CN116139674A - Dry method and semi-dry method desulfurization ash central symmetry jet oxidation tower and operation treatment method thereof - Google Patents

Dry method and semi-dry method desulfurization ash central symmetry jet oxidation tower and operation treatment method thereof Download PDF

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CN116139674A
CN116139674A CN202111391305.6A CN202111391305A CN116139674A CN 116139674 A CN116139674 A CN 116139674A CN 202111391305 A CN202111391305 A CN 202111391305A CN 116139674 A CN116139674 A CN 116139674A
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slurry
jet
tower
pipe
pipeline
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赵岩
邵春岩
王坚
陈刚
陈明
曾乐
张广鑫
裴江涛
赵阳
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Shenyang Academy Environmental Sciences
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/73—After-treatment of removed components
    • 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
    • B01D53/346—Controlling the process
    • 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
    • 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
    • B01D53/504—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 device
    • 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
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/80—Semi-solid phase processes, i.e. by using slurries
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/81—Solid phase processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/40—Alkaline earth metal or magnesium compounds
    • B01D2251/404—Alkaline earth metal or magnesium compounds of calcium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/60—Inorganic bases or salts
    • B01D2251/608—Sulfates
    • 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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Abstract

The invention relates to a dry method and semi-dry method desulfurization ash central symmetry jet oxidation tower and an operation treatment method thereof, which mainly solve the problem that the existing dry method and semi-dry method desulfurization ash cannot be comprehensively utilized on a large scale, realize the recycling of waste sulfuric acid, achieve the aim of treating waste by waste, and create remarkable economic and environmental benefits. The method is characterized in that: the whole device mainly comprises a jet aeration tower and SO 2 Absorption tower, first jet aerator, second jet aeratorThe device comprises a first slurry pump, a second slurry pump, a first blower, a second blower, an acid liquid pump and the like; decomposing the conventional one-step oxidation process into multiple steps, precisely controlling the pH of slurry in each step, and simultaneously combining SO 2 Reabsorption measures not only avoid CaSO 3 Large scale decomposition and SO 2 Secondary pollution and ensure sufficient amount of CaSO 3 In a liquid phase reaction system, the problem of slow oxidation rate caused by high alkalinity of the dry method and the semi-dry method desulfurization ash is finally solved, and the clean and efficient modification is creatively realized.

Description

Dry method and semi-dry method desulfurization ash central symmetry jet oxidation tower and operation treatment method thereof
Technical Field
The invention belongs to the technical field of resources and environment, relates to stabilization modification and resource utilization of dry and semi-dry desulfurization ash, in particular to a central symmetry jet oxidation tower of dry and semi-dry desulfurization ash, and also provides an operation treatment method of the device.
Background
In recent years, because of the high importance of China on ecological environment protection and SO 2 The emission requirements are becoming strict, and the flue gas desulfurization process is widely popularized and applied in industries such as coal-fired power plants, steel sintering, industrial boilers, petrochemical industry and the like, wherein the dry-method and semi-dry-method desulfurization process represented by CFB, LIFAC, NID, SDA, CDSI has the advantages of small occupied area, low investment, low operation cost, low energy consumption, no wastewater and waste acid emission and the like, and has become the trend of the future development of the flue gas desulfurization technology.
The dry and semi-dry desulfurizing process features that powdered or granular calcium-base absorbent is used to remove SO from fume 2 The desulfurization product is dry powder and mainly comprises CaSO 3 ·1/2H 2 O、CaCO 3 、CaSO 4 ·2H 2 O and small amounts of unreacted Ca (OH) 2 Etc. Compared with the wet desulfurization process, the desulfurization ash produced by the dry desulfurization process and the semi-dry desulfurization process has the characteristics of much more complex components, high sulfur, high calcium and high alkalinity, in particular CaSO 3 The components with poor chemical stability cause the dry method and the semi-dry method desulfurization ash to show unusual physicochemical properties. Because the research on the properties, reaction characteristics and action mechanisms of the solid waste is not enough and deep, at present, people have a plurality of judicious attitudes on comprehensive utilization of the solid waste, and no effective utilization way is formed, so that the dry and semi-dry desulfurization ash is accumulated in a large amount or is simply buried, a large amount of precious land resources are occupied, the burden of enterprises is increased, and the further popularization and application of the dry and semi-dry desulfurization process are restricted. In addition, due to CaSO 3 Instability of (C) is extremely prone to SO after long-term stacking 2 Is a potential threat to the environment; meanwhile, as the particle size of the dry method and the semi-dry method desulfurization ash is smaller, the mass is lighter, and once the desulfurization ash is blown by wind, dust pollution can be generated.
For the comprehensive utilization of dry and semi-dry desulfurization ash, the related work at home and abroad at present does not form a complete system, the obtained results belong to research properties, any large-scale industrialized application technology is not formed yet, and the reason is mainly that the method comprises the following four aspects:
(1) The chemical composition of the desulphurized ash is very complex. The phase composition of the common dry method and semi-dry method desulfurization ash comprises CaSO 4 、CaSO 3 、CaCO 3 、Ca(OH) 2 、CaO、MgCO 3 The components are complex and various in chemical properties, so that the comprehensive utilization is more limited and more difficult.
(2) The content of each component of the desulfurized fly ash fluctuates greatly. Due to the differences of operation, running and management levels of different enterprise equipment, the differences of different raw material types and batching schemes, the differences of desulfurization efficiency of different desulfurization processes and the differences of coal-fired components of different batches, the contents of components of desulfurization ash generated by different desulfurization equipment and different time periods of the same equipment can be greatly fluctuated. Such fluctuations bring about frequent changes in the overall chemical properties, which make its comprehensive utilization very difficult.
(3) The chemical nature of the various components in the desulphurized ash is not stable. CaSO in desulfurized fly ash 3 、Ca(OH) 2 And CaO, are unstable in chemical properties and change with environmental and time changes. CaSO (Caso-like conductor) 3 In an acidic environment or under the high temperature condition of neutral or reducing atmosphere, the SO is decomposed easily 2 And released again to cause secondary pollution of the environment, and simultaneously CaSO 3 Will oxidize to CaSO in air 4 Resulting in instability of the properties of the desulfurized ash material over long periods of use. CaO absorbs water very easily to generate Ca (OH) 2 Causes volume non-uniform expansion, ca (OH) 2 Reabsorption of CO from air 2 To generate CaCO 3 . These instabilities create a major obstacle to the comprehensive utilization of the desulfurization ash.
