CN119113752A - A low-temperature flue gas desulfurization and denitrification treatment process - Google Patents
A low-temperature flue gas desulfurization and denitrification treatment process Download PDFInfo
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- CN119113752A CN119113752A CN202411247796.0A CN202411247796A CN119113752A CN 119113752 A CN119113752 A CN 119113752A CN 202411247796 A CN202411247796 A CN 202411247796A CN 119113752 A CN119113752 A CN 119113752A
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- flue gas
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- 239000003546 flue gas Substances 0.000 title claims abstract description 105
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 103
- 238000000034 method Methods 0.000 title claims abstract description 42
- 230000008569 process Effects 0.000 title claims abstract description 34
- 238000006477 desulfuration reaction Methods 0.000 title claims abstract description 31
- 230000023556 desulfurization Effects 0.000 title claims abstract description 31
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims abstract description 75
- 239000007788 liquid Substances 0.000 claims abstract description 58
- 238000010521 absorption reaction Methods 0.000 claims abstract description 57
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 57
- 230000003647 oxidation Effects 0.000 claims abstract description 49
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 claims abstract description 48
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims abstract description 46
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 45
- ZCCIPPOKBCJFDN-UHFFFAOYSA-N calcium nitrate Chemical compound [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ZCCIPPOKBCJFDN-UHFFFAOYSA-N 0.000 claims abstract description 42
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 claims abstract description 34
- 239000007800 oxidant agent Substances 0.000 claims abstract description 31
- 230000001590 oxidative effect Effects 0.000 claims abstract description 31
- 239000003623 enhancer Substances 0.000 claims abstract description 19
- 239000002002 slurry Substances 0.000 claims abstract description 9
- 239000013078 crystal Substances 0.000 claims abstract description 7
- 238000001914 filtration Methods 0.000 claims abstract description 5
- 239000000428 dust Substances 0.000 claims description 10
- 229920006395 saturated elastomer Polymers 0.000 claims description 9
- AZQWKYJCGOJGHM-UHFFFAOYSA-N 1,4-benzoquinone Chemical compound O=C1C=CC(=O)C=C1 AZQWKYJCGOJGHM-UHFFFAOYSA-N 0.000 claims description 8
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical class [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 8
- 239000000706 filtrate Substances 0.000 claims description 7
- 150000001412 amines Chemical class 0.000 claims description 6
- 239000007787 solid Substances 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 4
- 230000008719 thickening Effects 0.000 claims description 3
- 230000003009 desulfurizing effect Effects 0.000 claims 4
- 239000006227 byproduct Substances 0.000 abstract description 6
- 239000002131 composite material Substances 0.000 abstract description 3
- 239000012535 impurity Substances 0.000 abstract description 3
- 239000003513 alkali Substances 0.000 description 23
- 150000003839 salts Chemical class 0.000 description 14
- 239000012266 salt solution Substances 0.000 description 11
- 239000000243 solution Substances 0.000 description 10
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 7
- 239000000920 calcium hydroxide Substances 0.000 description 7
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 7
- 239000007791 liquid phase Substances 0.000 description 7
- 239000003638 chemical reducing agent Substances 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 5
- 239000003814 drug Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 229920000877 Melamine resin Polymers 0.000 description 4
- 239000012267 brine Substances 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 4
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 238000006722 reduction reaction Methods 0.000 description 4
- 239000000779 smoke Substances 0.000 description 4
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 4
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 3
- 239000004202 carbamide Substances 0.000 description 3
- 239000000571 coke Substances 0.000 description 3
