CN116440692A - Wet desulfurization system and method for flue gas carbide slag of coal-fired power plant - Google Patents
Wet desulfurization system and method for flue gas carbide slag of coal-fired power plant Download PDFInfo
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- CN116440692A CN116440692A CN202310330347.1A CN202310330347A CN116440692A CN 116440692 A CN116440692 A CN 116440692A CN 202310330347 A CN202310330347 A CN 202310330347A CN 116440692 A CN116440692 A CN 116440692A
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- 239000002893 slag Substances 0.000 title claims abstract description 237
- 238000006477 desulfuration reaction Methods 0.000 title claims abstract description 157
- 230000023556 desulfurization Effects 0.000 title claims abstract description 157
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 115
- 239000003546 flue gas Substances 0.000 title claims abstract description 115
- 238000000034 method Methods 0.000 title claims abstract description 34
- 239000002002 slurry Substances 0.000 claims abstract description 202
- 230000003009 desulfurizing effect Effects 0.000 claims abstract description 87
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 77
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 claims abstract description 50
- 238000002425 crystallisation Methods 0.000 claims abstract description 41
- 230000008025 crystallization Effects 0.000 claims abstract description 41
- 229910052742 iron Inorganic materials 0.000 claims abstract description 40
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 32
- 238000003756 stirring Methods 0.000 claims abstract description 32
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 32
- 239000011593 sulfur Substances 0.000 claims abstract description 32
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 32
- 239000010440 gypsum Substances 0.000 claims abstract description 29
- 229910052602 gypsum Inorganic materials 0.000 claims abstract description 29
- 238000012216 screening Methods 0.000 claims abstract description 20
- 238000006243 chemical reaction Methods 0.000 claims abstract description 12
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 claims description 46
- 235000019738 Limestone Nutrition 0.000 claims description 36
- 239000006028 limestone Substances 0.000 claims description 36
- 239000005997 Calcium carbide Substances 0.000 claims description 30
- CLZWAWBPWVRRGI-UHFFFAOYSA-N tert-butyl 2-[2-[2-[2-[bis[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]amino]-5-bromophenoxy]ethoxy]-4-methyl-n-[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]anilino]acetate Chemical compound CC1=CC=C(N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)C(OCCOC=2C(=CC=C(Br)C=2)N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)=C1 CLZWAWBPWVRRGI-UHFFFAOYSA-N 0.000 claims description 30
- 230000018044 dehydration Effects 0.000 claims description 28
- 238000006297 dehydration reaction Methods 0.000 claims description 28
- 239000002351 wastewater Substances 0.000 claims description 23
- 238000005189 flocculation Methods 0.000 claims description 21
- 230000016615 flocculation Effects 0.000 claims description 21
- 239000007789 gas Substances 0.000 claims description 15
- 239000010802 sludge Substances 0.000 claims description 14
- 230000003647 oxidation Effects 0.000 claims description 10
- 238000007254 oxidation reaction Methods 0.000 claims description 10
- 238000009826 distribution Methods 0.000 claims description 8
- 239000007787 solid Substances 0.000 claims description 8
- 239000007921 spray Substances 0.000 claims description 8
- 238000010521 absorption reaction Methods 0.000 claims description 7
- 238000007599 discharging Methods 0.000 claims description 7
- 238000006386 neutralization reaction Methods 0.000 claims description 7
- 239000002699 waste material Substances 0.000 claims description 7
- 239000003513 alkali Substances 0.000 claims description 6
- 239000011148 porous material Substances 0.000 claims description 6
- 239000002994 raw material Substances 0.000 claims description 6
- 239000000523 sample Substances 0.000 claims description 6
- 238000005452 bending Methods 0.000 claims description 3
- 238000004064 recycling Methods 0.000 claims description 3
- 239000013078 crystal Substances 0.000 claims description 2
- 239000003245 coal Substances 0.000 claims 1
- 230000003472 neutralizing effect Effects 0.000 claims 1
- 230000001105 regulatory effect Effects 0.000 claims 1
- 238000009776 industrial production Methods 0.000 abstract description 4
- 238000004537 pulping Methods 0.000 abstract description 3
- 239000002245 particle Substances 0.000 description 18
- 230000000694 effects Effects 0.000 description 9
- 230000008901 benefit Effects 0.000 description 8
- 239000007788 liquid Substances 0.000 description 5
- 238000005299 abrasion Methods 0.000 description 4
- 239000011575 calcium Substances 0.000 description 4
- 238000001514 detection method Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000001914 filtration Methods 0.000 description 4
- 239000012535 impurity Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000006096 absorbing agent Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 239000000292 calcium oxide Substances 0.000 description 2
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 210000001503 joint Anatomy 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229920000915 polyvinyl chloride Polymers 0.000 description 2
- 239000004800 polyvinyl chloride Substances 0.000 description 2
- 239000002910 solid waste Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 229910001424 calcium ion Inorganic materials 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- GBAOBIBJACZTNA-UHFFFAOYSA-L calcium sulfite Chemical compound [Ca+2].[O-]S([O-])=O GBAOBIBJACZTNA-UHFFFAOYSA-L 0.000 description 1
- 235000010261 calcium sulphite Nutrition 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- -1 meanwhile Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000036632 reaction speed Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 238000005507 spraying Methods 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
- B01D53/80—Semi-solid phase processes, i.e. by using slurries
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D36/00—Filter circuits or combinations of filters with other separating devices
- B01D36/02—Combinations of filters of different kinds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/48—Sulfur compounds
- B01D53/50—Sulfur oxides
- B01D53/501—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
- B01D53/502—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound characterised by a specific solution or suspension
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C1/00—Magnetic separation
- B03C1/02—Magnetic separation acting directly on the substance being separated
- B03C1/30—Combinations with other devices, not otherwise provided for
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
- B08B3/02—Cleaning by the force of jets or sprays
-
- 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)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Treating Waste Gases (AREA)
Abstract
A wet desulfurization system and method for flue gas carbide slag of a coal-fired power plant, wherein the desulfurization system comprises: the device comprises a filter screen, a drum screen, a vibrating screen, an iron remover, a carbide slag slurry pool, a desulfurizing tower, a calcium sulfate crystallization pool and a disc type dehydrator. The method comprises the following steps: (1) The carbide slag is filtered by a filter screen, a drum screen and a vibrating screen in sequence to remove coarse slag, and then the fine slag is sent into an iron remover to remove iron, so as to obtain carbide screening slag; (2) Sending into a carbide slag slurry pool, adding water, stirring and pulping to obtain carbide slag slurry; (3) Sending the sulfur-containing flue gas into the top of the desulfurizing tower, sending the sulfur-containing flue gas into the middle of the desulfurizing tower, sending air into the lower part of the desulfurizing tower, and carrying out pulse stirring reaction; (4) And (3) circulating the carbide slag desulfurization slurry to the top of a desulfurization tower, or partially conveying the carbide slag desulfurization slurry into a calcium sulfate crystallization pond, crystallizing and dehydrating to obtain dehydrated gypsum. The concentration of carbide slag slurry in the desulfurization system is stable, the desulfurization efficiency is high and stable, and the desulfurization tower is not easy to scale. The method is simple, low in cost and suitable for industrial production.
