CN114904898B - System and method for self-enriching dioxin in fly ash - Google Patents
System and method for self-enriching dioxin in fly ash Download PDFInfo
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- CN114904898B CN114904898B CN202210624772.7A CN202210624772A CN114904898B CN 114904898 B CN114904898 B CN 114904898B CN 202210624772 A CN202210624772 A CN 202210624772A CN 114904898 B CN114904898 B CN 114904898B
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- 239000010881 fly ash Substances 0.000 title claims abstract description 263
- HGUFODBRKLSHSI-UHFFFAOYSA-N 2,3,7,8-tetrachloro-dibenzo-p-dioxin Chemical compound O1C2=CC(Cl)=C(Cl)C=C2OC2=C1C=C(Cl)C(Cl)=C2 HGUFODBRKLSHSI-UHFFFAOYSA-N 0.000 title claims abstract description 130
- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000010521 absorption reaction Methods 0.000 claims abstract description 58
- 239000000428 dust Substances 0.000 claims abstract description 17
- 230000000694 effects Effects 0.000 claims abstract description 5
- 238000006243 chemical reaction Methods 0.000 claims description 57
- 238000005260 corrosion Methods 0.000 claims description 34
- 238000009826 distribution Methods 0.000 claims description 15
- 238000007664 blowing Methods 0.000 claims description 7
- 238000007599 discharging Methods 0.000 claims description 7
- 230000009471 action Effects 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 5
- 238000000746 purification Methods 0.000 claims description 5
- 230000005484 gravity Effects 0.000 claims description 3
- 239000002699 waste material Substances 0.000 abstract description 13
- 238000004064 recycling Methods 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 118
- 239000004568 cement Substances 0.000 description 15
- 238000005516 engineering process Methods 0.000 description 8
- 230000015556 catabolic process Effects 0.000 description 6
- 238000006731 degradation reaction Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 5
- 239000003546 flue gas Substances 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 4
- 238000006065 biodegradation reaction Methods 0.000 description 3
- 239000010419 fine particle Substances 0.000 description 3
- 238000005243 fluidization Methods 0.000 description 3
- 238000005406 washing Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 229910001385 heavy metal Inorganic materials 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000000197 pyrolysis Methods 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 238000009423 ventilation Methods 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 235000019738 Limestone Nutrition 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000000498 ball milling Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000010882 bottom ash Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 238000006298 dechlorination reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000012717 electrostatic precipitator Substances 0.000 description 1
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- 230000007774 longterm Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000001782 photodegradation Methods 0.000 description 1
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- 238000010248 power generation Methods 0.000 description 1
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- 238000009284 supercritical water oxidation Methods 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
- B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
- B09B3/70—Chemical treatment, e.g. pH adjustment or oxidation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D45/00—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces
- B01D45/12—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by centrifugal forces
- B01D45/16—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by centrifugal forces generated by the winding course of the gas stream, the centrifugal forces being generated solely or partly by mechanical means, e.g. fixed swirl vanes
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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
- B01D53/02—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 by adsorption, e.g. preparative gas chromatography
- B01D53/06—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 by adsorption, e.g. preparative gas chromatography with moving adsorbents, e.g. rotating beds
- B01D53/10—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 by adsorption, e.g. preparative gas chromatography with moving adsorbents, e.g. rotating beds with dispersed adsorbents
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
- B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
- B04C9/00—Combinations with other devices, e.g. fans, expansion chambers, diffusors, water locks
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
- B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
- B09B3/40—Destroying solid waste or transforming solid waste into something useful or harmless involving thermal treatment, e.g. evaporation
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/20—Halogens or halogen compounds
- B01D2257/206—Organic halogen compounds
- B01D2257/2064—Chlorine
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
- B09B2101/00—Type of solid waste
- B09B2101/30—Incineration ashes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
- Y02A50/2351—Atmospheric particulate matter [PM], e.g. carbon smoke microparticles, smog, aerosol particles, dust
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Abstract
The invention belongs to the field of waste disposal and recycling, and particularly relates to a system and a method for self-enriching dioxin in fly ash. The system comprises a fly ash dioxin removal unit and a tail gas treatment unit; the fly ash and the hot air are continuously introduced into the fly ash dioxin removal unit and are in direct contact, the treated fly ash is discharged, and tail gas carrying dioxin escapes into the tail gas absorption tower; the tail gas absorption tower is filled with untreated fly ash, dioxin carried in the tail gas is adsorbed through the part of fly ash, and the fly ash rich in dioxin is discharged after the effect of absorbing the dioxin is not achieved; the gas enters the cyclone barrel to be subjected to dust removal treatment, and finally is discharged to the atmosphere through a fan. The invention fully utilizes the characteristics of the fly ash, uses waste to treat waste, and uses a small part of fly ash to remove most of dioxin in the fly ash.