- 238000002425 crystallisation Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000012065 filter cake Substances 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 150000003568 thioethers Chemical class 0.000 description 3
- ZHJGWYRLJUCMRT-UHFFFAOYSA-N 5-[6-[(4-methylpiperazin-1-yl)methyl]benzimidazol-1-yl]-3-[1-[2-(trifluoromethyl)phenyl]ethoxy]thiophene-2-carboxamide Chemical compound C=1C=CC=C(C(F)(F)F)C=1C(C)OC(=C(S1)C(N)=O)C=C1N(C1=C2)C=NC1=CC=C2CN1CCN(C)CC1 ZHJGWYRLJUCMRT-UHFFFAOYSA-N 0.000 description 2
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000000889 atomisation Methods 0.000 description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 description 2
- 239000013043 chemical agent Substances 0.000 description 2
- 239000003245 coal Substances 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 229960002089 ferrous chloride Drugs 0.000 description 2
- 239000011790 ferrous sulphate Substances 0.000 description 2
- 235000003891 ferrous sulphate Nutrition 0.000 description 2
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 2
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 238000005502 peroxidation Methods 0.000 description 2
- AOHJOMMDDJHIJH-UHFFFAOYSA-N propylenediamine Chemical compound CC(N)CN AOHJOMMDDJHIJH-UHFFFAOYSA-N 0.000 description 2
- KIDHWZJUCRJVML-UHFFFAOYSA-N putrescine Chemical compound NCCCCN KIDHWZJUCRJVML-UHFFFAOYSA-N 0.000 description 2
- 150000003254 radicals Chemical class 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 239000010865 sewage Substances 0.000 description 2
- 230000001502 supplementing effect Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 239000005708 Sodium hypochlorite Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000000536 complexating effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000003337 fertilizer Substances 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000012452 mother liquor Substances 0.000 description 1
- 239000000618 nitrogen fertilizer Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/75—Multi-step processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/60—Simultaneously removing sulfur oxides and nitrogen oxides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/36—Nitrates
- C01F11/38—Preparation with nitric acid or nitrogen oxides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/46—Sulfates
- C01F11/464—Sulfates of Ca from gases containing sulfur oxides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/10—Oxidants
- B01D2251/106—Peroxides
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- Inorganic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biomedical Technology (AREA)
- Geology (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Treating Waste Gases (AREA)
Abstract
本发明公开了一种低温烟气脱硫脱硝处理工艺，涉及烟气脱硫脱硝技术领域。本发明根据排放温度低于150℃的低温烟气氧化脱硝复合脱硫的特点，利用双氧水和氧化增强剂复配的氧化剂对烟气中的二氧化硫及氮氧化物进行氧化，之后利用碱性吸收液进行吸收，副产硫酸钙及硝酸钙；吸收二氧化硫及氮氧化物后的浆液，因硫酸钙和硝酸钙的溶解度差值很大，硫酸钙可直接经过过滤装置生产；对于非饱和水烟气，硝酸钙浆液可利用初期烟气进行除杂并增浓，然后经过降温结晶，进而生产出高纯度的硝酸钙晶体，显著降低了低温烟气脱硫脱硝的成本。
The invention discloses a low-temperature flue gas desulfurization and denitrification treatment process, and relates to the technical field of flue gas desulfurization and denitrification. According to the characteristics of low-temperature flue gas oxidation denitrification composite desulfurization with a discharge temperature below 150°C, the invention uses an oxidant compounded with hydrogen peroxide and an oxidation enhancer to oxidize sulfur dioxide and nitrogen oxides in the flue gas, and then uses an alkaline absorption liquid to absorb them, and produces calcium sulfate and calcium nitrate as by-products; the slurry after absorbing sulfur dioxide and nitrogen oxides can be directly produced through a filtering device because the solubility difference between calcium sulfate and calcium nitrate is very large; for unsaturated water flue gas, the calcium nitrate slurry can be used to remove impurities and increase the concentration of the initial flue gas, and then it is cooled and crystallized to produce high-purity calcium nitrate crystals, which significantly reduces the cost of low-temperature flue gas desulfurization and denitrification.
Description
Technical Field
The invention relates to the technical field of flue gas desulfurization and denitrification, in particular to a low-temperature flue gas desulfurization and denitrification treatment process.