(4) CaSO in desulfurized fly ash 3 Is very high in CaSO 3 The effect and mechanism of the action of (a) are not clear. CaSO in dry and semi-dry desulfurization ash 3 Can be up to 50% or more, and CaSO 3 The influence on the overall mechanical properties and stability of the material is yet to be further studied and confirmed. For example, when the desulfurized fly ash is used as a cement retarder, caSO 3 The retarding effect of (2) and the influence on the cement mechanical property are still in great dispute.
In summary, under the new background of the huge promotion of the construction of the 'no-waste city' and 'double-carbon' targets in China, the harmless and deep recycling of the desulfurization ash by the dry method and the semi-dry method are realized by large-scale scientific treatment, so that the method is not only the technical problems to be solved in the industries of coal-fired power plants, steel sintering, industrial boilers, petrochemical industry and the like in China, but also the promotion of ecological civilization construction in China, the promotion of high-quality development and the realization of the necessary requirements of comprehensive resource conservation and recycling are promoted.
Based on basic chemical principles of acid-base neutralization and oxidation reduction, the dry-method and semi-dry-method desulfurization ash is subjected to forced oxidation modification in a sulfuric acid environment, so that the limit can be solved at one timeFour aspects of problems of large-scale comprehensive utilization of the solid waste are that: caCO in desulfurized fly ash under the action of acid-base neutralization reaction 3 、Ca(OH) 2 Alkaline components such as CaO and the like are all rapidly converted into CaSO 4 The method comprises the steps of carrying out a first treatment on the surface of the Under the action of oxidation reaction, caSO with poor stability 3 Will also be converted into CaSO 4 . Thus, the dry method and semi-dry method desulfurization ash with complex and various original components and unstable contents and chemical properties of various components is converted into a stable CaSO 4 As a major component, the chemical properties of the solid waste are similar to those of wet desulfurization gypsum. Because the technical problems of all links in the comprehensive utilization of the wet desulfurization gypsum are basically solved, the modified dry desulfurization ash and the modified semi-dry desulfurization ash can be comprehensively utilized on a large scale according to various technical routes of the wet desulfurization gypsum, thereby thoroughly solving the increasingly urgent treatment problem of the bulk solid waste. Meanwhile, the recycling of the waste sulfuric acid is realized.
However, due to SO 3 2- Will be in excess of H + Bind to form pollutant SO 2 The pH of the reaction solution must not be too low; at the same time, the dissolution process of the desulfurization ash can lead the pH value of the solution to be rapidly increased due to the strong alkalinity of the desulfurization ash, while the CaSO 3 The solubility of (c) is low and further decreases with increasing pH, so that the oxidation rate decreases considerably, and the solid-to-liquid ratio of the dissolution process, i.e. the pH of the solution, cannot be too high. In conclusion, the high-efficiency oxidation of the dry-method and semi-dry-method desulfurization ash is realized in a one-step method and conventional slurry mode, and meanwhile, SO is not contained 2 Release is very difficult and there is a need to develop innovative oxidative modification devices and methods that adapt to the characteristics of the desulfurization ash.
Disclosure of Invention
In order to solve the technical problems in the background technology, the invention provides the dry method and semi-dry method desulfurization ash central symmetry jet oxidation tower which has the advantages of low cost, stable operation, convenient construction and flexible operation and the operation treatment method thereof.
In order to achieve the purpose, the invention provides a dry method and semi-dry method desulfurization ash central symmetry jet oxidation tower, which has the technical key points that:
the whole device consists of a jet aeration tower and SO 2 The device comprises an absorption tower, a first jet aerator (the number is 2), a second jet aerator (the number is 2), a first slurry pump, a second slurry pump, a first blower, a second blower, an acid pump, a first desulfurization ash feeding pipe, a second desulfurization ash feeding pipe, a first flexible joint, a second flexible joint, a first oxidation air pipe (the number is 2), a second oxidation air pipe (the number is 2), a first exhaust pipe, a second exhaust pipe, a first liquid level meter flange, a second liquid level meter flange, a first pressure meter flange, a second pressure meter flange, a first high-level slurry discharge pipe, a second high-level slurry discharge pipe, a first pH probe flange, a second pH probe flange, a first thermometer flange, a second thermometer flange, a first densimeter flange, a second densimeter flange, a reabsorption slurry merging pipe, a first low-level slurry discharge pipe (the number is 2), a second low-level slurry discharge pipe (the number is 2), an acid liquid feeding pipe, a first manhole and a second manhole.
The number of the first jet aerator and the second jet aerator is 2, and the first jet aerator and the second jet aerator are respectively arranged on the jet aeration tower and the SO 2 The inner low position of the absorption tower takes the center of the bottom surface as a symmetrical point and is arranged in a central symmetry way; the first desulfurization ash feeding pipe, the first flexible joint, the first oxidation air pipe (the number is 2), the first exhaust pipe, the first liquid level meter flange and the first pressure meter flange are arranged at the top of the jet aeration tower; the second desulfurized ash feed pipe, the second flexible joint, the second oxidation air pipe (the number is 2), the second exhaust pipe, the second liquid level meter flange and the second pressure meter flange are arranged on the SO 2 The top of the absorption tower; the first and the second high-order slurry discharge pipes are respectively arranged on the jet aeration tower and the SO 2 An upper side wall of the absorption tower; the first pH probe flange and the second pH probe flange are respectively and equidistantly arranged on the jet aeration tower and the SO from top to bottom 2 The side wall of the absorption tower; the first thermometer flange and the second thermometer flange are respectively arranged on the jet aeration tower and the SO 2 The side wall of the middle part of the absorption tower; the first densimeter flange and the second densimeter flange are respectively arranged on the jet aeration tower and the SO 2 The side wall of the middle lower part of the absorption tower; the reabsorption slurry merging pipe is arranged on the side wall of the lower part of the jet aeration tower; first, the firstTwo low-level slurry discharge pipes (the number is 2) are respectively arranged on the jet aeration tower and the SO 2 The bottom of the absorption tower; the acid liquor feeding pipe is arranged at the bottom of the jet aeration tower; the first manhole and the second manhole are respectively arranged on the jet aeration tower and the SO 2 The lower side wall of the absorption tower.
