Background technology
To be a class connect 2 tricyclic aromatic organic compounds that the phenyl ring being replaced by chlorine forms by 2 or 1 oxygen atom to dioxin, comprises polychlorinated dibenzo-2 evil English and polychlorinated dibenzo, has 210 kinds of isomers/congeners.Dioxin is the highly stable lipophilicity solid chemical compound of a class, and its fusing point is higher, and decomposition temperature is greater than 700 ℃, and the utmost point is insoluble in water, dissolves in majority of organic solvent.Natural microbial degradation, hydrolysis and photolysis are less on the molecular structure impact of dioxin, are difficult to natural degradation.Some isomers in dioxin are extremely toxic substances, and its acute toxicity is equivalent to 1000 times of potassium cyanide.A large amount of zooperies show, the dioxin of very low concentrations just shows lethal effect to animal.The diseases such as dioxin also causes skin acne, has a headache, becomes deaf, melancholy, insomnia, and may cause chromosome damage, heart failure, cancer etc.Its greatest danger is to have irreversible teratogenesis, carcinogenic, mutagenic three intoxicatings.In addition, dioxin also affects reproductive function, and therefore disturbance endocrine system is known as " poison in century ".As height persistent pollutant, dioxin has strong compatibility to soil and bed mud, be easy to accumulate in biological tissue, and finally by food chain a large amount of enrichments in human body, and accumulate with more stable form.Once dioxin concentration of (especially women and children) in human body reaches certain value, the genotoxicity himself having, immunotoxicity and Endocrine toxicity will cause disease of skin, viscera disease, cancer and deformed child, affect the mankind's survival and development.
Dioxin is mainly not intended to produce in various pyroprocesses, for example, in the flue gas of waste incineration, metal smelt, cinerator etc., often contains the dioxin of higher concentration.In view of the toxicity of dioxin, each state has all made strict restriction to the discharge of dioxin.In China, industrial waste incinerator is lower than 1.0 ng I-TEQ/Nm
3, to the dioxin standard of medical waste incineration furnace, be lower than 0.5 ng I-TEQ/Nm
3.From 2008, the dioxin standard of Beijing was brought up to 0.1 ng I-TEQ/Nm comprehensively
3.The dioxin standard of developed country is normally lower than 0.1 ng I-TEQ/Nm
3.Soon, the dioxin standard of the domestic waste incineration of China will become lower than 0.1 ng I-TEQ/Nm
3.The formulation of stricter discharge standard, the fast lifting of the common people to the attention rate of environmental protection, to high temperature facilities such as operating and waste incineration facilities that be about to build up, has proposed stern challenge.How cheap and effectively control the discharge of dioxin, become a difficult problem in the urgent need to address.
The emission control of dioxin in pyroprocess, at the well-known control incineration temperature that passes through, on the basis of turbulivity and gas residence time, can also by inhibitor, suppress three approach of decomposition elimination of dioxin generation, absorption and separation dioxin and dioxin, further reduce the discharge of dioxin.
Article one, approach is in pyroprocess, to add to suppress the inhibitor that dioxin generates.For example, it is inhibitor that CN101725989A discloses a kind of sulphur, sulphur coal, calcium oxide, calcium hydroxide or calcium carbonate of being adopted as, and suppresses the method that in Refuse Incineration Process, dioxin generates.CN101485955 discloses and a kind of troilite and rubbish has been put in incinerator in the lump, by controlling the addition of troilite, suppresses the method that in Refuse Incineration Process, dioxin generates.CN201419076 discloses the method that realizes dioxin emission reducing by the control of the sulphur composition in coal.
Second approach is to adopt active carbon to absorb, and dioxin is separated from flue gas.CN201537442U discloses a kind of by spraying active carbon and calcium oxide and contact the device of the dioxin in absorption flue gas with flue gas is powerful in flue gas in venturi reactor.CN201949799U discloses a kind of device that adopts two cloth bags control dioxin, by venturi reactor, in first cloth bag, sprays into lime, in second cloth bag, sprays into active carbon.Improve active carbon and contact with flue gas, reach the object of effective absorption dioxin, and active carbon can reuse until dioxin saturated adsorption has reduced system operation cost.CN1246597 discloses by spray into active carbon in flue gas, then the Activated carbon separation that absorption is had to a dioxin out, delivers to combustion chambers burn and processes the method for eliminating dioxin.CN201997249U discloses and has adopted the discharge that reduces dioxin to the method that sprays into alkaline cooling fluid in flue gas.