Background
The raw material of the industrial furnace is generally coal, and a large amount of sulfides and nitrogen oxides can be generated in the combustion process of the coal, wherein the sulfides are sulfur dioxide, about 90% of the nitrogen oxides are NO, and the remaining 10% of the nitrogen oxides are mainly NO 2, and if the sulfides and the nitrogen oxides are directly discharged into the atmosphere without treatment, photochemical smog, acid rain and haze can be generated, and an ozone layer can be damaged. Therefore, desulfurization and denitrification treatment of flue gas is an important research problem.
As for the control of nitrogen oxides (NOx), SCR (selective chemical reduction) and SNCR (selective non-chemical reduction), active coke adsorption, oxidation absorption, complex absorption electrochemical reduction, and the like are currently the main methods. The SCR denitration is also called selective catalytic reduction denitration, the reducing agent is NH 3 or urea, NOx in the flue gas can be selectively subjected to chemical reduction reaction, nitrogen and water are finally generated, the flue gas is required to reach high temperature of at least 180 ℃ in the SCR reaction, the industrial kiln is basically subjected to energy-saving design, and the temperature of the flue gas is usually lower than 150 ℃, so that the flue gas is required to be subjected to secondary temperature rise by adopting the SCR denitration. The denitration of SNCR is to select a temperature range from 850 ℃ to 1100 ℃, spray atomized urea solution or ammonia water, treat NOx, generate nitrogen and water, and have the problems of lower efficiency (less than 50%), and exceeding ammonia escape. The active coke denitration method is applied to flue gas treatment of sintering machines of iron and steel enterprises, and mainly utilizes the chemical property of active coke to reduce NO into N 2 under the action of a reducing agent NH 3. The electrochemical denitration method mainly utilizes complexing absorption liquid to absorb NO X in flue gas from the flue gas into liquid phase, then reacts with reducing agent urea and the like rapidly under the action of electric field force, has little temperature requirement on the flue gas, is favorable for absorbing NO at low temperature, but is only remained in a laboratory and a small test stage at present, the timeliness and the absorption efficiency of the denitration medicament are greatly reduced after the operation for a few hours in industrial production, the absorption efficiency is not more than 20%, and the flue gas is difficult to reach the emission standard.
For low temperature flue gas at temperatures below 150 ℃, the oxidation process is the most suitable and economical way to treat. The oxidation method mainly utilizes chemical agents to oxidize and absorb NO X into a liquid phase, and the currently adopted chemical agents mainly comprise strong oxidants such as ozone, hydrogen peroxide, sodium hypochlorite, composite oxidation agents and the like, so that the method has the obvious defects of high reagent consumption and difficult treatment of waste liquid absorbed by denitration property. Therefore, the oxidation absorption process is technically optimized, so that the high-efficiency desulfurization and denitrification of low-temperature flue gas under low cost are particularly necessary.
Disclosure of Invention
The invention aims to provide a low-temperature flue gas desulfurization and denitrification treatment process for solving the problems in the prior art.
In order to achieve the above object, the present invention provides the following solutions:
The invention provides a desulfurization and denitrification treatment process for low-temperature unsaturated water flue gas, which comprises the following steps of:
oxidizing sulfur dioxide and nitrogen oxides in the low-temperature unsaturated water flue gas by using an oxidant, then introducing the oxidized flue gas into an alkaline absorption liquid, and obtaining the desulfurization and denitration flue gas after the alkaline absorption liquid is subjected to absorption treatment;
And filtering the slurry obtained after the alkaline absorption liquid is absorbed to obtain calcium sulfate solid, thickening filtrate by using the low-temperature unsaturated water flue gas, and crystallizing to obtain calcium nitrate crystals.
Further, in the low-temperature unsaturated water flue gas, the content of 2000mg/Nm 3≥NOX is more than or equal to 50mg/Nm 3,2000mg/Nm3 is more than or equal to 20mg/m 3, and the content of dust is less than or equal to 10mg/Nm 3.
Further, the oxidant is a mixture of hydrogen peroxide and an oxidation enhancer, and the alkaline absorption liquid is slurry of calcium oxide, calcium hydroxide or calcium carbonate. More preferably, the mass concentration of the alkaline absorption liquid is more than or equal to 4 percent.