Description
Technical Field
The invention belongs to the field of waste disposal and recycling, and particularly relates to a system and a method for self-enriching dioxin in fly ash.
Background
The household garbage incineration fly ash is generated in the municipal household garbage incineration process, and organic matters in garbage are mainly discharged in the form of gaseous matters in the garbage incineration process; the inorganic substances mainly form solid particles, wherein the larger particles are deposited on the bottom of the incinerator and the fire grate, and are called bottom ash, while the fine particles float in the flue gas and enter a flue gas purification system together with the flue gas, the particles form 50% of incineration fly ash, the rest of incineration fly ash is derived from limestone or activated carbon added in the flue gas purification process, the rest of incineration fly ash is commonly trapped in a dust remover (an electrostatic precipitator, a cloth bag dust remover and the like), and meanwhile, a part of fine particles are also deposited at the bottoms of a flue and a chimney, and the trapped and deposited fine particles are called incineration fly ash.
The fly ash contains trace heavy metals such as dioxin, cr, hg and the like, and is listed in the national hazardous waste directory (coded as HW 18). In recent years, the increment of household garbage is large, and the garbage incineration power generation industry is increased year by year, so that the fly ash amount is rapidly increased. The research shows that the concentration of PCDD/Fs in the fly ash and the toxicity equivalent are greatly different according to different factors such as the type of incineration waste, the type of incinerator, the incineration capacity, dust removal equipment and the like, and about half of the total amount of dioxin generated by an incineration source comes from the fly ash.
The disposal technology of dioxin in fly ash mainly comprises solidification landfill, low-temperature pyrolysis, high-temperature disposal, biodegradation, chemical removal and the like. "stabilization cure + landfill" does not degrade the dioxin in the fly ash, but only seals it off, and landfill is a potential source of dioxin emissions to nearby water environments. The degradation of dioxin can be realized by the technology of co-processing fly ash by high-temperature melting and cement kiln, but the economic value is not great because the energy consumption cost of the melting mode is too high. The disposal technology mainly adopted in China is a solidification landfill method and cement kiln cooperative disposal technology. Other techniques such as biodegradation, chemical removal and low temperature pyrolysis are currently mostly in the laboratory or pilot plant stage. The biodegradation method has the advantages of environmental friendliness, low cost and the like, but the degradation efficiency of the dioxin is relatively low; the chemical removal method can thoroughly treat the waste, and more treatment technologies are researched, including a redox dechlorination method, a photodegradation method, a catalytic oxidation method, a mechanical ball milling method, a microwave elimination method, a supercritical water oxidation method and the like.
Currently, the current state of the art for the co-disposal of fly ash in cement kilns in the industry is as follows: the chloride ions which have serious limitation on cement production are removed in advance through water washing, and then the fly ash after water washing is put into a high-temperature area of a cement kiln for incineration disposal, so that the purposes of degrading dioxin in the fly ash and solidifying heavy metals are achieved. The technology introduces the fly ash additive, which may reduce the addition amount of the cement raw material, and adopts a bypass air-release technology to avoid the skinning from affecting the normal production of the cement clinker, so that about 6% -10% of the flue gas with the temperature as high as 1000 ℃ is led out through the bypass air-release, thereby increasing the energy consumption.