The inlet of the first slurry pump is connected with a first high-position slurry discharge pipe, a first low-position slurry discharge pipe (the number is 2) and a clear water pipe (not in the scope of the patent), and the outlet of the first slurry pump is connected with a slurry inlet of a first jet aerator (the number is 2) and a gypsum dehydration unit (not in the scope of the patent) through a three-way pipeline; the inlet of the second slurry pump is connected with a second high-position slurry discharge pipe and a second low-position slurry discharge pipe (the number is 2) and a clear water pipe (which do not belong to the scope of the patent) through a four-way pipeline, and the outlet is connected with the slurry inlet of the second jet aerator (the number is 2) and a reabsorption slurry merging pipe through a three-way pipeline; the outlets of the first blower and the second blower are respectively connected with the air inlets of the first jet aerator and the second jet aerator (the number of which is 2) through the first oxidation air pipe and the second oxidation air pipe (the number of which is 2); the inlet of the second air blower is connected with the first exhaust pipe; the outlet of the acid liquor pump is connected with an acid liquor feeding pipe; the first flexible joint and the second flexible joint are respectively connected with the first desulfurization ash feeding pipe and the second desulfurization ash feeding pipe.
The jet aeration tower and SO 2 The absorption towers are vertical cylinders, the height-diameter ratio is 2-10, and guide plates are arranged in the inner wall areas opposite to the first jet aerator nozzle and the second jet aerator nozzle.
The number of the first jet aerator and the second jet aerator is 2, and the single nozzle and the central symmetrical arrangement mode are adopted.
The first blower and the second blower are respectively Roots blower or centrifugal blower.
The acid liquid pump adopts a metering pump.
The first flexible joint and the second flexible joint are both made of rubber corrugated pipes.
The number of the flanges of the first pH probe and the second pH probe is 3-10, and the flanges are respectively arranged along the jet aeration tower and the SO 2 The absorption towers are arranged at equal intervals from top to bottom in the height direction.
The second exhaust pipe is provided with SO 2 And an on-line monitoring device.
The invention also provides an operation treatment method of the dry method and semi-dry method desulfurization ash central symmetry jet oxidation tower, which is characterized in that: the method comprises the following eleven steps:
step one: and (5) analyzing and testing raw materials. Analyzing and testing the components of the dry and semi-dry desulfurization ash to determine CaSO therein 3 And the content of various strongly basic compounds.
Step two: alkali liquor preparation. Only the inlet clear water pipeline and the outlet aerator pipeline of the second slurry pump are opened, and the second slurry pump is utilized to feed SO 2 Injecting clear water into the absorption tower, opening an inlet high-level slurry pipeline of the second slurry pump when the liquid level is higher than that of the second high-level slurry discharge pipe, and closing the inlet clear water pipeline; feeding the desulfurized fly ash into the SO through the second flexible joint and the second desulfurized fly ash feed pipe by using a pipe chain or a screw conveyor 2 An absorption tower; the desulfurized ash just entering the tower is immediately sucked into a second slurry pump and is sprayed out by a nozzle of a second jet aerator, the rapid and sufficient mixing and dissolving process with the clean water are completed, and finally the pH value is formed>10; stopping feeding the desulfurized fly ash, opening an inlet low-level slurry pipeline of the second slurry pump, and closing an inlet high-level slurry pipeline.
Step three: acid liquor preparation. Waste sulfuric acid with low heavy metal and organic pollutant content and mass fraction of 1% -95% is gradually injected into the jet aeration tower by using the acid pump; only opening an inlet clear water pipeline and an outlet aerator pipeline of the first slurry pump, and injecting clear water into the jet aeration tower by using the first slurry pump; stopping feeding the waste sulfuric acid and the clean water after the pH value of the solution in the tower is stabilized between 2.2 and 4.2 and the liquid level is higher than that of the first high-level slurry discharge pipe; and opening an inlet high-level slurry pipeline of the first slurry pump, and closing an inlet clear water pipeline.
Step four: and (5) desulfurizing and acidifying. Feeding the desulfurization ash into a jet aeration tower through the first flexible joint and a first desulfurization ash feeding pipe by utilizing a pipe chain or a screw conveyor; the desulfurized ash just entering the tower is immediately sucked into a first slurry pump and is sprayed out by a nozzle of a first jet aerator, so that the rapid and sufficient mixing, dissolving and reacting processes with the acid liquor are completed; and stopping feeding the desulfurization ash when the pH value of the solution is raised to 3.1-6.2 and is kept stable.
Step five: and (5) forced oxidation. Opening an inlet low-level slurry pipeline of the first slurry pump, and closing an inlet high-level slurry pipeline; the first jet aerator sucks air through a first oxidation air pipe and sprays the air and the solution in the fourth step through a nozzle to finish multiphase mixing and efficient mass transfer processes, and at the moment, HSO in the solution is discharged 3 - Will be O 2 Oxidation to SO 4 2- Releasing H + Thereby lowering the pH of the solution; when the suction provided by the first jet aerator is insufficient, the first air blower is started to provide enough power for the air.
Step six: and (5) secondary acidification. When the pH value of the solution in the fifth step tends to be stable, starting the acid liquid pump, and gradually adding the waste sulfuric acid in the fourth step into the jet aeration tower; immediately sucking the waste sulfuric acid which just enters the tower into a first slurry pump, spraying the waste sulfuric acid out of the tower through a nozzle of a first jet aerator, completing the rapid and sufficient mixing and reaction process with the solution, reducing the pH value of the solution to be between 2.2 and 4.2 again, and then closing an acid liquid pump; and opening an inlet high-level slurry pipeline of the first slurry pump, and closing an inlet low-level slurry pipeline.
