprayed slurry is more thorough;
after being washed by the slurry, the flue gas is demisted by a demister 7 and then discharged outside, the reacted mixed slurry falls on the bottom of a desulfurizing tower 5, and meanwhile, oxygen is continuously introduced into the bottom of the desulfurizing tower 5 through an oxygen inlet 15; the mixed slurry enters a circulating tank 4 from the bottom of a desulfurizing tower 5, then enters a liquid distributor 6 along with a second delivery pump 3 again, and is sprayed and washed by smoke in a circulating way; when the solubility of magnesium ammonium phosphate in the feed liquid at the bottom of the desulfurization tower meets the preset requirement, the feed liquid is discharged through a discharge pump 12; the liquid level is supplied to the bottom of the desulfurization tower through the water tank 8, the third delivery pump 9, and the water spray pipe 13.
The present invention will be further described with reference to examples 1 to 6.
Example 1
Adding ammonia water and magnesium oxide into the phosphorite slurry to prepare mixed slurry, and controlling the pH value to be more than 7; containing SO2The flue gas is contacted and reacted with the sprayed mixed slurry to remove SO in the flue gas2(ii) a Washing the flue gas by the slurry, demisting and discharging; and introducing oxygen into the reacted mixed slurry for reaction, then uniformly stirring, returning to the step S2 for continuously washing the flue gas, and when the solubility of the magnesium ammonium phosphate in the mixed slurry reaches a preset requirement, sending to a crystallizer to produce magnesium ammonium phosphate crystals.
Example 2
Grinding the phosphorite slurry for 5min, adding citric acid, and further grinding until the particle size is less than 1 mm; adding ammonia water and magnesium oxide into the phosphorite slurry to prepare mixed slurry, and controlling the pH value to be more than 7; containing SO2The flue gas is contacted and reacted with the sprayed mixed slurry to remove SO in the flue gas2(ii) a Washing the flue gas by the slurry, demisting and discharging; and introducing oxygen into the reacted mixed slurry for reaction, then uniformly stirring, returning to the step S2 for continuously washing the flue gas, and when the solubility of the magnesium ammonium phosphate in the mixed slurry reaches a preset requirement, sending to a crystallizer to produce magnesium ammonium phosphate crystals.
Example 3
Grinding the phosphorus ore pulp for 25min, adding tartaric acid, and continuously grinding until the particle size is less than 1 mm; adding ammonia water and magnesium oxide into the phosphorite slurry to prepare mixed slurry, and controlling the pH value to be more than 7; containing SO2The flue gas is contacted and reacted with the sprayed mixed slurry to remove SO in the flue gas2(ii) a Flue gas warp sizing agentAfter washing, discharging the solution after demisting; and introducing oxygen into the reacted mixed slurry for reaction, then uniformly stirring, returning to the step S2 for continuously washing the flue gas, and when the solubility of the magnesium ammonium phosphate in the mixed slurry reaches a preset requirement, sending to a crystallizer to produce magnesium ammonium phosphate crystals.
Example 4
Grinding the phosphorus ore pulp for 30min, adding fumaric acid, and continuously grinding until the particle size is less than 1 mm; to treat the inlet SO2The concentration is 2000mg/m3Taking the flue gas as an example, the inlet flue gas temperature is 120 ℃, and the flue gas and the mixed slurry sprayed circularly are subjected to countercurrent contact reaction from bottom to top to remove SO in the flue gas2Controlling the gas velocity of the desulfurizing tower to be 35m/s and the liquid-gas ratio to be 7L/m3(ii) a Blending the phosphorite slurry in the mixed slurry in a blending tank until the granularity is at least 90 percent and the granularity is over 500 meshes, controlling the solid content to be 30 weight percent, controlling the mass concentration of the added ammonia water to be 10 percent, controlling the mass concentration of the added magnesium oxide to be 10 percent, and controlling the pH value to be more than 7; containing SO2The flue gas is contacted and reacted with the sprayed mixed slurry to remove SO in the flue gas2(ii) a Washing the flue gas with slurry, demisting, discharging, and discharging SO2≤30mg/m3The dust concentration is less than or equal to 5mg/m3(ii) a Introducing oxygen into the reacted mixed slurry for reaction, then uniformly stirring, returning to the step S2 for continuously washing the flue gas, and when the solubility of magnesium ammonium phosphate in the mixed slurry reaches a preset requirement, sending the mixed slurry to a crystallizer to produce magnesium ammonium phosphate crystals; the desulfurization efficiency of the flue gas treated by the method can reach more than 95 percent.