Low temperature heat treatment degradation was first proposed by hagemaer, who considered that the following conditions must be met in order to ensure efficient degradation of dioxin: (1) anoxic conditions; (2) a reaction temperature of between 250 and 400 ℃; (3) residence time of 1h; (4) the discharge temperature is lower than 60 ℃. The defect is that the anaerobic environment restricts the continuous treatment, and the intermittent treatment is generally carried out in a closed reaction kettle.
In summary, the problems of the prior art are:
(1) The cement kiln is used for cooperatively disposing the fly ash, the fly ash can be disposed in large scale after chloride ions are removed by water washing pretreatment, and the method is limited to the cement kiln, particularly to cities without cement factories, and the disposal of household garbage is a problem facing each city.
(2) The ventilation quantity in the cement kiln has an optimal operation range, and after the ventilation quantity exceeds the optimal operation range, the problems of high-temperature fan power increase, cement yield reduction or waste quantity reduction in co-processing and the like are caused;
(3) The principle of low-temperature degradation of dioxin by fly ash requires anoxic, quenching and intermittent conditions, and the degradation tail gas of low-temperature heat treatment is not quenched to possibly synthesize dioxin again, so that a large amount of cold air is needed to be mixed or a large amount of cold water is consumed, which is not beneficial to saving water resources.
Disclosure of Invention
In order to solve the technical problems in the prior art, the invention provides a system and a method for self-enriching dioxin in fly ash, which fully utilize the characteristics of the fly ash, treat waste with waste and remove most of dioxin in fly ash with a small part of fly ash.
The technical scheme of the invention comprises the following steps:
a system for self-enriching dioxin in fly ash comprises a fly ash dioxin removal unit and a tail gas treatment unit;
the fly ash dioxin removing unit comprises a rotary kiln or a reaction kettle; a hot air inlet is formed in one side of the lower end of the fly ash dioxin removing unit, and a fly ash inlet and a tail gas outlet are formed in two opposite sides of the upper end; the fly ash inlet is used for introducing fly ash into the fly ash dioxin removal unit; a first anti-corrosion lining plate is arranged in the bottom area of the inner side of the fly ash dioxin removal unit, and a wind distribution hole with a hood structure is arranged on the first anti-corrosion lining plate; the fly ash inlet is arranged above the first anti-corrosion lining plate, the hot air inlet is arranged below the first anti-corrosion lining plate, hot air passes through the air distribution holes on the first anti-corrosion lining plate and contacts with the fly ash to form tail gas containing dioxin, and the tail gas is discharged to the tail gas treatment unit through the tail gas outlet; a fly ash treatment product discharge outlet is arranged at one side of the lower end of the fly ash dioxin removal unit;
the tail gas treatment unit comprises a tail gas absorption tower, a cyclone barrel and a fan; the internal structure of the tail gas absorption tower is the same as that of the fly ash dioxin removal unit, a second anti-corrosion lining plate is arranged in the tail gas absorption tower, and unreacted fly ash is contained above the second anti-corrosion lining plate; the tower wall of the tail gas absorption tower is respectively provided with a tail gas air inlet, a fly ash feed inlet, a fly ash discharge outlet and a tail gas discharge outlet from bottom to top; the fly ash feed inlet is positioned above the second anti-corrosion lining plate so as to introduce fly ash into the tail gas absorption tower; the tail gas air inlet is communicated with the tail gas outlet on the reaction kettle, hot tail gas containing dioxin enters the tail gas absorption tower from the reaction kettle, contacts with fly ash through a wind distribution hole on a second anti-corrosion lining plate below, and the part of fly ash rich in dioxin is discharged through a fly ash discharge port after the effect of absorbing the dioxin is not achieved;
the air inlet at the lower end of the cyclone is communicated with the tail gas outlet of the tail gas absorption tower, the tail gas treated by the fly ash in the tail gas absorption tower carries a small amount of fly ash to enter the cyclone for dust removal and purification, the fly ash is discharged through the discharge outlet at the bottom of the cyclone, and the tail gas after dust removal is discharged into the atmosphere through the exhaust outlet at the top of the cyclone under the action of the fan.