Description
Technical Field
The invention relates to a desulfurization system and method, in particular to a wet desulfurization system and method for flue gas carbide slag of a coal-fired power plant.
Background
The flue gas of the coal-fired boiler of the thermal power plant with the concentration of more than 80 percent adopts a limestone wet desulphurization process. The desulfurization slurry and the oxidation slurry are completed in one pool, and the primary byproduct calcium sulfite can be oxidized into a gypsum byproduct with better dehydration, however, the desulfurization tower is easy to scale, and the desulfurization effect is unstable.
The carbide slag is industrial waste slag generated after the acetylene gas is obtained by hydrolyzing the carbide, and because the carbide slag contains a large amount of calcium oxide and silicon dioxide, the carbide slag not only occupies a space to be piled up, but also has certain hidden danger of safety and environmental pollution. Therefore, in recent years, the use of carbide slag for desulfurization has been attempted. However, when the carbide slag is applied to the desulfurization process, the carbide slag raw material is dissolved, the concentration of the carbide slag slurry is unstable due to different sizes of particles, larger particles are not completely dissolved, and when the carbide slag slurry is continuously used for flue gas desulfurization, the problem that the concentration of sulfur dioxide in the desulfurization flue gas is higher and higher can occur, and meanwhile, the problem of easy scaling exists in the desulfurization process in the desulfurization tower.
In summary, it is highly desirable to find a wet desulfurization system and method for flue gas carbide slag of a coal-fired power plant, which has the advantages of stable concentration of carbide slag slurry, high and stable desulfurization efficiency, difficult scaling of a desulfurization tower, simple process and low cost, and is suitable for industrial production.
Disclosure of Invention
The invention aims to solve the technical problems of overcoming the defects in the prior art and providing the wet desulfurization system for the flue gas carbide slag of the coal-fired power plant, which has the advantages of stable concentration of the carbide slag slurry, high and stable desulfurization efficiency and difficult scaling of a desulfurization tower.
The invention further aims to solve the technical problems of overcoming the defects in the prior art and providing the wet desulfurization method for the flue gas carbide slag of the coal-fired power plant, which has the advantages of simple process and low cost and is suitable for industrial production.
The invention provides a wet desulfurization system for flue gas carbide slag of a coal-fired power plant, which comprises the following components: the device comprises a filter screen, a drum screen, a vibrating screen, an iron remover, a carbide slag slurry pool, a desulfurizing tower, a calcium sulfate crystallization pool and a disc dehydrator; fine slag of the carbide slag raw material after being screened by a filter screen is sent to a rotary screen; fine slag in the rotary screen is sent to a vibrating screen, fine slag screened by the vibrating screen is sent to an iron remover, and calcium carbide screening slag removed from the iron remover is sent to a calcium carbide slag slurry pool; the carbide slag slurry pool is connected with the top of the desulfurizing tower; the sulfur-containing flue gas is sent into the middle part of the desulfurizing tower and is discharged from the top, and the air is sent into the lower part of the desulfurizing tower 6 and is discharged from the top; the carbide slag desulfurization slurry in the desulfurization tower is circulated to the top of the desulfurization tower, or the carbide slag desulfurization slurry discharged from the lower part of the desulfurization tower is sent into a calcium sulfate crystallization pond for crystallization, and the crystallized slurry enters a disc type dehydrator for dehydration.
Preferably, the wastewater generated by the calcium sulfate crystallization tank and the disc type dehydrator is sent to an electric flocculation treatment tank for treatment.
Preferably, the limestone slurry tank is connected in parallel with the carbide slag slurry tank and is connected with the top of the desulfurizing tower.
Preferably, the carbide slag slurry tank and the limestone slurry tank are respectively provided with a stirring slurry device.
Preferably, slurry circulating pumps are arranged between the carbide slag slurry tank and the limestone slurry tank and between the lower part and the top of the desulfurizing tower, and a flow rate valve is arranged on the output pipeline.
Preferably, the pore diameter of the filter screen is 180-240 μm. The filter screen can leave larger carbide slag particles above the filter screen, and only smaller particles are allowed to pass through the pores of the filter screen, so that the screening of carbide slag is realized.
Preferably, the screen aperture of the drum screen is 70-100 μm. The carbide slag is often mixed with particles with various particle sizes, and the mesh size of the rotary screen can be adjusted according to the sizes and characteristics of different carbide slag particles so as to separate different carbide slag particles.
Preferably, the sieve pore diameter of the vibrating sieve is 50-65 μm. And finally, the carbide slag with proper particle size is screened out through a vibrating screen, so that pulping is facilitated.
Preferably, the height-to-diameter ratio of the desulfurizing tower is 3-5:1.
Preferably, one side of the top of the desulfurizing tower is provided with a slurry inlet pipe, and the upper end of the slurry inlet pipe is in butt joint with the lower ends of the output pipelines of the carbide slag slurry tank and the limestone slurry tank.
Preferably, a flue gas inlet pipe is arranged in the middle of the desulfurization tower.
Preferably, the lower part of the desulfurizing tower is provided with a desulfurizing slurry output pipe which is respectively connected with a slurry inlet pipe and a calcium sulfate crystallization pond.
Preferably, a desulfurization flue gas discharge pipe is arranged in the middle of the top end of the desulfurization tower.
Preferably, a display panel is arranged in the middle of the desulfurizing tower.
Preferably, the display panel is electrically connected with a temperature probe and a pH value probe in the desulfurizing tower.
Preferably, an axial flow oxidation fan is arranged at the lower part of the desulfurization tower, and a gas distribution pipe is arranged at the part extending into the desulfurization tower.
Preferably, a pulse pump is arranged at the bottom of the inner cavity of the desulfurizing tower.
Preferably, the slurry inlet pipe is provided with a downward spray header at the bending part of the tail end positioned in the middle of the top of the inner cavity of the desulfurizing tower.
Preferably, a beam waist-shaped flue gas demister with wide upper and lower ends and narrow middle is fixedly arranged in the inner cavity of the desulfurizing tower below the spray header.