Example 5
Grinding the phosphorite slurry for 17.5min, adding EDTA, and continuously grinding until the granularity is less than 1 mm; to treat the inlet SO2The concentration is 2500mg/m3Taking the flue gas as an example, the inlet flue gas temperature is 130 ℃, and the flue gas and the mixed slurry sprayed circularly are subjected to countercurrent contact reaction from bottom to top to remove SO in the flue gas2Controlling the gas speed of the desulfurizing tower to be 25m/s and the liquid-gas ratio to be 9L/m3(ii) a The phosphorite slurry in the mixed slurry is prepared in a preparation tank to have the granularity of at least 90 percent and the granularity of 500 meshes, the solid content is controlled to be 35 weight percent, the mass concentration of the added ammonia water is 15 percent, the mass concentration of the added magnesium oxide is 15 percent, and the pH value is controlled to be largeAt 7; containing SO2The flue gas is contacted and reacted with the sprayed mixed slurry to remove SO in the flue gas2(ii) a Washing the flue gas with slurry, demisting, discharging, and discharging SO2≤30mg/m3The dust concentration is less than or equal to 5mg/m3(ii) a Introducing oxygen into the reacted mixed slurry for reaction, then uniformly stirring, returning to the step S2 for continuously washing the flue gas, and when the solubility of magnesium ammonium phosphate in the mixed slurry reaches a preset requirement, sending the mixed slurry to a crystallizer to produce magnesium ammonium phosphate crystals; the desulfurization efficiency of the flue gas treated by the method can reach more than 95 percent.
Example 6
Grinding the phosphorite slurry for 20min, adding salicylic acid, and further grinding until the particle size is less than 1 mm; to treat the inlet SO2The concentration is 3000mg/m3Taking the flue gas as an example, the inlet flue gas temperature is 140 ℃, and the flue gas and the mixed slurry sprayed circularly are subjected to countercurrent contact reaction from bottom to top to remove SO in the flue gas2Controlling the gas speed of the desulfurizing tower to be 30m/s and the liquid-gas ratio to be 7L/m3(ii) a Blending the phosphorite slurry in the mixed slurry in a blending tank until the granularity is at least 90 percent and the granularity is over 500 meshes, controlling the solid content to be 40 weight percent, controlling the mass concentration of the added ammonia water to be 20 percent, controlling the mass concentration of the added magnesium oxide to be 20 percent, and controlling the pH value to be more than 7; containing SO2The flue gas is contacted and reacted with the sprayed mixed slurry to remove SO in the flue gas2(ii) a Washing the flue gas with slurry, demisting, discharging, and discharging SO2≤30mg/m3The dust concentration is less than or equal to 5mg/m3(ii) a Introducing oxygen into the reacted mixed slurry for reaction, then uniformly stirring, returning to the step S2 for continuously washing the flue gas, and when the solubility of magnesium ammonium phosphate in the mixed slurry reaches a preset requirement, sending the mixed slurry to a crystallizer to produce magnesium ammonium phosphate crystals; the desulfurization efficiency of the flue gas treated by the method can reach more than 95 percent.
Claims (10)
1. A flue gas desulfurization method based on an ammonia-magnesium combined strengthening phosphate rock slurry method is characterized by comprising the following steps:
s1, adding ammonia water and magnesium oxide into the phosphorite slurry to prepare mixed slurry, and controlling the pH value to be more than 7;
s2, containing SO2The flue gas is contacted and reacted with the sprayed mixed slurry to remove SO in the flue gas2；
S3, washing the flue gas by the slurry, demisting and discharging; and introducing oxygen into the reacted mixed slurry for reaction, then uniformly stirring, returning to the step S2 for continuously washing the flue gas, and when the solubility of the magnesium ammonium phosphate in the mixed slurry reaches a preset requirement, sending to a crystallizer to produce magnesium ammonium phosphate crystals.
2. The flue gas desulfurization method based on the magnesium ammonia combined strengthening phosphate rock slurry method according to claim 1, characterized in that before the step of S1, the method further comprises grinding the phosphate rock slurry for 5-30 min, adding an organic acid, and further grinding until the particle size is less than 1mm, wherein the organic acid is citric acid, fumaric acid, EDTA, salicylic acid or tartaric acid.
3. The method for desulfurizing flue gas based on the ammagnesium combined enhanced phosphate slurry process according to claim 1, wherein the particle size of the phosphate slurry is at least 90% passing through 500 meshes.