Further, a self-adjusting turning plate is arranged near one side of a tail gas outlet in the fly ash dioxin removal unit, and after part of tail gas carrying the fly ash and the dioxin impacts the turning plate, the fly ash falls into a reaction zone of the fly ash dioxin removal unit, and the tail gas escapes from the reaction zone from the top of the reaction kettle through the turning plate; meanwhile, part of tail gas carries fly ash to deposit at a tail gas outlet, after the fly ash is accumulated to a certain degree, the turning plate is rotated and opened under the action of gravity, and the fly ash falls into the fly ash dioxin removing unit again.
Further, the self-enrichment method of the self-enrichment system of dioxin in fly ash comprises the following steps:
s1, continuously blowing hot air into a fly ash dioxin removal unit to heat a reaction kettle to 350-650 ℃ and then keeping the reaction kettle for 30-120min; adding fly ash into a reaction kettle through a fly ash inlet, enabling hot air to be in direct contact with the fly ash at 0.5-1.5m/s, discharging the treated fly ash through a fly ash treatment product discharge port, and enabling tail gas carrying dioxin to escape into a tail gas absorption tower through a tail gas outlet;
s2, the untreated fly ash is arranged on a second anti-corrosion lining plate of the tail gas absorption tower, and the mass ratio of the fly ash in the tail gas absorption tower to the fly ash in the fly ash dioxin removal unit is (1:1) - (3:1); the dioxin carried in the tail gas is adsorbed through the fly ash in the tail gas absorption tower, and the part of fly ash rich in dioxin is discharged through a fly ash discharge port; the gas enters the cyclone barrel to be subjected to dust removal treatment, and finally is discharged to the atmosphere through a fan.
Further, the average grain diameter of fly ash in the tail gas absorption tower is 5-20 microns, and the maximum grain diameter is less than or equal to 150 microns, so that the best adsorption effect on dioxin is achieved.
Further, the concentration of dioxin contained in the fly ash before the treatment in S1 is 300-500 ng TEQ/kg, and the concentration of dioxin in the fly ash treatment product is reduced to 16-29ng TEQ/kg.
The invention has the advantages and positive effects that:
the invention avoids the limitation that the technology of cooperatively disposing the fly ash by a cement kiln in the prior art needs to wash the fly ash to reduce the chlorine content of more than 20% to be less than 1%, thereby realizing the removal of dioxin in the fly ash, and the dioxin in the fly ash can be disposed of without being in a city with a cement factory; anaerobic, quenching and intermittent conditions are not required.
According to the invention, the escaped tail gas possibly containing dioxin is directly discharged after being treated, so that the tail gas does not need to enter a cement kiln for treatment.
In order to avoid synthesizing dioxin again when the tail gas is directly discharged while removing dioxin in the fly ash, the invention utilizes the characteristics of small granularity, large specific surface and easy expansion fluidization of the fly ash, uses waste to treat waste, and uses untreated fly ash to adsorb tail gas containing dioxin in a tail gas treatment unit, thereby achieving the purposes that most part of fly ash (the fly ash led into the dioxin removal unit) removes dioxin, and a small part of residual fly ash (the fly ash in the tail gas treatment unit which is replaced after long-term use) enriches dioxin.
Description of the drawings:
FIG. 1 is a schematic diagram of a dioxin self-enrichment system of the present invention (solid line for fly ash flow direction and dotted line for gas flow direction);
in the figure; 1. a reaction kettle; 11. a hot air inlet; 12. a fly ash inlet; 13. a tail gas outlet; 14. a fly ash treatment product discharge outlet; 15. a first flap; 16. a first anticorrosion liner; 2. a tail gas absorption tower; 21. a second anti-corrosion lining plate; 22. a tail gas inlet; 23. a fly ash feed inlet; 24. a fly ash discharge port; 25. a tail gas outlet; 26. a second flap; 3. a cyclone; 4. a blower.
Detailed Description
The technical scheme in the embodiment of the invention is clearly and completely described below; obviously; the described embodiments are only a few embodiments of the present invention; but not all embodiments. Based on the embodiments in the present invention; all other embodiments obtained by those skilled in the art without undue burden; all falling within the scope of the present invention.