Preferably, the middle part of flue gas defroster is the through-hole, and through-hole department is equipped with annular distribution's spiral-flow corrugated plate, and the spiral is equipped with the scale removal guiding gutter on the inner chamber lateral wall of flue gas defroster upper end.
The technical scheme adopted by the invention for further solving the technical problems is as follows: a wet desulfurization method for flue gas carbide slag of a coal-fired power plant comprises the following steps:
(1) The calcium carbide slag is filtered by a filter screen, a rotary screen and a vibrating screen in sequence to remove coarse slag, and the obtained fine slag is sent to an iron remover to remove iron so as to obtain calcium carbide screening slag;
(2) Feeding the calcium carbide screening slag obtained in the step (1) into a calcium carbide slag slurry pond, adding water, stirring and slurrying to obtain calcium carbide slag slurry;
(3) Sending the carbide slag slurry obtained in the step (2) to the top of a desulfurization tower, sending sulfur-containing flue gas to the middle of the desulfurization tower, sending air to the lower part of the desulfurization tower, and carrying out pulse stirring reaction in the desulfurization tower to obtain carbide slag desulfurization slurry and discharging desulfurization flue gas;
(4) And (3) recycling the carbide slag desulfurization slurry obtained in the step (3) to the top of the desulfurization tower, or partially feeding the carbide slag desulfurization slurry into a calcium sulfate crystallization pond, crystallizing, and dehydrating to obtain dehydrated gypsum.
Preferably, in the step (1), the main components and mass fractions of the carbide slag are as follows: caO 80-95%, siO 2 2～8%，Fe 2 O 3 0.5 to 1.5 percent, and the total mass fraction is less than or equal to 100 percent. The carbide slag used in the invention is derived from carbide slag solid waste generated in the polyvinyl chloride production process. CaO contained in carbide slag generates a large amount of Ca (OH) with strong alkalinity after slurrying 2 Is a good sulfur dioxide absorbent, and the test result shows that the desulfurization capability of the carbide slag is higher than that of the commercial Ca (OH) 2 20% higher, and the product cost is only the commercial Ca (OH) 2 One third of (3).
Preferably, in the step (1), the magnetic field strength of the iron removal is 1500-2200 kA/m. The iron-containing components in the carbide slag can be removed through iron removal, so that the abrasion of the iron-containing components to desulfurization equipment is reduced.
Preferably, in the step (2), the mass ratio of water to the calcium carbide screening slag is 2.2-3.6:1 (more preferably 2.3-3.0:1). When the water material is relatively low, the slurry has higher viscosity and poorer fluidity, and is not beneficial to the follow-up desulfurization reaction; when the water material is higher, the slurry viscosity is lower, the fluidity is better, and the slurry deposition is easy to cause.
Preferably, in the step (2), the rotation speed of stirring and slurrying is 200-400 rpm, and the time is 1-3 h. In the stirring process, carbide slag particles interact with water molecules to form a uniformly dispersed mixture of carbide slag particles and water molecules, namely carbide slag slurry. Specifically, the principle of the carbide slag slurry stirring and pulping comprises the following aspects: 1) And (3) dispersing carbide slag particles: during the stirring process, the mechanical energy causes carbide slag to be formedThe particles are uniformly dispersed, so that aggregation and accumulation of the particles are avoided; in addition, the stirring can damage the crust layer and the bonding substance on the surface of the carbide slag particles, so that the surface area and the reaction rate of the particles are increased; 2) Water molecule dissolution: the stirring can also lead water molecules to contact with the surfaces of carbide slag particles, and lead the water molecules to have ion exchange reaction with calcium ions on the surfaces of the carbide slag, so as to dissolve out Ca 2+ Ions and OH - Ions to form a calcium hydroxide slurry; 3) Stirring speed adjustment: in the process of stirring and slurrying carbide slag slurry, if the stirring speed is too high, the viscosity of the slurry is reduced, and if the stirring speed is too low, the dispersibility and stability of the slurry are affected.
Preferably, in step (3), the carbide slag slurry flow rate t/h=e×sulfur-containing flue gas flow rate m 3 Concentration of sulfur dioxide in sulfur-containing flue gas mg/m 3 *10 -9 Wherein e=3.2 to 4.7 (more preferably 3.8 to 4.6), and the flow rate of the carbide slag slurry is adjusted within the E value range so that the pH value in the absorber slurry is 4.2 to 4.8. The flow rate of the carbide slag slurry depends on the content of sulfur dioxide in the flue gas, the flow rate of the flue gas, the concentration of the carbide slag in the carbide slag slurry (parameter E) and other factors. Compared with the conventional limestone-gypsum wet method, the carbide slag-gypsum method has the advantages of low liquid-gas ratio, high desulfurization reaction speed and high desulfurization efficiency.
Preferably, in the step (3), the flow rate of the sulfur-containing flue gas is 5 ten thousand to 200 ten thousand m 3 And/h. The treatment flue gas amount is influenced by the selected size of the absorption tower, and the desulfurization efficiency is influenced if the treatment flue gas amount is too large.
Preferably, in the step (3), the concentration of sulfur dioxide in the sulfur-containing flue gas is 500-5000 mg/m 3 . The sulfur-containing flue gas comes from a coal-fired power plant, wherein the too high concentration of sulfur dioxide can lead to the too high concentration of sulfur dioxide in the desulfurization flue gas, and the sulfur-containing flue gas is difficult to reach the emission standard.
Preferably, in the step (3), the flow rate of the pulse pump for the pulse stirring reaction is 2000-5000 m 3 And/h. The pulse pump can reduce the abrasion of carbide slag impurities to equipment. If the pulse pump flow is too low, slurry deposition can occur, and if the pulse pump flow is too high, power consumption can be too high.
Preferably, in the step (3), the air is introduced at a flow rate m 3 H=sulfur-containing flue gas flow m 3 Concentration of sulfur dioxide in sulfur-containing flue gas mg/m 3 *10 -6 *0.25/(k*0.2315kg/m 3 ) Wherein k=0.18 to 0.28. Wherein 0.25 means that 0.25kg of oxygen is required for oxidizing 1kg of sulfur dioxide, and k means the oxidation air utilization ratio of 0.2315 kg/m 3 Represents 1m 3 The air contained 0.2315kg of oxygen.
Preferably, in the step (3), when the concentration of sulfur dioxide in the desulfurized flue gas is more than or equal to 60mg/m 3 Or when the water content of the dehydrated gypsum is more than or equal to 15%, limestone slurry is added into a desulfurization tower until the concentration of sulfur dioxide in the desulfurization flue gas is less than 30mg/m 3 Or the water content of the dehydrated gypsum is less than 15 percent. The purpose of the addition is to stabilize the pH of the absorber slurry.