Article three, approach is to decompose, and conventionally under the effect of catalyst, allows dioxin oxidation Decomposition at lower temperature.For example, CN1626277 discloses a kind of based on V
2o
5(WO
3, MoO
3) and TiO
2catalyst, can, at the temperature of 240-320 ℃, effectively remove the dioxin in flue gas.CN101559362 discloses first by TiO
2load on volcanic rock, and then supported V
2o
5, can at the temperature of 200-450 ℃, effectively remove dioxin.European patent (the patent No.: 634206) the disclosed catalyst that removes dioxin is also with TiO
2load barium oxide.United States Patent (USP) (the patent No.: 5227356) disclosed catalyst activity composition is transition metal oxide and noble metal.Japan Patent (the patent No.: 200024460 peace-11047592) disclosed catalyst activity component comprises metal oxide and the noble metals such as V, W, Cu, Mn, Cr, Pd, Ru, Pt, and catalyst carrier can be TiO
2, SiO
2, Al
2o
3, ZrO
2.The disclosed catalyst of Japan Patent (patent No.: flat-11226397) is the oxide that loads on the transition metal such as V, W on active carbon, Mo, Cu, Mn, Fe, Co, Cr, Ni.Also catalyst activity composition and polytetrafluoroethylene fibre can be prepared into the filter bag with catalytic activity, as CN101580973, CN101255615 and the United States Patent (USP) (patent No.: 5620669).In addition, CN201921634U discloses and has utilized ultraviolet emission device activation photocatalyst coating, reaches the object of catalytic decomposition of dioxins.CN101485958 discloses a kind of photo catalysis reactor and method for activating photocatalyst for the flue gas dioxin of degrading.Recently find, ozone can effectively promote the catalytic decomposition of dioxin, and for example, CN102814108A discloses ozone effect and promoted the low-temperature decomposition of dioxin on metal oxide catalyst.
But above patent, all exists some obvious shortcomings, for example, add inhibitor and conventionally can cause other pollution.The simple active carbon that uses absorbs dioxin technology, and not only active carbon is expensive, and has absorbed the active carbon after dioxin and must process as hazardous waste, or directly burns as fuel, and operating cost is high.Adopt catalysis filter bag technology, because pressure drop is too large, the flow velocity of flue gas is partially slow, and has the problem of catalyst loss, has increased equally operating cost.And catalytic decomposition technology faces equally that facility scale is huge, catalyst poisoning and need periodic replacement, flue gas to heat again, etc. problem.Even if adopt ozone to promote dioxin catalytic decomposition, face equally the still problem such as a large amount of uses of huge, ozone and catalyst periodic replacement of facility scale.
Summary of the invention
The purpose of this utility model is to provide a kind of device that removes dioxin in high-temperature flue gas of efficient cheapness.
Of the present utility modelly remove the device of dioxin in high-temperature flue gas and comprise the first cleaner, dioxins adsorption tower containing absorbent, the second cleaner, absorbent reclaims reactor and ozone generator, the exhanst gas outlet of the first cleaner is connected with the gas approach that contains the dioxins adsorption tower of absorbent, the exhanst gas outlet that contains the dioxins adsorption tower of absorbent is connected with the gas approach of the second cleaner, the exhanst gas outlet of the second cleaner is connected with chimney, the discharging opening that contains the dioxins adsorption tower of absorbent is connected with the charging aperture that absorbent reclaims reactor, the discharging opening of the second deduster is connected with the charging aperture that absorbent reclaims reactor, the discharging opening that absorbent reclaims reactor is connected with the charging aperture that contains the dioxins adsorption tower of absorbent, absorbent reclaims reactor and is connected with ozone generator.
The first above-mentioned cleaner can be sack cleaner, electric cleaner, cyclone dust collectors or their combination.The second described cleaner can be also sack cleaner, electric cleaner, cyclone dust collectors or their combination.
In the utility model, the described dioxins adsorption tower containing absorbent can be fixed bed absorption tower, fluid bed absorption tower or thermopnore absorption tower.
During work, first the flue gas after UTILIZATION OF VESIDUAL HEAT IN and chilling passes into the first cleaner, filters the particles such as flying dust of removing in flue gas in the first cleaner; Then enter the dioxins adsorption tower that contains absorbent, allow absorbent fully contact with flue gas, effectively the dioxin in absorption and separation flue gas.Utilize the absorbent dust containing dioxin that the second cleaner trap filter escapes from dioxins adsorption tower, after purification, reach the flue gas of national discharge standard from air flue emission.The absorbent dust of collecting from the second cleaner is sent into absorbent and is reclaimed reactor.In dioxins adsorption tower, having adsorbed dioxin reaches the saturated absorbent of absorption and is also fed to absorbent and reclaims in reactor.The ozone input absorbent that ozone generator is produced reclaims reactor, and at 25 ℃ ~ 350 ℃, reaction, utilizes the super oxidability of ozone and the catalytic activity of absorbent, and the dioxin being adsorbed on absorbent is thoroughly decomposed.Absorbent after processing is sent into dioxins adsorption tower, recycles.
Above-mentioned absorbent can be the active carbon of active carbon, CNT, process metal oxide modified or the CNT of process metal oxide modified, wherein metal oxide accounts for 0~50% of absorbent gross mass, and described metal oxide is one or more in the oxide of manganese, cerium, copper, vanadium, iron, molybdenum, tungsten, chromium or nickel.
Usefulness of the present utility model is: the device that removes the dioxin in high-temperature flue gas that the utility model is carried, simple in structure, absorbent is absorbed together with the advantages that dioxin and ozone promotes catalytic decomposition of dioxins, and not only absorbent can recycle but also the temperature of dioxin catalytic decomposition is low, facility scale is little, operating cost is low.And when utilizing catalytic decomposition of ozone dioxin, can not be subject to the impact of other compositions in flue gas, thereby reach the effect that efficiently removes at an easy rate the dioxin in high-temperature flue gas.Be applicable to comprise efficiently removing of dioxin in the high-temperature flue gas of waste incineration, smelting iron and steel, cement kiln, cinerator etc. and other volatile organic matter.