Step seven: a multi-step cycle. Repeating the steps four to six continuously to ensure that the solution in the step six gradually has solid-phase CaSO 4 Separating out and finally forming the slurry with the solid content of 6% -30%.
Step eight: and partially discharging slurry. When the slurry liquid level or density in the seventh step reaches a certain value, opening an inlet low-level slurry pipeline and an outlet dehydration unit pipeline of the first slurry pump, closing an inlet high-level slurry pipeline and an outlet aerator pipeline, discharging a part of slurry by using the first slurry pump, and delivering the slurry to a dehydration unit to produce gypsum products; in the pulp discharging process, the liquid level in the jet aeration tower is kept higher than that of the first high-level pulp discharging pipe; and after the slurry discharge is completed, opening an inlet high-level slurry pipeline and an outlet aerator pipeline of the first slurry pump, and closing an inlet low-level slurry pipeline and an outlet dehydration unit pipeline.
Step nine: SO (SO) 2 And (5) re-absorption. In multi-step cyclic oxidation, especially secondary acidification, there may be local pH of the slurry that is too low, resulting in incompletely oxidized SO 3 2- With excess H + Binding to release SO 2 In the case of (a), this part of SO 2 Discharging through said first exhaust pipe; the second jet aerator uses a second oxidation air pipe to oxidize the part of SO 2 Sucking and spraying the mixed solution and alkaline slurry from the second step through a nozzle to realize multiphase mixing and efficient mass transfer to complete SO 2 A reabsorption process; when the suction provided by the second jet aerator is insufficient, the second blower is started to entrain SO 2 Providing sufficient power for the airflow.
Step ten: and (5) merging the reabsorption slurry. With the alkaline slurry of the second step continuously absorbing SO 2 The pH value of the water is gradually reduced; when the pressure is reduced to below 8.5, and after the secondary acidification in the step six is completed, opening an outlet reabsorption slurry merging pipeline of the second slurry pump, closing an outlet aerator pipeline, and sending alkaline slurry into a jet aeration tower by using the second slurry pump; and opening an inlet low-level slurry pipeline of the first slurry pump, closing an inlet high-level slurry pipeline, and performing merging oxidation treatment.
Step eleven: and finishing the modification. And continuously repeating the second step, the fourth step and the tenth step, and finally finishing the centrosymmetric jet oxidation of all the dry-method and semi-dry-method desulfurized ash.
Compared with the prior art, the invention has the following beneficial effects:
(1) Based on the optimal solid-liquid ratio, the pH value of the acidified slurry in the whole multiphase jet oxidation process is always controlled to be 2.2-6.2, so that the CaSO in the desulfurized fly ash can be avoided to the maximum extent 3 Decompose to release SO 2 And can ensure enough CaSO 3 In a liquid phase reaction system, thereby remarkably improving the reaction rate of the whole oxidation process.
(2) The conventional one-step oxidation process is decomposed into multiple steps, and the problem of slow oxidation rate caused by the high alkalinity of the dry method and the semi-dry method desulfurization ash is solved by precisely controlling the solid-to-liquid ratio and the slurry pH of each step of oxidation process, so that the high-efficiency oxidation of the high alkalinity desulfurization ash is creatively realized.
(3) CaSO in desulfurized ash by adopting novel jet aeration technology 3 The single-nozzle jet aerator arranged in a central symmetry manner can generate resultant force to form strong slurry vortex, has strong mixing and stirring effects, has higher oxygenation capacity, oxygen utilization rate and oxygen power transfer efficiency, has the advantages of simple structure, no moving parts, reliable operation, flexible operation, convenient adjustment, difficult blockage, easy maintenance and management, low operation cost and the like, and can obviously improve the reaction rate of the forced oxidation process.
(4) The method can realize the resource utilization of the dry method and the semi-dry method desulfurization ash and the waste sulfuric acid at the same time, thereby achieving the purposes of treating waste with waste and cooperatively recycling, and obtaining better economic and environmental benefits.
(5) With a double-column reactor type, the second reaction column is used for SO 2 And reabsorption is carried out, so that the risk of secondary pollution is further reduced.
(6) The flexible joint can effectively relieve harmful vibration transferred between the desulfurization ash conveying equipment and the reaction tower while ensuring the tightness of the system, and improves the safety and stability of the operation of the system.
Drawings
FIG. 1 is a schematic view of the apparatus of the present invention;
fig. 2 is a cross-sectional view taken along A-A of fig. 1.
FIG. 3 shows a semi-dry desulfurization ash and 80% concentrated H in a certain iron and steel plant 2 SO 4 The reagent is used as raw material, the pH regulation acidification and forced oxidation laboratory test is carried out according to the step method of the invention, and when the solid content of the final slurry reaches 10%, the slurry is derived from CaSO 3 S balance diagram of (2).
The reference numerals in fig. 1 are as follows: 1-jet aeration tower, 2-SO 2 Absorption tower, 3-first jet aerator, 4-second jet aeratorJet aerator, 5-first slurry pump, 6-second slurry pump, 7-first blower, 8-second blower, 9-acid pump, 10-first desulfurization ash feed pipe, 11-second desulfurization ash feed pipe, 12-first flexible joint, 13-second flexible joint, 14-first oxidation air pipe, 15-second oxidation air pipe, 16-first exhaust pipe, 17-second exhaust pipe, 18-first liquid level meter flange, 19-second liquid level meter flange, 20-first pressure meter flange, 21-second pressure meter flange, 22-first high-level slurry discharge pipe, 23-second high-level slurry discharge pipe, 24-first pH probe flange, 25-second pH probe flange, 26-first thermometer flange, 27-second thermometer flange, 28-first densimeter flange, 29-second densimeter flange, 30-reabsorption slurry merging pipe, 31-first low-level slurry discharge pipe, 32-second low-level slurry discharge pipe, 33-acid liquid manhole, 34-first manhole, 35-second feed pipe.
Detailed Description
The invention will be further described with reference to the drawings and the specific examples.