Preferably, the flow rate of the limestone slurry is 0.1 to 0.4 times (more preferably 0.20 to 0.35 times) the flow rate of the carbide slag slurry.
Preferably, the density of the limestone slurry is 1180-1250 kg/m 3 . The pH value of the slurry in the absorption tower can be effectively controlled under the density of the limestone slurry.
Preferably, in the step (4), the sum of the circulating flow rate of the carbide slag desulfurization slurry, the fresh carbide slag slurry flow rate and the limestone slurry flow rate and the liquid-gas ratio L/m of the sulfur-containing flue gas 3 More preferably from 10 to 20).
Preferably, in the step (4), the flow rate of the carbide slag desulfurization slurry fed into the calcium sulfate crystallization tank is 1.01-1.20 times of the sum of the flow rate of the fresh carbide slag slurry and the flow rate of the limestone slurry;
preferably, in the step (4), the pH of the crystals is 4.2 to 4.8.
Preferably, in the step (4), the solid content of the gypsum slurry before dehydration is 25 to 40%, and the water content of the dehydrated gypsum is 5 to 14%. If the solid content of the gypsum slurry before dehydration is too low, the dehydration effect is poor, and the water content of the dehydrated gypsum is high; if the solids content of the gypsum slurry before dewatering is too high, the dewatering speed is affected, and even the equipment may be blocked.
Preferably, in the step (4), wastewater generated by crystallization and dehydration is subjected to electric flocculation neutralization treatment.
Preferably, the electric flocculation neutralization treatment specifically comprises: firstly, waste water produced by crystallization and dehydration is adjusted to pH value of 6.5-7.5 by waste alkali liquor, then electric flocculation is carried out, and after sludge and waste water are separated, the sludge enters a disc type dehydrator again for dehydration. When the pH value is in the range of 6.5-7.5, the flocculation effect is optimal.
The beneficial effects of the invention are as follows:
(1) According to the desulfurization system, through three layers of carbide slag raw material screening, the filter screen, the rotary screen and the vibrating screen can remove large particle impurities in carbide slag, meanwhile, iron is removed through the iron remover, so that carbide slag dissolved in a carbide slag slurry pond is guaranteed to be small slag, the dissolution efficiency is improved, stable limestone solution concentration is obtained, abrasion and blockage of impurities to equipment and pipelines in a subsequent process can be reduced, the service life of the equipment is prolonged, and the purity of carbide slag slurry is also improved;
(2) The design of the flue gas demister in the desulfurization tower of the desulfurization system ensures that atomized sprayed slurry can form an atomization area above the cyclone corrugated plate, so that the passing flue gas can be subjected to mixed treatment, the liquefied flue gas can flow downwards along the cyclone corrugated plate and flow back into the slurry at the bottom of the tower, and the descaling guide groove can ensure that sprayed liquid is subjected to directional cyclone, so that dirt attached to the cyclone corrugated plate is washed, and the effect of automatic descaling is realized;
(3) The method has the advantages that the concentration of the carbide slag slurry is stable, the desulfurization efficiency can reach 99.5 percent, the desulfurization tower is not easy to scale;
(4) The method of the invention adopts carbide slag to replace limestone for flue gas desulfurization, has simple process, can reduce the desulfurization operation cost, has good economic benefit, environmental benefit and social benefit, and is suitable for industrial production.
Drawings
FIG. 1 is a schematic flow diagram of a wet desulfurization system for flue gas carbide slag in coal-fired power plants according to embodiments 1 to 3 of the present invention;
FIG. 2 is a schematic view showing an axial view of the upper right front side of a desulfurizing tower in the wet desulfurization system for flue gas carbide slag of coal-fired power plants according to embodiments 1 to 3 of the present invention;
FIG. 3 is a schematic view showing the structure of the lower right front side of a desulfurizing tower in the wet desulfurization system for flue gas carbide slag in coal-fired power plants according to examples 1 to 3 of the present invention;
FIG. 4 is a schematic diagram of an axial view of an upward movement state of an upper half part of a desulfurizing tower in a wet desulfurization system for flue gas carbide slag in a coal-fired power plant according to embodiments 1 to 3 of the present invention;
FIG. 5 is an enlarged schematic view of the portion A of FIG. 4;
FIG. 6 is a schematic diagram showing the structure of the lower shaft of the upper half part of a desulfurizing tower in the wet desulfurization system of the flue gas carbide slag of the coal-fired power plant in embodiments 1 to 3 of the invention;
FIG. 7 is a schematic diagram of an isometric view of a portion of a flue gas demister in a wet flue gas carbide slag desulfurization system for coal-fired power plants according to embodiments 1 to 3 of the present invention;
list of reference numerals:
1. a filter screen; 2. a drum screen; 3. a vibrating screen; 4. an iron remover; 5. a carbide slag slurry pool; 6. a desulfurizing tower; 601. feeding slurry into a pipe; 60101. a spray header; 602. a flue gas inlet pipe; 603. a desulphurized slurry output pipe; 604. a desulfurization flue gas discharge pipe; 605. a display panel; 606. an axial flow oxidation fan; 607. a pulse pump; 608. a flue gas demister; 60801. a rotational flow type corrugated plate; 60802. descaling diversion trench; 7. a calcium sulfate crystallization pond; 8. a disc dehydrator; 9. an electric flocculation treatment tank; 10. limestone slurry tank.
Detailed Description
The invention is further described below with reference to examples and figures.
The carbide slag used in the embodiment of the invention is derived from carbide slag solid waste generated in the polyvinyl chloride production process, and the main components and mass fractions of the carbide slag are as follows: caO 87.28%, siO 2 5.81%，Fe 2 O 3 0.85%; the materials or chemicals used in the examples of the present invention, unless otherwise specified, were obtained by conventional commercial means.
Examples 1-3 of wet desulfurization system for flue gas carbide slag of coal-fired power plant
As shown in fig. 1 to 7, a wet desulfurization system for flue gas carbide slag of a coal-fired power plant comprises: the device comprises a filter screen 1, a rotary screen 2, a vibrating screen 3, an iron remover 4, a carbide slag slurry pool 5, a desulfurizing tower 6, a calcium sulfate crystallization pool 7 and a disc dehydrator 8; fine slag of the carbide slag raw material screened by the filter screen 1 is sent to the rotary screen 2; fine slag in the rotary screen 2 is sent to a vibrating screen 3, fine slag screened by the vibrating screen 3 is sent to an iron remover 4, and calcium carbide screening slag removed by iron in the iron remover 4 is sent to a calcium carbide slag slurry pool 5; the carbide slag slurry pool 5 is connected with the top of the desulfurizing tower 6; the sulfur-containing flue gas is sent into the middle part of the desulfurizing tower 6 and is discharged from the top, and the air is sent into the lower part of the desulfurizing tower 6 and is discharged from the top; the carbide slag desulfurization slurry in the desulfurization tower 6 is circulated to the top of the desulfurization tower 6, or the carbide slag desulfurization slurry discharged from the lower part of the desulfurization tower 6 is sent into a calcium sulfate crystallization pond 7 for crystallization, and the crystallized slurry enters a disc dehydrator 8 for dehydration.