Further, the oxidation enhancer is one or more of organic amine, quinone or ferrous salt with weak reducibility.
Still further, the organic amines include, but are not limited to, melamine, propylene diamine, butylene diamine, acrylamide, and the like, and the ferrous salts include, but are not limited to, ferrous sulfate, ferrous chloride, ferrous nitrate, and organic ferrous EDTA2-Fe salts.
Further, the molar ratio of the hydrogen peroxide to the oxidation enhancer is 1:1.
The invention also provides a low-temperature saturated water flue gas desulfurization and denitrification treatment process, wherein the temperature of the low-temperature saturated water flue gas is less than or equal to 150 ℃, and the desulfurization and denitrification process comprises the following steps of:
oxidizing sulfur dioxide and nitrogen oxides in the low-temperature unsaturated water flue gas by using an oxidant, then introducing the oxidized flue gas into an alkaline absorption liquid, and obtaining the desulfurization and denitration flue gas after the alkaline absorption liquid is subjected to absorption treatment;
And filtering the slurry obtained after the alkaline absorption liquid is absorbed and treated to obtain calcium sulfate solid, and crystallizing the filtrate to obtain calcium nitrate crystals.
Further, in the low-temperature saturated water flue gas, the content of 2000mg/Nm 3≥NOX is more than or equal to 50mg/Nm 3,2000mg/Nm3 is more than or equal to 20mg/m 3, and the content of dust is less than or equal to 10mg/Nm 3.
Further, the oxidant is a mixture of hydrogen peroxide and an oxidation enhancer.
Further, the oxidation enhancer is an organic amine, quinone or ferrous salt.
Still further, the organic amines include, but are not limited to, melamine, propylene diamine, butylene diamine, acrylamide, and the like, and the ferrous salts include, but are not limited to, ferrous sulfate, ferrous chloride, ferrous nitrate, and organic ferrous EDTA2-Fe salts.
Further, the molar ratio of the hydrogen peroxide to the oxidation enhancer is 1:1.
The invention enhances the oxidizing property of the hydrogen peroxide, ensures the oxidizing capability of NO and sulfur dioxide at 20-150 ℃, optimizes the post-treatment process of the acid gas absorbent, and can obtain byproducts of calcium sulfate and calcium nitrate. The byproduct calcium sulfate does not need to be subjected to air oxidation, the purity of the byproduct calcium nitrate can reach more than 99 percent, and the byproduct calcium nitrate can be used as agricultural fertilizer or other industrial purposes, so that the cost of low-temperature flue gas desulfurization and denitrification is obviously reduced, and the theoretical value of the single kg removal cost of NO is lower than 2 yuan.
The invention discloses the following technical effects:
According to the characteristics of low-temperature flue gas oxidation, denitration and composite desulfurization with the discharge temperature lower than 150 ℃, the invention uses the oxidant compounded by the hydrogen peroxide and the oxidation enhancer to oxidize sulfur dioxide and nitrogen oxides in the flue gas, and then uses the alkaline absorption liquid to absorb the sulfur dioxide and the nitrogen oxides in the flue gas, and the process can simultaneously remove the nitrogen oxides and sulfur dioxide in the flue gas and byproducts of calcium sulfate and calcium nitrate; the slurry absorbing sulfur dioxide and nitrogen oxides can be produced by directly passing through a filter device because of the large solubility difference between calcium sulfate and calcium nitrate, and the liquid phase and solid of the calcium nitrate can meet the requirements of agricultural nitrogen fertilizer, meanwhile, the calcium nitrate can be further purified to be used as industrial raw materials, and for unsaturated water flue gas, the calcium nitrate slurry can be subjected to impurity removal and thickening by utilizing initial flue gas and then is crystallized to produce high-purity calcium nitrate crystals, so that the cost of desulfurization and denitration of low-temperature flue gas is obviously reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a low-temperature unsaturated water flue gas desulfurization and denitrification treatment process, wherein a 01-flue gas fan, a 02-salt concentration tower, a 03-sewage pump, a 04-salt solution circulation tank, a 05-concentrated brine circulation pump, a 06-crystallization tank, a 07-centrifuge, a 08-oxidation medicament tank, a 09-oxidation pump, a 10-oxidation absorption tower, a 11-oxidation agent circulation pump, a 12-absorption liquid tank, a 13-absorption liquid circulation pump, a 14-alkaline liquid pump, a 15-powder bin, a 16-conveyor, a 17-alkaline liquid preparation tank and a 18-filter press are adopted.