As shown in figures 1-2, the invention relates to a dry method and semi-dry method desulfurization ash central symmetry jet oxidation tower, which consists of a jet aeration tower 1 and SO 2 The absorption tower 2, the first jet aerator 3, the second jet aerator 4, the first slurry pump 5, the second slurry pump 6, the first blower 7, the second blower 8, the acid liquid pump 9, the first desulfurization ash feed pipe 10, the second desulfurization ash feed pipe 11, the first flexible joint 12, the second flexible joint 13, the first oxidation air pipe 14, the second oxidation air pipe 15, the first exhaust pipe 16, the second exhaust pipe 17, the first liquid level meter flange 18, the second liquid level meter flange 19, the first pressure meter flange 20, the second pressure meter flange 21, the first high-level slurry discharge pipe 22, the second high-level slurry discharge pipe 23, the first pH probe flange 24, the second pH probe flange 25, the first thermometer flange 26, the second thermometer flange 27, the first densimeter flange 28, the second densimeter flange 29, the reabsorption slurry merging pipe 30, the first low-level slurry discharge pipe 31, the second low-level slurry 32, the feed pipe 33, the first man hole 34 and the second man hole 35.
First 3 and second shotsThe number of the flow aerators 4 is 2, and the flow aerators are respectively arranged in the jet aeration tower 1 and the SO 2 The absorption tower 2 is arranged at the lower position inside and is in central symmetry by taking the center of the bottom surface as a symmetry point; the first desulfurized ash feed pipe 10, the first flexible joint 12, the first oxidation air pipes 14 (the number is 2), the first exhaust pipe 16, the first liquid level meter flange 18 and the first pressure meter flange 20 are arranged at the top of the jet aeration tower 1; the second desulfurized fly ash feed pipe 11, the second flexible joint 13, the second oxidation air pipe 15 (the number is 2), the second exhaust pipe 17, the second liquid level meter flange 19 and the second pressure meter flange 21 are arranged on the SO 2 The top of the absorption tower 2; a first 22 and a second high-order slurry discharge pipe 23 are respectively arranged on the jet aeration tower 1 and the SO 2 An upper side wall of the absorption column 2; the first 24 and the second pH probe flange 25 are respectively and equidistantly arranged on the jet aeration tower 1 and the SO from top to bottom 2 The side wall of the absorption tower 2; a first thermometer flange 26 and a second thermometer flange 27 are respectively arranged on the jet aeration tower 1 and the SO 2 The middle side wall of the absorption tower 2; a first 28 and a second densimeter flange 29 are respectively arranged on the jet aeration tower 1 and the SO 2 The middle lower side wall of the absorption tower 2; a reabsorption slurry merging pipe 30 is provided at a lower side wall of the jet aeration tower 1; a first 31 and a second 32 (the number is 2) low-level slurry discharge pipes are respectively arranged in the jet aeration tower 1 and the SO 2 The bottom of the absorption tower 2; the acid liquid feeding pipe 33 is arranged at the bottom of the jet aeration tower 1; the first manhole 34 and the second manhole 35 are respectively arranged on the jet aeration tower 1 and the SO 2 The lower side wall of the absorption column 2.
The inlet of the first slurry pump 5 is connected with a first high-level 22 and low-level slurry discharge pipe 31 (the number is 2) and a clear water pipe (not in the scope of the patent) through a four-way pipeline, and the outlet is connected with the slurry inlet of the first jet aerator 3 (the number is 2) and a gypsum dehydration unit (not in the scope of the patent) through a three-way pipeline; the inlet of the second slurry pump 6 is connected with a second high-level slurry discharge pipe 23, a low-level slurry discharge pipe 32 (the number is 2) and a clear water pipe (which does not belong to the scope of the patent) through a four-way pipeline, and the outlet is connected with the slurry inlet of the second jet aerator 4 (the number is 2) and a reabsorption slurry merging pipe 30 through a three-way pipeline; the outlets of the first 7 and the second blower 8 are respectively connected with the air inlets of the first 3 and the second jet aerator 4 (the number is 2) through a first 14 and a second oxidation air pipe 15 (the number is 2); the inlet of the second blower 8 is connected with the first exhaust pipe 16; the outlet of the acid pump 9 is connected with an acid liquid feeding pipe 33; the first 12 and the second flexible joint 13 are respectively connected with the first 10 and the second desulfurization ash feeding pipe 11.
Jet aeration tower 1 and SO 2 The absorption towers 2 are vertical cylinders, the height-diameter ratio is 2-10, and guide plates are arranged in the inner wall areas facing the nozzles of the first jet aerator 3 and the second jet aerator 4.
The number of the first jet aerator 3 and the second jet aerator 4 is 2, and single nozzles and central symmetrical arrangement modes are adopted.
The first blower 7 and the second blower 8 are respectively Roots blower or centrifugal blower.
The acid liquid pump 9 adopts a metering pump.
The first 12 and the second 13 flexible joints are mainly made of rubber bellows.
The number of the first pH probe flange 24 and the second pH probe flange 25 is 3-10, and the first pH probe flange and the second pH probe flange are respectively arranged along the jet aeration tower 1 and the SO 2 The absorption towers 2 are arranged at equal intervals from top to bottom in the height direction.
The second exhaust pipe 17 is provided with SO 2 And an on-line monitoring device.
The operation treatment method of the dry method and semi-dry method desulfurization ash central symmetry jet oxidation tower is characterized by comprising the following steps of: the method comprises the following eleven steps:
step one: and (5) analyzing and testing raw materials. Analyzing and testing the components of the dry and semi-dry desulfurization ash to determine CaSO therein 3 And the content of various strongly basic compounds.
Step two: alkali liquor preparation. Only the inlet clear water pipeline and the outlet aerator pipeline of the second slurry pump 6 are opened, and the second slurry pump 6 is utilized to pump SO 2 Injecting clear water into the absorption tower 2, opening an inlet high-level slurry pipeline of the second slurry pump 6 when the liquid level is higher than that of the second high-level slurry discharge pipe 23, and closing the inlet clear water pipeline; feeding the desulfurization ash into the SO through the second flexible joint 13 and the second desulfurization ash feeding pipe 11 by using a pipe chain or a screw conveyor 2 An absorption tower 2; removal just into the towerThe sulfur ash is immediately sucked into the second slurry pump 6 and is sprayed out by the nozzle of the second jet aerator 4, the rapid and sufficient mixing and dissolving process with the clean water are completed, and finally the pH value is formed>10; stopping feeding the desulfurized fly ash, opening the inlet low-level slurry pipeline of the second slurry pump 6, and closing the inlet high-level slurry pipeline.