Further, the wastewater generated by the calcium sulfate crystallization pond 7 and the disc dehydrator 8 is sent to an electric flocculation treatment pond 9 for treatment; the limestone slurry tank 10 is connected with the carbide slag slurry tank 5 in parallel and is connected with the top of the desulfurizing tower 6; the carbide slag slurry tank 5 and the limestone slurry tank 10 are respectively provided with a stirring slurry device; slurry circulating pumps are arranged between the carbide slag slurry tank 5 and the limestone slurry tank 10 and the desulfurizing tower 6 and between the lower part and the top of the desulfurizing tower 6, and a flow rate valve is arranged on an output pipeline. For ensuring the desulfurization effect of the carbide slag, when the desulfurization effect of the carbide slag is not good, the limestone slurry tank 10 can be immediately used to improve the desulfurization effect.
Wherein the pore diameter of the filter screen 1 is 200 μm; the aperture of the filter screen of the rotary screen 2 is 80 mu m; the screen aperture of the vibrating screen 3 is 60 μm.
Wherein, the height-diameter ratio of the desulfurizing tower 6 is 4:1; a slurry inlet pipe 601 is arranged on one side of the top of the desulfurizing tower 6, and the upper end of the slurry inlet pipe 601 is in butt joint with the lower ends of the output pipelines of the carbide slag slurry tank 5 and the limestone slurry tank 10; a flue gas inlet pipe 602 is arranged in the middle of the desulfurization tower 6; the lower part of the desulfurizing tower 6 is provided with a desulfurizing slurry output pipe 603 which is respectively connected with a slurry inlet pipe 601 and a calcium sulfate crystallization pond 7; a desulfurization flue gas discharge pipe 604 is arranged in the middle of the top end of the desulfurization tower 6; a display panel 605 is arranged in the middle of the desulfurizing tower 6; the display panel 605 is electrically connected with the temperature probe and the pH value probe in the desulfurizing tower 6 and is used for observing the conditions of components in the tower in real time; an axial-flow oxidation fan 606 is arranged at the lower part of the desulfurizing tower 6, and the part extending into the desulfurizing tower 6 is a gas distribution pipe; the bottom of the inner cavity of the desulfurizing tower 6 is provided with a pulse pump 607 which can be used for stirring slurry.
Wherein, the tail end bending part of the slurry inlet pipe 601 positioned in the middle of the top of the inner cavity of the desulfurizing tower 6 is provided with a downward spray header 60101 for atomizing and spraying the slurry; a beam waist-shaped flue gas demister 608 with wide upper and lower ends and narrow middle is fixedly arranged in the inner cavity of the desulfurizing tower 6 below the spray header 60101; the middle part of flue gas defroster 608 is the through-hole, through-hole department is equipped with annular distributed spiral-flow type buckled plate 60801, spiral is equipped with scale removal guiding gutter 60802 on the inner chamber lateral wall of flue gas defroster 608 upper end, the thick liquid that the atomizing sprayed can form the atomizing area above spiral-flow type buckled plate 60801 for the flue gas that passes through can carry out the hybrid treatment, and the flue gas after the liquefaction can follow spiral-flow type buckled plate 60801 and flow down, in the thick liquid of backward flow to tower bottom, and scale removal guiding gutter 60802 can make spray the directional whirl of liquid, thereby erode the dirt that adheres to on the spiral-flow type buckled plate 60801, realize automatic descaling effect.
Specific use and action of the embodiment: in the wet desulfurization system for the carbide slag in the flue gas of the coal-fired power plant, after the carbide slag raw material is screened by a filter screen 1, the small slag is sent to a rotary screen 2, waste slag is discharged, the small slag screened by the rotary screen 2 is sent to a vibrating screen 3, the small slag screened by the vibrating screen 3 is sent to an iron remover 4 again, the iron slag is removed, so that the abrasion to subsequent desulfurization equipment is reduced, the small slag removed by the iron remover 4 is sent to a carbide slag slurry pool 5, and water is added for stirring and slurrying; feeding carbide slag slurry in the carbide slag slurry pond 5 into the top of a desulfurizing tower 6, feeding sulfur-containing flue gas into the middle of the desulfurizing tower 6, feeding air into the lower part of the desulfurizing tower 6, discharging the desulfurizing flue gas from the top of the desulfurizing tower 6 after desulfurization, discharging carbide slag desulfurizing slurry from the lower part of the desulfurizing tower 6, circulating to the top of the desulfurizing tower 6, or partially feeding into a calcium sulfate crystallization pond 7 for crystallization, and feeding the crystallized slurry into a disc-type dehydration deviceThe water machine 8 dewaters. The wastewater generated by the calcium sulfate crystallization pond 7 and the disc type dehydrator 8 can be sent to the electric flocculation treatment pond 9 for treatment, and after the sludge in the electric flocculation treatment pond 9 is separated from the wastewater, the sludge is sent to the disc type dehydrator 8 again for dehydration. When the concentration of sulfur dioxide in the desulfurization flue gas is more than or equal to 60mg/m 3 Or when the water content of the dehydrated gypsum is more than or equal to 15%, the limestone slurry in the limestone slurry tank 10 is sent to the top of the desulfurizing tower 6.