FIG. 2 is a flow chart of the low-temperature saturated water flue gas desulfurization and denitrification treatment process. Wherein, the device comprises a 01-flue gas fan, a 02-oxidation medicament tank, a 03-oxidation absorption tower, a 04-oxidation pump, a 05-oxidation agent circulating pump, a 06-absorption liquid tank, a 07-absorption liquid circulating pump, a 08-powder bin, a 09-conveyor, a 10-alkali liquor preparation tank, a 11-filter press, a 12-salt concentration device and a 13-alkali liquor pump.
Detailed Description
Various exemplary embodiments of the invention will now be described in detail, which should not be considered as limiting the invention, but rather as more detailed descriptions of certain aspects, features and embodiments of the invention.
It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In addition, for numerical ranges in this disclosure, it is understood that each intermediate value between the upper and lower limits of the ranges is also specifically disclosed. Every smaller range between any stated value or stated range, and any other stated value or intermediate value within the stated range, is also encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.
It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the invention described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from consideration of the specification of the present invention. The specification and examples of the present invention are exemplary only.
As used herein, the terms "comprising," "including," "having," "containing," and the like are intended to be inclusive and mean an inclusion, but not limited to.
Example 1
The flow chart of the desulfurization and denitrification treatment process of the low-temperature unsaturated water flue gas is shown in figure 1. The processing flow is as follows:
The treated flue gas is unsaturated water flue gas of kiln enterprises with flue gas amount of 100000Nm 3/h, the content of nitrogen oxides in the initial flue gas is 320mg/Nm 3, the content of sulfur dioxide is 56mg/Nm 3, the content of dust is 10mg/Nm 3, the water content is 8%, and the temperature is 120 ℃.
1. And the flue gas flow is that the unsaturated water flue gas from the kiln enterprises enters a salt concentration tower 02 after passing through a flue gas fan 01 and is fully mixed with salt solution sprayed by an atomization device at the top of the tower, and in the mixing process, water in the salt solution enters the flue gas to enable the flue gas to become water-rich flue gas, the water content in the salt solution is reduced, the concentration is realized, and meanwhile, the temperature of the water-rich flue gas is controlled to be less than or equal to 80 ℃. And then the flue gas is discharged from the top of the salt concentration tower 02 and enters the oxidation absorption tower 10 to be fully contacted with the oxidant circulated in the tower, and NO and SO 2 in the flue gas are oxidized into high-valence NO X and SO 3. The high-valence NO X and SO 3 fully react with the alkali liquor sprayed in the oxidation absorption tower 10, and the alkali liquor is absorbed by the alkali liquor and then enters the absorption liquid tank 12 to finish the removal of nitrogen oxides and sulfur dioxide in the flue gas, and the treated flue gas is discharged into the atmosphere through the top of the oxidation absorption tower 10.
2. Liquid phase flow:
two circulation sections, namely an oxidant circulation section and an alkali liquor circulation section, are arranged in the oxidation absorption tower 10.
(1) And (3) preparing an oxidant, namely adding hydrogen peroxide into an oxidizing agent tank 08, arranging a metering device in the oxidizing agent tank 08, and adding an oxidation enhancer (melamine) according to the mol ratio of 1:1 to obtain the oxidant. In this state, hydrogen peroxide can form a peroxidation or free radical oxygen state, so that the oxidability of hydrogen peroxide is completely activated, and the reaction temperature is reduced.
