Summary of the invention
The purpose of the present invention is to provide a kind of flue gas purification systems, can efficient removal dioxin, dust, NOx(nitrogen oxidationClose object), SO2(sulfur dioxide) etc. reduces the generation of dangerous waste.
Flue gas purification system provided by the invention, including TMSCR reactor, heat exchanger, SDA reactor, dust pelletizing system；InstituteState the entrance of the outlet connection heat exchanger of TMSCR reactor, the entrance of the outlet connection SDA reactor of heat exchanger, SDA reactorOutlet connect the dust pelletizing system；The TMSCR reactor includes filter, and filter core, filter core are provided in the filterInterior to have catalyst layer, the TMSCR reactor is used to filter dust and denitration, de- dioxin in flue gas；The SDAReactor is used to remove the sour gas in flue gas.
TMSCR reactor of the invention can be run at high temperature, and ammonium hydroxide, ammonium hydroxide and flue gas are sprayed into TMSCR reactorIt is mixed into filter, dust first is filtered by filter, it cannot be introduced into inside filter core, after mixed flue gas enters filter core inside,The catalyst action of catalyst layer in filter core, NOx(oxynitrides) reacts with ammonium hydroxide, generates N2 and water, and two dislikeYing Ze is completely decomposed into CO2, H2O and HCl under the effect of the catalyst, without reprocessing, and does not consume active carbon, removes99.9% dust, 95% NOx, 99.5% dioxin.SDA is cooled to by heat exchanger by the flue gas of TMSCR reactorTemperature needed for reactor carries out depickling processing in SDA reactor, and guarantee acid gas removal rate is 95% or more, thenFlue gas enters dust that dust pelletizing system generates depickling in addition to 99.9%.Place is dusted due to synchronizing in TMSCR reactorReason, substantially reduces the dust in flue gas, when so that flue gas entering heat exchanger, the low temperature of dioxin can not be carried out because lacking carbon sourcePredecessor catalysis reaction and de novo formation reaction.
For the de novo formation reaction for controlling dioxin, the synthesis of dioxin is reduced, further includes dry method spraying system, it is describedTMSCR reactor is connect by dry method spraying system with heat exchanger, that is, the outlet of TMSCR reactor and dry method spraying systemEntrance connection, the outlet of the dry method spraying system is connect with heat exchanger；The dry method spraying system is for further removing cigaretteThe removal of HCL in gas, HCL, so that the de novo formation reaction of dioxin lacks available chlorine source.Meanwhile when opening furnace, flue gasTemperature it is too low, TMSCR reactor is limited to the processing of flue gas, the present invention by dry method spraying system to flue gas carry out depickling,De- dioxin processing can also be carried out simultaneously, so that the flue gas emission between opening the furnace period can also be up to standard.
To further increase discharge standard, the invention also includes activated carbon adsorption system, the outlet of the dust pelletizing system withThe entrance of activated carbon adsorption system connects, the dioxin and sour gas that activated carbon adsorption system is adsorbed heavy metal and do not eliminatedBody.Activated carbon adsorption system of the present invention uses fixed bed form.
The present invention also provides a kind of flue gas purifying techniques, can efficient removal dioxin, dust, NOx(oxynitrides), SO2(sulfur dioxide) etc. reduces the generation of dangerous waste.
Flue gas purifying technique provided by the invention, flue gas initially enter TMSCR reactor, flue gas is dusted, denitration,De- dioxin；Cooling processing is carried out to the flue gas after TMSCR reactor for treatment；It is anti-that cooling treated flue gas is sent into SDADevice is answered, to deacidifying flue gas, treated that flue gas is dusted processing to depickling.
99.9% dust, 95% NO are removed in TMSCR reactorx, 99.5% dioxin.In SDA reactorCarry out depickling processing, guarantee acid gas removal rate 95% or more, then to flue gas ash removal, dust that depickling is generated in addition to99.9%.It is dusted processing due to synchronizing in TMSCR reactor, substantially reduces the dust in flue gas, so that flue gas entersWhen heat exchanger, the low temperature predecessor catalysis reaction and de novo formation reaction of dioxin can not be carried out because lacking carbon source.
For the de novo formation reaction for controlling dioxin, the synthesis of dioxin is reduced, to by TMSCR treated flue gas,De- HCL further first is carried out to flue gas using deacidification agent to handle, and then carries out cooling processing, the removal of HCL, so that dioxin againDe novo formation reaction lack available chlorine source.