Example 1
The embodiment provides a system for self-enriching dioxin in fly ash, which comprises a fly ash dioxin removal unit and a tail gas treatment unit.
The fly ash dioxin removing unit can select a rotary kiln or a reaction kettle 1 with stirring, in this embodiment, the reaction kettle 1 is selected, one side of the lower end of the reaction kettle 1 is provided with a hot air inlet 11, two opposite sides of the upper end of the reaction kettle 1 are provided with a fly ash inlet 12 and a tail gas outlet 13, wherein the tail gas outlet 13 is arranged opposite to the hot air inlet 11, so that the tail gas containing dioxin is discharged after the hot air contacts with the fly ash. The fly ash inlet 12 is used for introducing fly ash into the reaction kettle 1; a fly ash treatment product discharge port 14 is arranged at one side of the lower end of the reaction kettle 1. A first anti-corrosion lining plate 16 is arranged in the inner bottom area of the reaction kettle 1, and a wind distribution hole with a hood structure is arranged on the first anti-corrosion lining plate 16; the hot air inlet 11 is arranged below the first corrosion-resistant lining plate 16, passes through the air distribution holes on the first corrosion-resistant lining plate 16, contacts with the fly ash, and removes dioxin in the fly ash. A self-adjusting turning plate is arranged near one side of the tail gas outlet 13, and after part of tail gas carrying with fly ash and dioxin impacts the turning plate, the fly ash can fall into a reaction zone at the lower part of the reaction kettle 1, and the tail gas escapes from the reaction zone from the turning plate to the top of the reaction kettle 1; meanwhile, part of the tail gas carries fly ash to deposit at the tail gas outlet 13, after the fly ash is accumulated to a certain degree, the turning plate is rotated and opened under the action of gravity, and the fly ash falls into the reaction kettle 1 again.
The tail gas treatment unit comprises a tail gas absorption tower 2, a cyclone cylinder 3 and a fan 4; the internal structure of the tail gas absorption tower 2 is the same as that of the reaction kettle 1, a second anti-corrosion lining plate 21 is arranged in the tail gas absorption tower 2, unreacted fly ash is contained on the second anti-corrosion lining plate 21, and the part of fly ash is consistent with the fly ash source of the reaction kettle 1; specifically, the tower wall of the tail gas absorption tower 2 is respectively provided with a tail gas air inlet 22, a fly ash feed inlet 23, a fly ash discharge outlet 24 and a tail gas discharge outlet 25 from bottom to top; the fly ash feed inlet 23 is positioned between the second anti-corrosion lining plates 21 so as to introduce fly ash into the tail gas absorption tower 2; the tail gas air inlet 22 is communicated with the tail gas outlet 13 on the reaction kettle 1, hot tail gas containing dioxin enters the tail gas absorption tower 2 from the reaction kettle 1 and contacts with fly ash through an air distribution hole on the second anti-corrosion lining plate 21 below, the characteristics of small granularity, large specific surface and easy expansion fluidization of the fly ash are utilized, waste is treated by waste, the dioxin in the tail gas is absorbed by the fly ash, and the part of the fly ash rich in dioxin is discharged through the fly ash discharge port 24 after the effect of absorbing the dioxin is not achieved. Preferably, the average grain diameter of the fly ash in the tail gas absorption tower is 5-20 microns, and the maximum grain diameter is less than or equal to 150 microns, so that the characteristics of small grain size, large specific surface and easy expansion fluidization of the fly ash are fully utilized, and dioxin in the tail gas is adsorbed as much as possible.
The air inlet on the side surface of the cyclone cylinder 3 is communicated with the tail gas outlet 25 of the tail gas absorption tower 2, a small amount of fly ash is carried in the tail gas treated by the fly ash in the tail gas absorption tower 2 to enter the cyclone cylinder 3 for dust removal and purification, the fly ash is discharged through the discharge outlet at the bottom of the cyclone cylinder 3, and the tail gas after dust removal is discharged through the exhaust outlet at the top of the cyclone cylinder 3 under the action of the fan 4.