Wet desulfurization method for flue gas carbide slag of coal-fired power plant example 1
(1) Filtering 10t carbide slag sequentially by a filter screen, a rotary screen and a vibrating screen to remove coarse slag, and then sending the obtained fine slag into an iron remover to remove iron under the magnetic field strength of 1800kA/m to obtain 9.9t carbide screening slag;
(2) Feeding 9.9t of calcium carbide screening slag obtained in the step (1) into a calcium carbide slag slurry pool, adding 24t of water, and stirring and slurrying for 2 hours at the rotating speed of 300rpm to obtain calcium carbide slag slurry;
(3) The carbide slag slurry obtained in the step (2) is mixed with a flow rate of 10t/h (the flow rate of the carbide slag slurry t/h=4.43 x 1137322m 3 /h*1985mg/m 3 *10 -9 The pH value in the slurry of the absorption tower is controlled to be 4.6, and the slurry is sent to the top of a desulfurizing tower, and sulfur-containing flue gas (the concentration is 1985 mg/m) 3 ) At a flow rate of 1137322m 3 Delivering the air into the middle part of a desulfurizing tower, and in the desulfurizing tower, an axial flow type oxidation fan delivers the air with the flow rate of 12190m through a gas distribution pipe 3 /h (air flow rate m) 3 /h=1137322m 3 /h*1985mg/m 3 *10 -6 *0.25/(0.2*0.2315kg/m 3 ) Feeding into the lower part of desulfurizing tower at pulse pump flow rate of 4000m 3 And (3) at the step (h), carrying out pulse stirring reaction to obtain carbide slag desulfurization slurry and discharging desulfurization flue gas;
(4) Circulating the carbide slag desulfurization slurry obtained in the step (3) to the top of a desulfurization tower (the sum of the flow of the carbide slag desulfurization slurry and the flow of the fresh carbide slag slurry, and the liquid-gas ratio L/m of sulfur-containing flue gas) 3 20), and feeding into calcium sulfate crystallization pond at flow rate of 11t/h, crystallizing at pH value of 4.6, dewatering gypsum slurry (solid content of 35.2%) to water content of 11.8% by disc dehydrator to obtain dewatered stoneAnd (5) paste.
In the step (4), wastewater generated by crystallization and dehydration is subjected to electric flocculation neutralization treatment, which comprises the following steps: the waste water produced by crystallization and dehydration is firstly adjusted to pH value of 7.0 by using waste alkali liquor of a power plant, then electric flocculation is carried out, and after the sludge and the waste water are separated, the sludge is sent into a disc type dehydrator again for dehydration.
Through detection, the concentration of sulfur dioxide in the desulfurization flue gas discharged in the step (3) is 10mg/m 3 The desulfurization rate was 99.5%.
Wet desulfurization method for flue gas carbide slag of coal-fired power plant example 2
(1) Filtering 12t carbide slag sequentially by a filter screen, a rotary screen and a vibrating screen to remove coarse slag, and then sending the obtained fine slag into an iron remover to remove iron under the magnetic field strength of 2000kA/m to obtain 11.88t carbide screening slag;
(2) Feeding 11.88t calcium carbide screening slag obtained in the step (1) into a calcium carbide slag slurry pool, adding 33t water, and stirring and slurrying for 1.5 hours at the rotating speed of 400rpm to obtain calcium carbide slag slurry;
(3) The carbide slag slurry obtained in the step (2) is mixed with a flow rate of 11t/h (the flow rate of the carbide slag slurry t/h=4.3 x 1536732 m) 3 /h*1667mg/m 3 *10 -9 The pH value in the slurry of the absorption tower is controlled to be 4.4, and the slurry is sent to the top of a desulfurizing tower, and sulfur-containing flue gas (the concentration is 1667 mg/m) 3 ) At a flow rate of 1536732m 3 Delivering the mixture/h into the middle part of a desulfurizing tower, and in the desulfurizing tower, an axial flow type oxidation fan is used for leading air to flow 12575m through a gas distribution pipe 3 /h (air flow rate m) 3 /h=1536732m 3 /h*1667mg/m 3 *10 -6 *0.25/(0.22*0.2315kg/m 3 ) Is sent to the lower part of the desulfurizing tower, and the flow rate of the pulse pump is 4500m 3 And (3) at the step (h), carrying out pulse stirring reaction to obtain carbide slag desulfurization slurry and discharging desulfurization flue gas;
when the concentration of sulfur dioxide in the desulfurization flue gas is more than or equal to 60mg/m 3 When the desulfurization tower was charged with limestone slurry 3t/h (density 1200 kg/m) 3 ) The concentration of sulfur dioxide in the desulfurization flue gas is less than 30mg/m 3 ；
(4) Recycling the carbide slag desulfurization slurry obtained in the step (3) to the top of the desulfurization tower(the sum of the flow rate of the carbide slag desulfurization slurry circulation, the flow rate of the fresh carbide slag slurry and the flow rate of the limestone slurry, and the liquid-gas ratio L/m of the sulfur-containing flue gas) 3 16) and partially feeding the mixture into a calcium sulfate crystallization tank at a flow rate of 12t/h (15.5 t/h when limestone slurry is added), crystallizing at a pH value of 4.4, and dehydrating the gypsum slurry (solid content of 35.2%) to a water content of 11.7% by a disc dehydrator to obtain dehydrated gypsum.
In the step (4), wastewater generated by crystallization and dehydration is subjected to electric flocculation neutralization treatment, which comprises the following steps: the waste water produced by crystallization and dehydration is firstly adjusted to pH value of 7.0 by using waste alkali liquor of a power plant, then electric flocculation is carried out, and after the sludge and the waste water are separated, the sludge is sent into a disc type dehydrator again for dehydration.
Through detection, the concentration of sulfur dioxide in the desulfurization flue gas discharged in the step (3) is 15mg/m 3 The desulfurization rate was 99.1%.
Wet desulfurization method for flue gas carbide slag of coal-fired power plant, example 3
(1) Filtering 8.2t carbide slag sequentially by a filter screen, a rotary screen and a vibrating screen to remove coarse slag, and then sending the obtained fine slag into an iron remover to remove iron under the magnetic field strength of 1500kA/m to obtain 8.1t carbide screening slag;
(2) Feeding 8.1t of calcium carbide screening slag obtained in the step (1) into a calcium carbide slag slurry pool, adding 20t of water, and stirring and slurrying for 2.5 hours at the rotating speed of 300rpm to obtain calcium carbide slag slurry;
(3) The carbide slag slurry obtained in the step (2) is mixed with a flow rate of 5.46t/h (the flow rate of the carbide slag slurry t/h=4.2 x 856322m 3 /h*1519mg/m 3 *10 -9 The pH value in the slurry of the absorption tower is controlled to be 4.6, and the slurry is sent to the top of a desulfurizing tower, and sulfur-containing flue gas (the concentration is 1519 mg/m) 3 ) At a flow rate of 856322m 3 Delivering the air into the middle part of a desulfurizing tower, and in the desulfurizing tower, an axial flow type oxidation fan is used for leading the air to flow 7804m through a gas distribution pipe 3 /h (air flow rate m) 3 /h=856322m 3 /h*1519mg/m 3 *10 -6 *0.25/(0.18*0.2315kg/m 3 ) Feeding into the lower part of desulfurizing tower, at pulse pump flow rate of 3500m 3 At the temperature of/h, carrying out pulse stirring reaction to obtain carbide slag desulfurization slurryDischarging the liquid and the sulfur-removing flue gas;
when the water content of the dehydrated gypsum is more than or equal to 15 percent, limestone slurry of 1.8t/h (the density is 1200 kg/m) is added into a desulfurizing tower 3 ) Until the water content of the dehydrated gypsum is less than 15%;
(4) Circulating the carbide slag desulfurization slurry obtained in the step (3) to the top of a desulfurization tower (the sum of the flow of the carbide slag desulfurization slurry circulation, the flow of fresh carbide slag slurry and the flow of limestone slurry, and the liquid-gas ratio L/m of sulfur-containing flue gas) 3 18) and feeding the gypsum slurry into a calcium sulfate crystallization tank at a flow rate of 6t/h (8.2 t/h when limestone slurry is added), crystallizing at a pH value of 4.5, and dehydrating the gypsum slurry (solid content of 34.8%) to a water content of 11.9% by a disc dehydrator to obtain dehydrated gypsum.