Step three: acid liquor preparation. Waste sulfuric acid with low heavy metal and organic pollutant content and mass fraction of 1% -95% is gradually injected into the jet aeration tower 1 by utilizing the acid pump 9; only an inlet clear water pipeline and an outlet aerator pipeline of the first slurry pump 5 are opened, and clear water is injected into the jet aeration tower 1 by using the first slurry pump 5; stopping feeding the waste sulfuric acid and the clean water after the pH value of the solution in the tower is stabilized between 2.2 and 4.2 and the liquid level is higher than that of the first high-level slurry discharge pipe 22; and opening an inlet high-level slurry pipeline of the first slurry pump 5, and closing an inlet clear water pipeline.
Step four: and (5) desulfurizing and acidifying. Feeding the desulfurized fly ash into the jet aeration tower 1 through the first flexible joint 12 and the first desulfurized fly ash feed pipe 10 by using a pipe chain or a screw conveyor; the desulfurized fly ash just entering the tower is immediately sucked into the first slurry pump 5 and is sprayed out by the nozzle of the first jet aerator 3, and the rapid and sufficient mixing, dissolving and reacting process with the acid liquor is completed; and stopping feeding the desulfurization ash when the pH value of the solution is raised to 3.1-6.2 and is kept stable.
Step five: and (5) forced oxidation. Opening an inlet low-level slurry pipeline of the first slurry pump 5, and closing an inlet high-level slurry pipeline; the first jet aerator 3 sucks air through the first oxidation air pipe 14 and sprays the air and the solution in the fourth step through a nozzle to finish multiphase mixing and efficient mass transfer process, and HSO in the solution is discharged at the moment 3 - Will be O 2 Oxidation to SO 4 2- Releasing H + Thereby lowering the pH of the solution; when the suction provided by the first jet aerator 3 is insufficient, the first blower 7 is started to provide enough power for the air.
Step six: and (5) secondary acidification. When the pH value of the solution in the fifth step tends to be stable, starting the acid liquid pump 9, and gradually adding the waste sulfuric acid in the fourth step into the jet aeration tower 1; immediately sucking the waste sulfuric acid which just enters the tower into a first slurry pump 5, spraying the waste sulfuric acid by a nozzle of a first jet aerator 3, completing the rapid and sufficient mixing and reaction process with the solution, reducing the pH value of the solution to be between 2.2 and 4.2 again, and then closing an acid liquid pump 9; and opening an inlet high-level slurry pipeline of the first slurry pump 5, and closing an inlet low-level slurry pipeline.
Step seven: a multi-step cycle. Repeating the steps four to six continuously to ensure that the solution in the step six gradually has solid-phase CaSO 4 Separating out and finally forming the slurry with the solid content of 6% -30%.
Step eight: and partially discharging slurry. When the slurry liquid level or density in the step seven reaches a certain value, opening an inlet low-level slurry pipeline and an outlet dewatering unit pipeline of the first slurry pump 5, closing an inlet high-level slurry pipeline and an outlet aerator pipeline, discharging a part of slurry by using the first slurry pump 5, and delivering the slurry into a dewatering unit to produce gypsum products; the liquid level in the jet aeration tower 1 is kept higher than the first high-level slurry discharge pipe 22 in the slurry discharge process; after the slurry discharge is completed, an inlet high-level slurry pipeline and an outlet aerator pipeline of the first slurry pump 5 are opened, and an inlet low-level slurry pipeline and an outlet dehydration unit pipeline are closed.
Step nine: SO (SO) 2 And (5) re-absorption. In multi-step cyclic oxidation, especially secondary acidification, there may be local pH of the slurry that is too low, resulting in incompletely oxidized SO 3 2- With excess H + Binding to release SO 2 In the case of (a), this part of SO 2 Will be discharged through said first exhaust pipe 16; the second jet aerator 4 uses a second oxidation air pipe 15 to carry out the partial SO 2 Sucking and spraying the mixed solution and alkaline slurry from the second step through a nozzle to realize multiphase mixing and efficient mass transfer to complete SO 2 A reabsorption process; when the suction provided by the second jet aerator 4 is insufficient, the second blower 8 is started to entrain SO 2 Providing sufficient power for the airflow.
Step ten:and (5) merging the reabsorption slurry. With the alkaline slurry of the second step continuously absorbing SO 2 The pH value of the water is gradually reduced; when the pressure is reduced to below 8.5, and after the secondary acidification in the step six is completed, opening an outlet reabsorption slurry merging pipeline of the second slurry pump 6, closing an outlet aerator pipeline, and sending alkaline slurry into the jet aeration tower 1 by using the second slurry pump 6; and opening the inlet low-level slurry pipeline of the first slurry pump 5, closing the inlet high-level slurry pipeline, and performing merging oxidation treatment.
Step eleven: and finishing the modification. And continuously repeating the second step, the fourth step and the tenth step, and finally finishing the centrosymmetric jet oxidation of all the dry-method and semi-dry-method desulfurized ash.
The raw components of semi-dry desulfurization ash in a certain iron and steel plant are shown in table 1. The pH regulation acidification and forced oxidation test are carried out according to the step method of the invention, and when the solid content of the final slurry reaches 10%, the final slurry is derived from CaSO 3 The S balance of (2) is shown in figure 3. Table 2 shows the components of the oxidized products obtained. It can be seen that the main component in the original semi-dry desulfurization ash is CaSO 3 And CaCO (CaCO) 3 Respectively 39.65% and 32.77%, and a certain amount of MgCO 3 And Ca (OH) 2 Iso-overbased components, caSO 4 Is very low. By the step method, almost all CaSO in the original semi-dry desulfurization ash 3 、CaCO 3 And Ca (OH) 2 Are all converted into dihydrate CaSO 4 Simultaneous SO 2 Has little escape amount, and the dihydrate CaSO in the oxidized product 4 The content of the modified polyethylene reaches 93.97%, and a good modification effect is obtained.