(2) The oxidant in the oxidizing agent tank 08 is pumped into the atomization device of the oxidation absorption tower 10 through the oxidant pump 09, fully reacts with NO and SO 2 in the flue gas from the salt concentration tower 02, oxidizes the flue gas into high-valence NO X and SO 3, and the unreacted complete oxidant is recycled in the oxidation absorption tower 10 through the oxidant circulating pump 11. Meanwhile, the circulating liquid after collecting part of the oxidant circulating pump 11 enters the alkali liquor preparation tank 17 for preparing the reference alkali liquor.
(3) The calcium hydroxide in the powder bin 15 is conveyed into an alkali solution preparation tank 17 through a conveyor 16 to prepare a calcium hydroxide turbid liquid with the concentration of 4%, then the calcium hydroxide turbid liquid is conveyed into an absorption liquid tank 12 through an alkali solution pump 14, alkali solution in the absorption tank 12 is pumped into an oxidation absorption tower 10 through an absorption liquid circulating pump 13 to be fully mixed with flue gas for reaction, high-valence NO X and SO 3 contained in the flue gas are absorbed into the liquid phase to react to generate a mixed turbid liquid of calcium sulfate and calcium nitrate, and the mixed turbid liquid is returned into the absorption liquid tank 12 for recycling, SO that the pH value of the circulating liquid is more than or equal to 6.5.
(4) The circulating liquid after collecting part of absorbing liquid circulating pump 13 is filtered by a filter press 18 to remove calcium sulfate, the obtained filtrate enters a salt liquid circulating tank 04, the process of collecting the circulating liquid and the process of supplementing alkali liquid are controlled in linkage, the PH value of the circulating alkali liquid is controlled to be more than or equal to 6.5, and the filter cake of the filter press 18 is delivered or sold after loading calcium sulfate.
(5) The salt solution from the oxidation absorption section filter press 18 enters the salt solution circulating tank 04 of the salt concentration section, and is partially pumped into the salt concentration tower 02 through the concentrated salt solution circulating pump 05 to be fully mixed with the unsaturated water smoke entering from the bottom of the salt concentration tower 02, the heat and mass transfer process occurs in the mixing process, the smoke becomes water-rich smoke, the water in the salt solution enters the smoke, and the salt solution becomes concentrated. The Baume degree is controlled between 55 and 60Be through the cycle times, and the PH value is controlled between 5.5 and 6.5.
(6) And (3) after part of concentrated brine is collected by a circulating pump 05, the brine enters a crystallizing tank 06 and is cooled to 50 ℃, calcium nitrate tetrahydrate is obtained through crystallization, calcium nitrate crystals (purity is 99.8%) are separated out after the crystallization liquid passes through a centrifugal machine 07, and mother liquor returns to the brine circulating tank 04 and is continuously concentrated in a circulating way.
(7) Impurities at the bottom part of the salt concentration tower 02 are sent into an oxidation section filter press 18 through a sewage pump 03 to remove calcium sulfate generated in the salt concentration section.
In the treated flue gas, the nitrogen oxide content is 25mg/Nm 3, the sulfur dioxide content is 2.1mg/Nm 3, the dust content is 3mg/Nm 3, the water content is 8%, and the temperature is 50 ℃. The exhaust gas flow is 100000Nm 3/h.
Comparative example 1
The flue gas conditions were the same as in example 1. The difference is that only hydrogen peroxide is added in the oxidation agent tank 08 and no oxidation enhancer is added.
The results of comparative example 1 show that the nitrogen oxide content is 50mg/Nm 3, the sulfur dioxide content is 5mg/Nm 3, the dust content is 5mg/Nm 3, the water content is 9% and the temperature is 50 ℃. The exhaust gas flow is 100000Nm 3/h.
The hydrogen peroxide consumption of the embodiment 1 is only 17kg/h, the hydrogen peroxide consumption of the comparative embodiment 1 is 48kg/h, and the hydrogen peroxide consumption can be greatly reduced after the oxidation enhancer is added.