Dry purification process will reach higher reactivity and gas-solid mixing consistency, and adsorbent must have biggish ratioThe consistency of surface area and granularity.Therefore, adsorbent sodium bicarbonate must be ground to certain fineness.The present invention is sprayed into flue gasEnter NaHCO3Or Ca (OH)2Powder carries out de- HCL processing, and the fineness of powder reaches 35 μm of D90 <, and the removal rate of HCL is reachable99%.
To avoid the filter core of TMSCR reactor from being blocked by dust, when the mistake for reaching setting time or TMSCR reactorThe filtering pressure drop of filter reaches setting value, carries out blow-back to the filter core of filter, removes the solid dust of cartridge surface.
To further increase discharge standard, the gas after dedusting is sent into activated carbon adsorption system, further dedusting, absorption twoDislike English and heavy metal.
Dustiness in activated carbon adsorption system outlet flue gas of the invention is less than 10mg/Nm3, NOxContent is less than 50mg/Nm3, SO2Content is less than 50mg/Nm3, HCL content is less than 10mg/Nm3, dioxins concentration is less than 0.1ng.TEQ/Nm3。
The present invention is adapted to the net of the flue gases of generations such as various rubbish, dangerous waste, biomass burning, metal smelt, coking of coalChange, it can efficient removal dioxin, dust, heavy metal, NOx(oxynitrides), SO2The acid such as (sulfur dioxide), HCl (hydrogen chloride)Property gas；And craft science is reasonable, operating cost is low；Low energy consumption, and energy utilization rate is high；Stable and reliable operation, easy to operate,Failure rate is low.
Multicomponent pollutant in high-efficiency multi-stage removing flue gas of the present invention, meets the following more harsh discharge standard: (1) systemProcess of uniting is simple, easy to maintain, and operating cost at least reduces 50% every year.(2) the complete catalytic pyrolysis dioxin of catalyst takes offExcept thorough, and removal efficiency > 99.5%, dangerous waste amount are few.(3) catalyst is protected by cartridge surface filter layer, and catalyst is avoided to loseEffect poisoning, average life span > 5 year.(4) semi-dry desulphurization, it is high-efficient, meet ultra-clean discharge standard.(5) denitration dust collecting efficiencyHeight, denitration efficiency greatly prolong active carbon in later active charcoal fixed bed up to 95%, gas dust content < 10mg/Nm3 after processingService life.(6) energy utilization rate is high, and flue-gas temperature can be reduced to 110 degree of discharges.(7) greatly reduce and belong to flying for dangerous wasteAsh quantity, the flying dust yield for belonging to dangerous waste is seldom, reduces the flying dust cost of disposal for belonging to dangerous waste, while it is low also to destroy dioxinThe condition of temperature synthesis, greatly reduces the original emission of dioxin, to realize that the near-zero release of dioxin creates favorably belowCondition.
Specific embodiment
The present invention using advanced high temperature TMSCR (too cotton catalyzed filter element integrated purifying) gas purification+dry method injection+SDA depickling+bag filter+activated carbon and fixed bed adsorption technology, can use between opening the furnace period dry method spray saleratus power intoRow depickling and de- dioxin, start main technique after smoke temperature is normal, are taken off simultaneously using TMSCR reactor in a temperature rangeNitre, de- dioxin and dedusting, spray SO in saleratus power and SDA efficient removal gas using dry method2And sour gas, utilize clothThe further dedusting of bag dust collector, the dioxin and sour gas for adsorbing heavy metal into activated carbon and fixed bed, not eliminating.
As shown in Figure 1, flue gas purification system of the invention include TMSCR reactor 1, dry method spraying system 2, heat exchanger 6,SDA reactor 3, bag filter 4, activated carbon adsorption system 5.
1, TMSCR reactor
In TMSCR reactor of the present invention, ammonium hydroxide is mixed with flue gas, the reaction of nitrogen oxides in ammonium hydroxide and flue gas, is realized de-Nitre.The denitration principle and SNCR of TMSCR reactor are essentially identical.
TMSCR reactor is mainly made of filter and Multifunctional filter element, and filter core packet layout is in filter head housings body.It is moreFunctional filter element is that the coating of nanoscale composite catalyst is sintered in shape inside the aluminium silicate salt composite structural filter of high porosityAt catalyst filtration layer (about 20 millimeters), de- dioxin, denitration and dedusting can be achieved at the same time.It is discharged according to GB18485-20143.5 definition to clinker in standard, the ash under TMSCR reactor can enter clinker, so really belonging to the flying dust of dangerous wasteAmount will greatly reduce.The too cotton high-temperature filter that Tai Mian company can be used in TMSCR reactor is realized.