In the step (4), wastewater generated by crystallization and dehydration is subjected to electric flocculation neutralization treatment, which comprises the following steps: the waste water produced by crystallization and dehydration is firstly adjusted to pH value of 7.0 by using waste alkali liquor of a power plant, then electric flocculation is carried out, and after the sludge and the waste water are separated, the sludge is sent into a disc type dehydrator again for dehydration.
Through detection, the concentration of sulfur dioxide in the desulfurization flue gas discharged in the step (3) is 11mg/m 3 The desulfurization rate was 99.3%.
Comparative example 1
(1) Filtering 10t carbide slag sequentially by a filter screen, a rotary screen and a vibrating screen to remove coarse slag, and then sending the obtained fine slag into an iron remover to remove iron under the magnetic field strength of 1800kA/m to obtain 9.9t carbide screening slag;
(2) Feeding 9.9t of calcium carbide screening slag obtained in the step (1) into a calcium carbide slag slurry pool, adding 24t of water, and stirring and slurrying for 0.5h at the rotating speed of 300rpm to obtain calcium carbide slag slurry;
(3) The carbide slag slurry obtained in the step (2) is mixed with a flow rate of 11t/h (the flow rate of the carbide slag slurry t/h=4.9 x 1137322m 3 /h*1985mg/m 3 *10 -9 The pH value in the slurry of the absorption tower is controlled to be 5.0, and the slurry is sent to the top of a desulfurizing tower, and sulfur-containing flue gas (the concentration is 1985 mg/m) 3 ) At a flow rate of 1137322m 3 Delivering the air into the middle part of a desulfurizing tower, and in the desulfurizing tower, an axial flow type oxidation fan delivers the air with the flow rate of 12190m through a gas distribution pipe 3 /h (air flow rate m) 3 /h=1137322m 3 /h*1985mg/m 3 *10 -6 *0.25/(0.2*0.2315kg/m 3 ) Feeding into the lower part of desulfurizing tower at pulse pump flow rate of 4000m 3 And (3) at the step (h), carrying out pulse stirring reaction to obtain carbide slag desulfurization slurry and discharging desulfurization flue gas;
(4) Circulating the carbide slag desulfurization slurry obtained in the step (3) to the top of a desulfurization tower (the sum of the flow of the carbide slag desulfurization slurry and the flow of the fresh carbide slag slurry, and the liquid-gas ratio L/m of sulfur-containing flue gas) 3 20) and partially feeding the gypsum slurry into a calcium sulfate crystallization pond at a flow rate of 12.1t/h, crystallizing at a pH value of 4.9, and dehydrating the gypsum slurry (solid content of 35.2%) to a water content of 11.8% by using a disc dehydrator to obtain dehydrated gypsum.
In the step (4), wastewater generated by crystallization and dehydration is subjected to electric flocculation neutralization treatment, which comprises the following steps: the waste water produced by crystallization and dehydration is firstly adjusted to pH value of 7.0 by using waste alkali liquor of a power plant, then electric flocculation is carried out, and after the sludge and the waste water are separated, the sludge is sent into a disc type dehydrator again for dehydration.
Through detection, the concentration of sulfur dioxide in the desulfurization flue gas discharged in the step (3) is 54mg/m 3 The desulfurization rate is 97.3%, which shows that the pH value has a larger influence on the carbide slag desulfurization effect.
Claims (10)
1. The utility model provides a coal fired power plant flue gas carbide slag wet flue gas desulfurization system which characterized in that includes: the device comprises a filter screen (1), a rotary screen (2), a vibrating screen (3), an iron remover (4), a carbide slag slurry pool (5), a desulfurizing tower (6), a calcium sulfate crystallization pool (7) and a disc dehydrator (8); fine slag of the carbide slag raw material screened by the filter screen (1) is sent to a rotary screen (2); fine slag in the rotary screen (2) is sent to a vibrating screen (3), fine slag screened by the vibrating screen (3) is sent to an iron remover (4), and calcium carbide screening slag removed by iron in the iron remover (4) is sent to a calcium carbide slag slurry pool (5); the carbide slag slurry pool (5) is connected with the top of the desulfurizing tower (6); the sulfur-containing flue gas is sent into the middle part of the desulfurizing tower (6) and is discharged from the top, and the air is sent into the lower part of the desulfurizing tower (6) and is discharged from the top; the carbide slag desulfurization slurry in the desulfurization tower (6) is circulated to the top of the desulfurization tower (6), or the carbide slag desulfurization slurry discharged from the lower part of the desulfurization tower (6) is sent into a calcium sulfate crystallization pond (7) for crystallization, and the crystallized slurry enters a disc type dehydrator (8) for dehydration.
2. The wet desulfurization system for flue gas carbide slag of a coal-fired power plant according to claim 1, wherein: the wastewater generated by the calcium sulfate crystallization pond (7) and the disc type dehydrator (8) is sent into an electric flocculation treatment pond (9) for treatment; the limestone slurry tank (10) is connected with the carbide slag slurry tank (5) in parallel and is connected with the top of the desulfurizing tower (6); the carbide slag slurry tank (5) and the limestone slurry tank (10) are respectively provided with a stirring slurry device; slurry circulating pumps are arranged between the carbide slag slurry tank (5) and the limestone slurry tank (10) and the desulfurizing tower (6) and between the lower part and the top of the desulfurizing tower (6), and a flow rate valve is arranged on an output pipeline.
3. The wet desulfurization system for flue gas carbide slag of a coal-fired power plant according to claim 1 or 2, wherein: the pore diameter of the filter screen (1) is 180-240 mu m; the aperture of the filter screen of the drum screen (2) is 70-100 mu m; the pore diameter of the filter screen of the vibrating screen (3) is 50-65 mu m.