Example 2
The flow chart of the desulfurization and denitrification treatment process of the low-temperature saturated water flue gas is shown in fig. 2, and the treatment flow is as follows:
The treated flue gas comes from a high-purity high-whiteness calcium carbonate production enterprise, the productivity is 300t/d, the flue gas volume is 45000Nm 3/h, the nitrogen oxide content in the initial flue gas is 250mg/Nm 3, the sulfur dioxide content is 35mg/Nm 3, the dust content is 18mg/Nm 3, the water content is 17%, and the temperature is 60 ℃.
1. And in the flue gas flow, the saturated water flue gas enters an oxidation absorption tower 03 through a flue gas fan 01, the flue gas is fully contacted with an oxidant circulating in the tower in the oxidation absorption tower 03, and NO and SO 2 in the flue gas are oxidized into high-valence NO X and SO 3. The high-valence NO X and SO 3 fully react with alkali liquid sprayed in the oxidation absorption tower 03, the alkali liquid is absorbed into the absorption liquid tank 06, the removal of nitrogen oxides and sulfur dioxide is completed by the flue gas, and then the flue gas is discharged into an exhaust pipe from the top of the oxidation absorption tower 03 to enter the atmosphere.
2. Liquid phase flow:
two sections of circulation, an oxidant circulation section and an alkali liquor circulation section are arranged in the oxidation absorption tower 03.
(1) And (3) preparing an oxidant, namely adding hydrogen peroxide into an oxidation medicament tank 02, arranging a metering device in the oxidation medicament tank 02, and adding an oxidation enhancer (melamine) according to the mol ratio of 1:1. In this state, hydrogen peroxide can form a peroxidation or free radical oxygen state, so that the oxidability of hydrogen peroxide is completely activated, and the reaction temperature is reduced.
(2) The disposed oxidant is pumped into the oxidation absorption tower 03 by the oxidant pump 04, fully reacts with NO and SO 2 in the flue gas from the kiln, and oxidizes the NO and SO X and SO 3. The unreacted oxidizing agent is recycled in the oxidation absorption tower by an oxidizing agent circulating pump 5. Meanwhile, the circulating liquid after collecting part of the oxidant circulating pump 5 enters the alkali liquor preparation tank 10 for preparing the reference alkali liquor.
(3) The calcium hydroxide in the powder bin 08 is conveyed to the alkali solution preparation tank 10 through the conveyor 09 to be configured into calcium hydroxide turbid liquid with the concentration of 4%, then the calcium hydroxide turbid liquid is conveyed into the absorption liquid tank 06 through the alkali solution pump 13, then the alkali solution is conveyed into the oxidation absorption tower 03 through the absorption liquid circulating pump 07 to be fully mixed with flue gas for reaction, high-valence NO X and SO 3 contained in the flue gas are absorbed and enter the liquid phase for reaction to generate mixed turbid liquid of calcium sulfate and calcium nitrate, and the mixed turbid liquid is returned into the absorption liquid tank 06 for recycling, SO that the PH of the circulating liquid is more than or equal to 6.5.
(4) The circulating liquid after collecting part of absorbing liquid circulating pump 07 is subjected to calcium sulfate removal by a filter press 11 and then enters a salt concentration device 12, and the process of collecting the circulating liquid and the process of supplementing alkali liquid are controlled in a linkage manner, so that the PH value of the circulating alkali liquid is controlled to be more than or equal to 5.5. The filter cake removed by the plate frame is the calcium sulfate filtrate which is the salt solution, and the filter cake is carried out or sold. The filtrate enters a salt concentration device 12, and the salt concentration device 12 selects single effect, multiple effect or MVR to produce anhydrous calcium nitrate by evaporating and crystallizing the salt solution according to the process, or the purity of the anhydrous calcium nitrate produced by evaporating and cooling the crystallized calcium nitrate tetrahydrate can reach more than 99.5 percent.