Example 2
The invention is a method for self-enriching dioxin in fly ash by using the self-enriching system of the embodiment 1, which comprises the following steps:
s1, continuously blowing hot air into the reaction kettle 1, and keeping the reaction kettle 1 at 350 ℃ for 120min; adding fly ash with the concentration of 500ng TEQ/kg into the reaction kettle 1 through a fly ash inlet 12, enabling hot air to be in direct contact with the fly ash at 0.5m/s, discharging the treated fly ash through a fly ash treatment product discharge outlet 14, and detecting that the concentration of the dioxin in the part of fly ash treatment product is reduced to 35ng TEQ/kg; the tail gas carrying dioxin escapes into the tail gas absorption tower 2 through the tail gas outlet 13, and the wind speed of the wind distribution holes is kept at 10-30 m/s;
s2, the untreated fly ash with the concentration of 500 gTEQ/kg of dioxin is arranged on the anti-corrosion lining plate of the tail gas absorption tower 2, the part of fly ash is sent into the tail gas absorption tower 2 through a fly ash feed inlet 23, and the mass ratio of the fly ash in the tail gas absorption tower 2 to the fly ash in the reaction unit is 1:1, a step of; dioxin carried in the tail gas is adsorbed by the fly ash, and the part of the fly ash rich in dioxin is discharged through a fly ash discharge port 24; the gas enters the cyclone cylinder 3 for dust removal treatment and finally is discharged to the atmosphere through the fan 4.
Example 3
The invention is a method for self-enriching dioxin in fly ash by using the self-enriching system of the embodiment 1, which comprises the following steps:
s1, continuously blowing hot air into the reaction kettle 1, and keeping the reaction kettle 1 at 350 ℃ for 120min; adding the fly ash with the dioxin concentration of 400ng TEQ/kg into the reaction kettle 1 through a fly ash inlet 12, fully contacting hot air with the fly ash at 1m/s, discharging the treated fly ash through a fly ash treatment product discharge outlet 14, and detecting that the dioxin concentration in the part of fly ash treatment products is reduced to 23ng TEQ/kg; the tail gas carrying dioxin escapes into the tail gas absorption tower 2 through the tail gas outlet 13, and the wind speed of the wind distribution holes is kept at 10-30 m/s;
s2, the untreated fly ash with the dioxin concentration of 400ng TEQ/kg is arranged on the anti-corrosion lining plate of the tail gas absorption tower 2, the part of fly ash is sent into the tail gas absorption tower 2 through a fly ash feed inlet 23, and the mass ratio of the fly ash in the tail gas absorption tower 2 to the fly ash in the reaction unit is 3:1, a step of; dioxin carried in the tail gas is adsorbed by the fly ash, and the part of the fly ash rich in dioxin is discharged through a fly ash discharge port 24; the gas enters the cyclone cylinder 3 for dust removal treatment and finally is discharged to the atmosphere through the fan 4.
Example 3
The invention is a method for self-enriching dioxin in fly ash by using the self-enriching system of the embodiment 1, which comprises the following steps:
s1, continuously blowing hot air into the reaction kettle 1, and keeping the reaction kettle 1 at 650 ℃ for 30min after heating; adding fly ash with the concentration of 500ng TEQ/kg into the reaction kettle 1 through a fly ash inlet 12, fully contacting hot air with the fly ash at 1.5m/s, discharging the treated fly ash through a fly ash treatment product discharge port 14, and detecting that the concentration of the dioxin in the part of fly ash treatment product is reduced to 20ng TEQ/kg; the tail gas carrying dioxin escapes into the tail gas absorption tower 2 through the tail gas outlet 13, and the wind speed of the wind distribution holes is kept at 10-30 m/s;
s2, the untreated fly ash with the concentration of 500 gTEQ/kg of dioxin is arranged on the anti-corrosion lining plate of the tail gas absorption tower 2, the part of fly ash is sent into the tail gas absorption tower 2 through a fly ash feed inlet 23, and the mass ratio of the fly ash in the tail gas absorption tower 2 to the fly ash in the reaction unit is 1:1, a step of; dioxin carried in the tail gas is adsorbed by the fly ash, and the part of the fly ash rich in dioxin is discharged through a fly ash discharge port 24; the gas enters the cyclone cylinder 3 for dust removal treatment and finally is discharged to the atmosphere through the fan 4.