TABLE 1 raw ingredients of semi-dry desulfurization ash (dry basis)
Figure DEST_PATH_IMAGE002
TABLE 2 composition of oxidized products (dry basis)
Figure DEST_PATH_IMAGE004
The embodiments described above are intended to facilitate a thorough understanding and enabling use of the invention by those skilled in the art. It will be apparent to those having ordinary skill in the art that the general principles described herein may be applied to other embodiments without the need for inventive faculty by various modifications to these embodiments. Therefore, the present invention is not limited to the above-described embodiments, and modifications made by those skilled in the art without departing from the scope of the invention should be included in the scope of the invention in light of the present teachings.

Claims (9)

1. A dry method and semi-dry method desulfurization ash central symmetry jet oxidation tower is characterized in that: the whole device consists of a jet aeration tower and SO 2 The device comprises an absorption tower, a first jet aerator, a second jet aerator, a first slurry pump, a second slurry pump, a first blower, a second blower, an acid pump, a first desulfurization ash feed pipe, a second desulfurization ash feed pipe, a first flexible joint, a second flexible joint, a first oxidation air pipe, a second oxidation air pipe, a first exhaust pipe, a second exhaust pipe, a first liquid level meter flange, a second liquid level meter flange, a first pressure meter flange, a second pressure meter flange, a first high-level slurry discharge pipe, a second high-level slurry discharge pipe, a first pH probe flange, a second pH probe flange, a first thermometer flange, a second thermometer flange, a first densimeter flange, a second densimeter flange, a reabsorption slurry merging pipe, a first low-level slurry discharge pipe, a second low-level slurry discharge pipe, an acid liquid feed pipe, a first manhole and a second manhole;
the number of the first jet aerator and the second jet aerator is 2, and the first jet aerator and the second jet aerator are respectively arranged on the jet aeration tower and the SO 2 The inner low position of the absorption tower takes the center of the bottom surface as a symmetrical point and is arranged in a central symmetry way; the first desulfurization ash feeding pipe, the first flexible joint, the first oxidation air pipe, the first exhaust pipe, the first liquid level meter flange and the first pressure meter flange are arranged at the top of the jet aeration tower; the second desulfurized ash feed pipe, the second flexible joint, the second oxidation air pipe, the second exhaust pipe, the second liquid level meter flange and the second pressure meter flange are arranged on the SO 2 Of absorption towersA top; the first and the second high-order slurry discharge pipes are respectively arranged on the jet aeration tower and the SO 2 An upper side wall of the absorption tower; the first pH probe flange and the second pH probe flange are respectively and equidistantly arranged on the jet aeration tower and the SO from top to bottom 2 The side wall of the absorption tower; the first thermometer flange and the second thermometer flange are respectively arranged on the jet aeration tower and the SO 2 The side wall of the middle part of the absorption tower; the first densimeter flange and the second densimeter flange are respectively arranged on the jet aeration tower and the SO 2 The side wall of the middle lower part of the absorption tower; the reabsorption slurry merging pipe is arranged on the side wall of the lower part of the jet aeration tower; the first and the second low-level slurry discharge pipes are respectively arranged on the jet aeration tower and the SO 2 The bottom of the absorption tower; the acid liquor feeding pipe is arranged at the bottom of the jet aeration tower; the first manhole and the second manhole are respectively arranged on the jet aeration tower and the SO 2 The lower side wall of the absorption tower;
the inlet of the first slurry pump is connected with the first high-position slurry discharge pipe, the first low-position slurry discharge pipe and the clear water pipe through four-way pipelines, and the outlet of the first slurry pump is connected with the slurry inlet of the first jet aerator and the gypsum dehydration unit through three-way pipelines; the inlet of the second slurry pump is connected with a second high-position slurry discharge pipe, a second low-position slurry discharge pipe and a clear water pipe through a four-way pipeline, and the outlet of the second slurry pump is connected with the slurry inlet of the second jet aerator and the reabsorption slurry merging pipe through a three-way pipeline; the outlets of the first blower and the second blower are respectively connected with the air inlets of the first jet aerator and the second jet aerator through the first oxidation air pipe and the second oxidation air pipe; the inlet of the second air blower is connected with the first exhaust pipe; the outlet of the acid liquor pump is connected with an acid liquor feeding pipe; the first flexible joint and the second flexible joint are respectively connected with the first desulfurization ash feeding pipe and the second desulfurization ash feeding pipe.
2. The dry, semi-dry desulfurization ash central symmetry jet oxidation tower according to claim 1, wherein: the jet aeration tower and SO 2 The absorption towers are vertical cylinders, the height-diameter ratio is 2-10, and guide plates are arranged in the inner wall areas opposite to the first jet aerator nozzle and the second jet aerator nozzle.
3. The dry, semi-dry desulfurization ash central symmetry jet oxidation tower according to claim 1, wherein: the number of the first jet aerator and the second jet aerator is 2, and the single nozzle and the central symmetrical arrangement mode are adopted.
4. The dry, semi-dry desulfurization ash central symmetry jet oxidation tower according to claim 1, wherein: the first blower and the second blower are respectively Roots blower or centrifugal blower.
5. The dry, semi-dry desulfurization ash central symmetry jet oxidation tower according to claim 1, wherein: the first flexible joint and the second flexible joint are both made of rubber corrugated pipes.
6. The dry, semi-dry desulfurization ash central symmetry jet oxidation tower according to claim 1, wherein: the number of the flanges of the first pH probe and the second pH probe is 3-10, and the flanges are respectively arranged along the jet aeration tower and the SO 2 The absorption towers are arranged at equal intervals from top to bottom in the height direction.
7. The dry, semi-dry desulfurization ash central symmetry jet oxidation tower according to claim 1, wherein: the second exhaust pipe is provided with SO 2 And an on-line monitoring device.
8. The dry, semi-dry desulfurization ash central symmetry jet oxidation tower according to claim 1, wherein: the acid liquid pump adopts a metering pump.