4. A wet desulfurization system for flue gas carbide slag of a coal-fired power plant according to any one of claims 1 to 3, characterized in that: the height-diameter ratio of the desulfurizing tower (6) is 3-5:1; a slurry inlet pipe (601) is arranged at one side of the top of the desulfurizing tower (6), and the upper end of the slurry inlet pipe (601) is butted with the lower ends of the output pipelines of the carbide slag slurry tank (5) and the limestone slurry tank (10); a flue gas inlet pipe (602) is arranged in the middle of the desulfurizing tower (6); the lower part of the desulfurizing tower (6) is provided with a desulfurizing slurry output pipe (603) and is respectively connected with a slurry inlet pipe (601) and a calcium sulfate crystallization pond (7); a desulfurization flue gas discharge pipe (604) is arranged in the middle of the top end of the desulfurization tower (6); a display panel (605) is arranged in the middle of the desulfurizing tower (6); the display panel (605) is electrically connected with a temperature probe and a pH value probe in the desulfurizing tower (6); an axial-flow oxidation fan (606) is arranged at the lower part of the desulfurizing tower (6), and the part extending into the desulfurizing tower (6) is a gas distribution pipe; the bottom of the inner cavity of the desulfurizing tower (6) is provided with a pulse pump (607).
5. The wet desulfurization system for flue gas carbide slag of a coal-fired power plant according to claim 4, wherein: the slurry inlet pipe (601) is provided with a downward spray header (60101) at the tail end bending part positioned in the middle of the top of the inner cavity of the desulfurizing tower (6); a beam-waist-shaped flue gas demister (608) with wide upper and lower ends and narrow middle is fixedly arranged in the inner cavity of the desulfurizing tower (6) below the spray header (60101); the middle part of flue gas defroster (608) is the through-hole, and through-hole department is equipped with spiral-flow type buckled plate (60801) that annular distributes, and the spiral is equipped with scale removal guiding gutter (60802) on flue gas defroster (608) upper end inner chamber lateral wall.
6. A wet desulfurization method for flue gas carbide slag of a coal-fired power plant based on the desulfurization system as claimed in any one of claims 1 to 5, comprising the following steps:
(1) The calcium carbide slag is filtered by a filter screen, a rotary screen and a vibrating screen in sequence to remove coarse slag, and the obtained fine slag is sent to an iron remover to remove iron so as to obtain calcium carbide screening slag;
(2) Feeding the calcium carbide screening slag obtained in the step (1) into a calcium carbide slag slurry pond, adding water, stirring and slurrying to obtain calcium carbide slag slurry;
(3) Sending the carbide slag slurry obtained in the step (2) to the top of a desulfurization tower, sending sulfur-containing flue gas to the middle of the desulfurization tower, sending air to the lower part of the desulfurization tower, and carrying out pulse stirring reaction in the desulfurization tower to obtain carbide slag desulfurization slurry and discharging desulfurization flue gas;
(4) And (3) recycling the carbide slag desulfurization slurry obtained in the step (3) to the top of the desulfurization tower, or partially feeding the carbide slag desulfurization slurry into a calcium sulfate crystallization pond, crystallizing, and dehydrating to obtain dehydrated gypsum.
7. The coal-fired power plant of claim 6The wet desulfurization method for the flue gas carbide slag of the factory is characterized by comprising the following steps of: in the step (1), the main components and mass fractions of the carbide slag are as follows: caO 80-95%, siO 2 2～8%，Fe 2 O 3 0.5 to 1.5 percent, and the total mass fraction is less than or equal to 100 percent; the magnetic field strength of the iron removal is 1500-2200 kA/m.
8. The wet desulfurization method for the flue gas carbide slag of the coal-fired power plant according to claim 6 or 7, wherein the method comprises the following steps: in the step (2), the mass ratio of water to the calcium carbide screening slag is 2.2-3.6:1; the rotational speed of stirring and slurrying is 200-400 rpm, and the time is 1-3 h.
9. The wet desulfurization method for the flue gas carbide slag of the coal-fired power plant according to one of claims 6 to 8, which is characterized in that: in step (3), the carbide slag slurry flow t/h=e is the sulfur-containing flue gas flow m 3 Concentration of sulfur dioxide in sulfur-containing flue gas mg/m 3 *10 -9 Wherein, E=3.2-4.7, and the flow rate of the carbide slag slurry is regulated within the range of E value so that the pH value in the slurry of the absorption tower is 4.2-4.8; the flow rate of the sulfur-containing flue gas is 5 ten thousand to 200 ten thousand m 3 /h; the concentration of sulfur dioxide in the sulfur-containing flue gas is 500-5000 mg/m 3 The method comprises the steps of carrying out a first treatment on the surface of the The flow of the pulse pump for the pulse stirring reaction is 2000-5000 m 3 /h; the flow rate m of the air 3 H=sulfur-containing flue gas flow m 3 Concentration of sulfur dioxide in sulfur-containing flue gas mg/m 3 *10 -6 *0.25/(k*0.2315kg/m 3 ) Wherein k=0.18 to 0.28; when the concentration of sulfur dioxide in the desulfurization flue gas is more than or equal to 60mg/m 3 Or when the water content of the dehydrated gypsum is more than or equal to 15%, limestone slurry is added into a desulfurization tower until the concentration of sulfur dioxide in the desulfurization flue gas is less than 30mg/m 3 Or the water content of the dehydrated gypsum is less than 15%; the flow rate of the limestone slurry is 0.1-0.4 times of the flow rate of the carbide slag slurry; the density of the limestone slurry is 1180-1250 kg/m 3 。
10. The wet desulfurization method for the carbide slag in the flue gas of the coal-fired power plant according to any one of claims 6 to 9, which is characterized in that: in the step (4), the sum of the circulating flow of the carbide slag desulfurization slurry, the fresh carbide slag slurry flow and the limestone slurry flow and the liquid-gas ratio L/m of the sulfur-containing flue gas 3 Not less than 8; the flow rate of the carbide slag desulfurization slurry fed into the calcium sulfate crystallization pond is 1.01 to 1.20 times of the sum of the flow rate of the fresh carbide slag slurry and the flow rate of the limestone slurry; the pH value of the crystal is 4.2-4.8; the solid content of the gypsum slurry before dehydration is 25-40%, and the water content of the dehydrated gypsum is 5-14%; neutralizing wastewater generated by crystallization and dehydration by adopting electric flocculation; the electric flocculation neutralization treatment specifically comprises the following steps: firstly, waste water produced by crystallization and dehydration is adjusted to pH value of 6.5-7.5 by waste alkali liquor, then electric flocculation is carried out, and after sludge and waste water are separated, the sludge enters a disc type dehydrator again for dehydration.
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| CN117244375B (en) * | 2023-10-10 | 2024-03-08 | 南京凯摩昱斯科技有限公司 | Method for absorbing carbon dioxide in industrial tail gas by using carbide slag |
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