The treated flue gas contains 32mg/Nm 3 of nitrogen oxide, less than or equal to 3.2mg/Nm 3 of sulfur dioxide, 3mg/Nm 3 of dust, 17% of water and 45 ℃. The flow rate of discharged flue gas is 45000Nm 3/h.
Comparative example 2
The flue gas working conditions are the same as those of the embodiment 2, and the difference is that only hydrogen peroxide is added in the oxidation agent tank 02 and no oxidation enhancer is added.
The results showed that less than 10% of the NO and SO 2 in the oxidation absorber 02 was oxidized to higher NO X and SO 3.
In the treated flue gas, the nitrogen oxide content is 200mg/Nm 3, the sulfur dioxide content is less than or equal to 33mg/Nm 3, the dust content is 3mg/Nm 3, the water content is 17%, and the temperature is 45 ℃.
The above embodiments are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the claims of the present invention without departing from the design spirit of the present invention.
Claims (10)
1. The low-temperature unsaturated water flue gas desulfurization and denitrification treatment process is characterized by comprising the following steps of:
oxidizing sulfur dioxide and nitrogen oxides in the low-temperature unsaturated water flue gas by using an oxidant, then introducing the oxidized flue gas into an alkaline absorption liquid, and obtaining the desulfurization and denitration flue gas after the alkaline absorption liquid is subjected to absorption treatment;
And filtering the slurry obtained after the alkaline absorption liquid is absorbed to obtain calcium sulfate solid, thickening filtrate by using the low-temperature unsaturated water flue gas, and crystallizing to obtain calcium nitrate crystals.
2. The desulfurization and denitrification treatment process for low-temperature unsaturated water flue gas according to claim 1, wherein the content of 2000mg/Nm 3≥NOX, the content of sulfur dioxide, the content of dust and the content of 10mg/Nm 3 are respectively equal to or greater than 50mg/Nm 3,2000mg/Nm3, the content of sulfur dioxide and the content of 3.
3. The process for desulfurizing and denitrating low-temperature unsaturated water flue gas according to claim 1, wherein the oxidant is a mixture of hydrogen peroxide and an oxidation enhancer.
4. The process for desulfurization and denitrification of low-temperature unsaturated water flue gas according to claim 3, wherein the oxidation enhancer is one or more of organic amine, quinone or ferrous salts.
5. The process for desulfurizing and denitrating low-temperature unsaturated water flue gas according to claim 4, wherein the molar ratio of the hydrogen peroxide to the oxidation enhancer is 1:1.
6. The low-temperature saturated water flue gas desulfurization and denitrification treatment process is characterized by comprising the following steps of:
oxidizing sulfur dioxide and nitrogen oxides in the low-temperature unsaturated water flue gas by using an oxidant, then introducing the oxidized flue gas into an alkaline absorption liquid, and obtaining the desulfurization and denitration flue gas after the alkaline absorption liquid is subjected to absorption treatment;
And filtering the slurry obtained after the alkaline absorption liquid is absorbed and treated to obtain calcium sulfate solid, and crystallizing the filtrate to obtain calcium nitrate crystals.
7. The desulfurization and denitrification treatment process for low-temperature saturated water flue gas according to claim 6, wherein the content of 2000mg/Nm 3≥NOX, the content of sulfur dioxide, the content of dust and the content of 10mg/Nm 3 are respectively equal to or more than 50mg/Nm 3,2000mg/Nm3, the content of sulfur dioxide and the content of 3.
8. The process for desulfurizing and denitrating low-temperature saturated water flue gas according to claim 6, wherein the oxidant is a mixture of hydrogen peroxide and an oxidation enhancer.
9. The process for desulfurization and denitrification of low-temperature unsaturated water flue gas according to claim 8, wherein the oxidation enhancer is one or more of organic amine, quinone or ferrous salts.
10. The process for desulfurizing and denitrating low-temperature unsaturated water flue gas according to claim 9, wherein the molar ratio of the hydrogen peroxide to the oxidation enhancer is 1:1.
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