9. A method for operating a dry, semi-dry desulfurization ash central symmetry jet oxidation tower according to claim 1, which is characterized in that: the method comprises the following eleven steps:
step one: analyzing and testing raw materials, and analyzing and testing components of dry-method and semi-dry-method desulfurization ash to determine CaSO therein 3 And the content of various strong alkaline compounds;
step two: alkali liquor configuration, namely opening only an inlet clear water pipeline and an outlet aerator of the second slurry pumpPipeline for supplying SO to the furnace by using a second slurry pump 2 Injecting clear water into the absorption tower, opening an inlet high-level slurry pipeline of the second slurry pump when the liquid level is higher than that of the second high-level slurry discharge pipe, and closing the inlet clear water pipeline; feeding the desulfurized fly ash into the SO through the second flexible joint and the second desulfurized fly ash feed pipe by using a pipe chain or a screw conveyor 2 An absorption tower; the desulfurized ash just entering the tower is immediately sucked into a second slurry pump and is sprayed out by a nozzle of a second jet aerator, the rapid and sufficient mixing and dissolving process with the clean water are completed, and finally the pH value is formed>10; stopping feeding the desulfurized ash, opening an inlet low-level slurry pipeline of the second slurry pump, and closing an inlet high-level slurry pipeline;
step three: acid liquor preparation, namely gradually injecting waste sulfuric acid with low heavy metal and organic pollutant content and mass fraction of 1% -95% into the jet aeration tower by using the acid liquor pump; only opening an inlet clear water pipeline and an outlet aerator pipeline of the first slurry pump, and injecting clear water into the jet aeration tower by using the first slurry pump; stopping feeding the waste sulfuric acid and the clean water after the pH value of the solution in the tower is stabilized between 2.2 and 4.2 and the liquid level is higher than that of the first high-level slurry discharge pipe; opening an inlet high-level slurry pipeline of the first slurry pump, and closing an inlet clear water pipeline;
step four: the desulfurization ash is acidified, and the desulfurization ash is sent into a jet aeration tower through the first flexible joint and the first desulfurization ash feeding pipe by using a pipe chain or a screw conveyor; the desulfurized ash just entering the tower is immediately sucked into a first slurry pump and is sprayed out by a nozzle of a first jet aerator, so that the rapid and sufficient mixing, dissolving and reacting processes with the acid liquor are completed; stopping feeding the desulfurized fly ash when the pH value of the solution rises to 3.1-6.2 and keeps stable;
step five: forced oxidation, opening an inlet low-level slurry pipeline of the first slurry pump, and closing an inlet high-level slurry pipeline; the first jet aerator sucks air through a first oxidation air pipe and sprays the air and the solution in the fourth step through a nozzle to finish multiphase mixing and efficient mass transfer processes, and at the moment, HSO in the solution is discharged 3 - Will be O 2 Oxidation to SO 4 2- Releasing H + Thereby lowering the pH of the solution; when the suction force provided by the first jet aerator is insufficient, the first air blower is started to provide enough power for air;
step six: when the pH value of the solution in the fifth step tends to be stable, starting the acid liquid pump, and gradually adding the waste sulfuric acid in the fourth step into the jet aeration tower; immediately sucking the waste sulfuric acid which just enters the tower into a first slurry pump, spraying the waste sulfuric acid out of the tower through a nozzle of a first jet aerator, completing the rapid and sufficient mixing and reaction process with the solution, reducing the pH value of the solution to be between 2.2 and 4.2 again, and then closing an acid liquid pump; opening an inlet high-level slurry pipeline of the first slurry pump, and closing an inlet low-level slurry pipeline;
step seven: a multi-step circulation is carried out, the steps four to six are repeated continuously, so that the solution in the step six gradually has solid-phase CaSO 4 Separating out and finally forming slurry with the solid content of 6% -30%;
step eight: when the slurry liquid level or density in the step seven reaches a certain value, opening an inlet low-level slurry pipeline and an outlet dewatering unit pipeline of the first slurry pump, closing an inlet high-level slurry pipeline and an outlet aerator pipeline, discharging a part of slurry by using the first slurry pump, and delivering the slurry to a dewatering unit to produce gypsum products; in the pulp discharging process, the liquid level in the jet aeration tower is kept higher than that of the first high-level pulp discharging pipe; after the slurry discharge is completed, opening an inlet high-level slurry pipeline and an outlet aerator pipeline of the first slurry pump, and closing an inlet low-level slurry pipeline and an outlet dehydration unit pipeline;
step nine: SO (SO) 2 Reabsorption, in the course of multi-step cyclic oxidation, especially secondary acidification, may occur where the local pH of the slurry is too low, resulting in incompletely oxidized SO 3 2- With excess H + Binding to release SO 2 In the case of (a), this part of SO 2 Discharging through said first exhaust pipe; the second jet aerator uses a second oxidation air pipe to oxidize the part of SO 2 Sucking in and mixing it with the alkaline slurry of the second stepThe liquid is sprayed out by the nozzle to realize multiphase mixing and high-efficiency mass transfer to finish SO 2 A reabsorption process; when the suction provided by the second jet aerator is insufficient, the second blower is started to entrain SO 2 Providing sufficient power for the airflow of (a);
step ten: and (3) merging the reabsorption slurry, and continuously absorbing SO along with the alkaline slurry in the second step 2 The pH value of the water is gradually reduced; when the pressure is reduced to below 8.5, and after the secondary acidification in the step six is completed, opening an outlet reabsorption slurry merging pipeline of the second slurry pump, closing an outlet aerator pipeline, and sending alkaline slurry into a jet aeration tower by using the second slurry pump; opening an inlet low-level slurry pipeline of the first slurry pump, closing an inlet high-level slurry pipeline, and performing merging oxidation treatment;
step eleven: and (3) finishing the modification, continuously repeating the second step, the fourth step and the tenth step, and finally finishing the centrosymmetric jet oxidation of all the dry-method and semi-dry-method desulfurized ash.
CN202111391305.6A 2021-11-23 2021-11-23 Dry method and semi-dry method desulfurization ash central symmetry jet oxidation tower and operation treatment method thereof Pending CN116139674A (en)

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