Example 5
The invention is a method for self-enriching dioxin in fly ash by using the self-enriching system of the embodiment 1, which comprises the following steps:
s1, continuously blowing hot air into the reaction kettle 1, and keeping the reaction kettle 1 at 650 ℃ for 30min after heating; adding fly ash with the concentration of 500ng TEQ/kg into the reaction kettle 1 through a fly ash inlet 12, fully contacting hot air with the fly ash at 1.5m/s, discharging the treated fly ash through a fly ash treatment product discharge port 14, and detecting that the concentration of the dioxin in the part of fly ash treatment product is reduced to 29ng TEQ/kg; the tail gas carrying dioxin escapes into the tail gas absorption tower 2 through the tail gas outlet 13, and the wind speed of the wind distribution holes is kept at 10-30 m/s;
s2, the untreated fly ash with the concentration of 500 gTEQ/kg of dioxin is arranged on the anti-corrosion lining plate of the tail gas absorption tower 2, the part of fly ash is sent into the tail gas absorption tower 2 through a fly ash feed inlet 23, and the mass ratio of the fly ash in the tail gas absorption tower 2 to the fly ash in the reaction unit is 3:1, a step of; dioxin carried in the tail gas is adsorbed by the fly ash, and the part of the fly ash rich in dioxin is discharged through a fly ash discharge port 24; the gas enters the cyclone cylinder 3 for dust removal treatment and finally is discharged to the atmosphere through the fan 4.
Example 6
The invention is a method for self-enriching dioxin in fly ash by using the self-enriching system of the embodiment 1, which comprises the following steps:
s1, continuously blowing hot air into the reaction kettle 1, and keeping the reaction kettle 1 at 650 ℃ for 30min after heating; adding the fly ash with the dioxin concentration of 300ng TEQ/kg into the reaction kettle 1 through a fly ash inlet 12, fully contacting hot air with the fly ash at 0.5m/s, discharging the treated fly ash through a fly ash treatment product discharge outlet 14, and detecting that the dioxin concentration in the part of the fly ash treatment product is reduced to 16ng TEQ/kg; the tail gas carrying dioxin escapes into the tail gas absorption tower 2 through the tail gas outlet 13, and the wind speed of the wind distribution holes is kept at 10-30 m/s;
s2, the untreated fly ash with the concentration of 500 gTEQ/kg of dioxin is arranged on the anti-corrosion lining plate of the tail gas absorption tower 2, the part of fly ash is sent into the tail gas absorption tower 2 through a fly ash feed inlet 23, and the mass ratio of the fly ash in the tail gas absorption tower 2 to the fly ash in the reaction unit is 3:1, a step of; dioxin carried in the tail gas is adsorbed by the fly ash, and the part of the fly ash rich in dioxin is discharged through a fly ash discharge port 24; the gas enters the cyclone cylinder 3 for dust removal treatment and finally is discharged to the atmosphere through the fan 4.
The present embodiment has been described in detail, but the content is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications within the scope of the present invention are intended to be covered by the present invention.