4. The flue gas desulfurization method based on the ammonia-magnesium combined enhanced phosphate rock slurry method as claimed in claim 1, characterized in that the solid content of the mixed slurry is 30-40 wt%, the mass concentration of ammonia water is 10-20%, and the mass concentration of magnesium oxide is 10-20%.
5. A system for realizing the flue gas desulfurization method based on the ammonia-magnesium combined enhanced phosphate slurry method according to any one of claims 1 to 4, which is characterized by comprising a blending tank (1), a first delivery pump (2), a second delivery pump (3), a circulating tank (4), a desulfurization tower (5), a liquid distributor (6), a demister (7), a water tank (8), a third delivery pump (9), a first stirrer (10), a second stirrer (11) and a discharge pump (12), wherein the blending tank (1) is communicated with the circulating tank (4) through a pipeline and the first delivery pump (2), the bottom of the desulfurization tower (5) is communicated with the circulating tank (4) through a pipeline, the blending tank (1) is provided with the first stirrer (10), the liquid distributor (6) is provided in three numbers, the upper part in the desulfurization tower (5) is arranged in sequence from bottom to top, and the circulating tank (4) is provided with a pipeline, and through second delivery pump (3), communicate with liquid distributor (6), and the pipeline is equipped with the pH detector, circulation groove (4) be equipped with second agitator (11), desulfurizing tower (5) top exhaust port be equipped with defroster (7), liquid distributor (6) top be equipped with spray pipe (13), basin (8) pass through the pipeline, and through third delivery pump (9), communicate with spray pipe (13), desulfurizing tower (5) lower part bin outlet be equipped with discharge pump (12), desulfurizing tower (5) side lower part be equipped with into mouth (14), advance oxygen mouth (15).
6. The system according to claim 5, wherein the desulfurizing tower (5) is a cylindrical desulfurizing tower, the liquid distributor (6) comprises an annular shell (6 a), two partition plates (6 b), an outer toothed ring (6 c), two racks (6 d), a rack chute (6 e), a driving cylinder (6 f), a support frame (6 g), a flexible slurry inlet pipe (6 h), a first slurry spraying head (6 i) and a second slurry spraying head (6 j), the two partition plates (6 b) are arranged on the inner side of the annular shell (6 a) in a cross shape, the inner side of the annular shell (6 a) is divided into four flue gas channels, annular grooves are formed in the desulfurizing tower (5) with the outer side faces opposite to each other in the annular shell (6 a), an opening penetrating through the inner wall of the desulfurizing tower (5) is formed in one section of each annular groove, and the outer toothed ring (6 c) is sleeved on the outer side of the annular shell (6 a), the outer gear ring (6 c) is positioned in the annular groove, the rack (6 d) is positioned on the outer side of the desulfurization tower (5), one section of the rack (6 d) is positioned in the opening, the part, positioned in the opening, of the rack (6 d) is meshed with the teeth of the outer gear ring (6 c), the side surface of the rack (6 d) is in sliding fit with the rack sliding chute (6 e), the support frame (6 g) is arranged at the bottom of the rack sliding chute (6 e), the piston rod of the driving cylinder (6 f) is connected with the end part of the rack (6 d), so that the driving cylinder (6 f) can drive the rack (6 d) to reciprocate in the rack sliding chute (6 e), the first slurry spraying heads (6 i) are provided with a plurality of parts and are respectively arranged at the bottom of the annular shell (6 a), the second slurry spraying heads (6 j) are provided with a plurality of parts and are respectively arranged on two surfaces of the partition plates (6 b), one end of the flexible slurry inlet pipe (6 h) is connected with a joint on the side surface of the desulfurization tower (5), the other end is communicated with the first guniting head (6 i) and the second guniting head (6 j) through a connecting pipeline.
7. The system according to claim 5, characterized in that the bottom of said annular housing (6 a) is inclined inwards.
8. The system according to claim 5, characterized in that the flexible slurry inlet pipe (6 h) is positioned on the top of the annular shell (6 a) and the partition plate (6 b), and the middle part of the flexible slurry inlet pipe (6 h) is arranged on the top of the partition plate (6 b) through a pipeline fixing bracket.
9. The system according to claim 5, characterized in that the slurry inlet end of the connecting pipe is positioned on the top of the annular housing (6 a), and the slurry inlet end of the connecting pipe is connected with the end of the flexible slurry inlet pipe (6 h), and the connecting pipe is respectively positioned in the annular housing (6 a) and the baffle plate (6 b).
10. The system according to claim 5, characterized in that the annular housings (6 a) of two adjacent liquid distributors (6) in the desulfurizing tower (5) rotate in opposite directions.
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