Claims (5)
1. A system for self-enriching dioxin in fly ash is characterized in that: comprises a fly ash dioxin removing unit and a tail gas treatment unit;
the fly ash dioxin removing unit comprises a rotary kiln or a reaction kettle; a hot air inlet is formed in one side of the lower end of the fly ash dioxin removing unit, and a fly ash inlet and a tail gas outlet are formed in two opposite sides of the upper end; the fly ash inlet is used for introducing fly ash into the fly ash dioxin removal unit; a first anti-corrosion lining plate is arranged in the bottom area of the inner side of the fly ash dioxin removal unit, and a wind distribution hole with a hood structure is arranged on the first anti-corrosion lining plate; the fly ash inlet is arranged above the first anti-corrosion lining plate, the hot air inlet is arranged below the first anti-corrosion lining plate, hot air passes through the air distribution holes on the first anti-corrosion lining plate and contacts with the fly ash to form tail gas containing dioxin, and the tail gas is discharged to the tail gas treatment unit through the tail gas outlet; a fly ash treatment product discharge outlet is arranged at one side of the lower end of the fly ash dioxin removal unit;
the tail gas treatment unit comprises a tail gas absorption tower, a cyclone barrel and a fan; the internal structure of the tail gas absorption tower is the same as that of the fly ash dioxin removal unit, a second anti-corrosion lining plate is arranged in the tail gas absorption tower, and unreacted fly ash is contained on the second anti-corrosion lining plate; the tower wall of the tail gas absorption tower is respectively provided with a tail gas air inlet, a fly ash feed inlet, a fly ash discharge outlet and a tail gas discharge outlet from bottom to top; the fly ash feed inlet is positioned above the second anti-corrosion lining plate so as to introduce fly ash into the tail gas absorption tower; the tail gas air inlet is communicated with the tail gas outlet on the reaction kettle, hot tail gas containing dioxin enters the tail gas absorption tower from the reaction kettle, contacts with fly ash through a wind distribution hole on a second anti-corrosion lining plate below, and the part of fly ash rich in dioxin is discharged through a fly ash discharge port after the effect of absorbing the dioxin is not achieved;
the air inlet at the side end of the cyclone is communicated with the exhaust outlet of the exhaust gas absorption tower, the exhaust gas treated by the fly ash in the exhaust gas absorption tower carries a small amount of fly ash to enter the cyclone for dust removal and purification, the fly ash is discharged through the discharge outlet at the bottom of the cyclone, and the exhaust gas after dust removal is discharged into the atmosphere through the exhaust outlet at the top of the cyclone under the action of the fan.
2. The system for self-enriching dioxin in fly ash according to claim 1, characterized in that: a self-adjusting turning plate is arranged near one side of a tail gas outlet in the fly ash dioxin removal unit, and after part of tail gas carrying the fly ash and the dioxin impacts the turning plate, the fly ash falls into a reaction zone of the fly ash dioxin removal unit, and the tail gas escapes from the reaction zone from the top of the reaction kettle through the turning plate; meanwhile, part of tail gas carries fly ash to deposit at a tail gas outlet, after the fly ash is accumulated to a certain degree, the turning plate is rotated and opened under the action of gravity, and the fly ash falls into the fly ash dioxin removing unit again.
3. A method for self-enrichment of dioxin in fly ash according to claim 1, comprising the steps of:
s1, continuously blowing hot air into a fly ash dioxin removal unit to heat a reaction kettle to 350-650 ℃ and then keeping the reaction kettle for 30-120min; adding fly ash into a reaction kettle through a fly ash inlet, enabling hot air to be in direct contact with the fly ash at 0.5-1.5m/s, discharging the treated fly ash through a fly ash treatment product discharge port, and enabling tail gas carrying dioxin to escape into a tail gas absorption tower through a tail gas outlet, wherein the wind speed of a wind distribution hole is kept at 10-30 m/s;
s2, the untreated fly ash is arranged on a second anti-corrosion lining plate of the tail gas absorption tower, and the mass ratio of the fly ash in the tail gas absorption tower to the fly ash in the fly ash dioxin removal unit is (1:1) - (3:1); the dioxin carried in the tail gas is adsorbed through the fly ash in the tail gas absorption tower, and the part of the fly ash rich in dioxin is accumulated to a certain degree and then is discharged through a fly ash discharge port; the gas enters the cyclone barrel to be subjected to dust removal treatment, and finally is discharged to the atmosphere through a fan.
4. The self-enrichment method of a dioxin self-enrichment system in fly ash according to claim 3, wherein the average particle size of the fly ash in the tail gas absorption tower is 5-20 microns, and the maximum particle size is less than or equal to 150 microns.
5. The self-enrichment method of a dioxin self-enrichment system in fly ash according to claim 3, wherein the concentration of dioxin contained in the fly ash before treatment in S1 is 300-500 ng TEQ/kg, and the concentration of dioxin in the fly ash treatment product is reduced to 16-29ng TEQ/kg.
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