The flue gas for being mixed with reducing agent (ammonium hydroxide etc.) enters reactor, by the filter core for the filter being mounted in reactorWhen, the dust in flue gas is intercepted at the surface filtration layer of filter core, and the flue gas after dedusting enters inside filter core, multiple inside filter coreUnder the catalyst action for closing catalyst layer, the NO in flue gasxN is generated by reaction2And vapor, dioxin, which is decomposed, generates CO2WithAfter vapor, reactor is discharged.The present invention passes through the dust that the cartridge surface of TMSCR reactor under purge gas blowback intercepts,On-line regeneration is realized to filter core.
(1) dedusting:
Dusty gas enters filter from dust removal filter lower part, enters filter core, solid dust quilt from the outer surface of filter materialFilter material is retained in the outer surface of filter material.Filtered clean gas passes upward through tube sheet discharge filter shell.It is arranged when reachingThe filtering pressure drop of setting blowback time or filter reaches setting value, starts blowback program, to filter core blowback.From filter in blowbackThe solid dust of wicking surface removing is deposited on the cone bottom dust accumulation room of filter.
The present invention used based on the time, was aided with pressure difference control blowback, i.e., filtering reaches setting time or pressure difference reaches and sets(initial setting is 30 minutes blowback periods and 2.5kPa blowback pressure differential resetting value to definite value, and two parameter is adjustable, not reach in advance personCarry out blowback), blowback is carried out automatically, without human intervention；TMSCR reactor is made of multiple groups filter core, every group of filter core setting onePlatform blowback pulse valve, timing control carries out online pulse cleaning to filter core when blowback carries out.
(2) denitration:
The present invention, according to the requirement of different load, is controlled ammonia inlet amount and is sent into reactor by metering and regulating device.Under catalyst action in filter core selectively with the NO in flue gasxIt chemically reacts, generates nitrogen and water.
4NO+4NH3+O2→4N2+6H2O (main reaction)
6NO2+8NH3→7N2+12H2O
(3) dioxin is taken off:
Dioxin is completely decomposed into CO under the effect of the catalyst2、H2O and HCl without reprocessing, and does not consume activityCharcoal.
For the working efficiency for improving TMSCR reactor, electric precipitator can be arranged in TMSCR reactor, utilize electric precipitationDevice is dusted operation to the dust in flue gas, is lowered into the dustiness of the flue gas of TMSCR reactor.
2, dry method spraying system
Using the dry FGD process reaction equation of sodium bicarbonate:
2NaHCO3=Na2Co3+H2O+CO2
NaHCO3+ HCl=NaCl+CO2+H2O
Na2CO3+SO3=Na2SO4+CO2
Na2CO3+ 2HCl=2NaCl+H2O+CO2
Na2CO3+ 2HF=2NaF+H2O+CO2
Dry method spraying system realizes flue gas dry cleaning technique, and sodium bicarbonate fine powder is injected directly into high-temperature flue gas, a sideAbsorption is directly reacted in face with acid contaminant, and on the other hand sodium bicarbonate decomposes and generates sodium carbonate Na at high temperature2CO3、H2O andCO2, further reacted with the acid contaminant in flue gas.Due to decomposing the sodium carbonate Na generated in high-temperature flue gas2CO3(particle is receivedRiceization) there is the reactivity of height generating moment, need to ensure being sufficiently mixed and reacting for high-temperature flue gas and adsorbent powder,Purifying property is ensured with slight excess of sodium bicarbonate.
Dry purification process will reach higher reactivity and gas-solid mixing consistency, and adsorbent must have biggish ratioThe consistency of surface area and granularity.Therefore before injecting flue, adsorbent sodium bicarbonate must be ground to certain fineness,Generally remove SO2, sodium bicarbonate fineness will reach D90 < 20 μm, then require D90 < 35 μm for removal HCl.Temperature when gas cleaningDegree can remove 95% or more SO at 200-300 DEG C or so2；The removal rate of HCl is up to 99%.
In short, adsorbent needs on-line operation with the flue gas dry cleaning equipment and system that sodium bicarbonate is primary raw material,The temperature parameter of compatible desulfurization dechlorination process, and process flow is simple, equipment is durable and system intelligent, it is net with other flue gasesChange mode is compared, its investment and operation cost is lower.It is of course also possible to use injection Ca (OH)2Mode.
3, SDA reactor and bag filter
SDA reactor desulfurization uses Ca (OH)2Powder makees absorbent, and SDA reactor and the prior art are almost the same.SDA is anti-Device is answered to match with bag filter, bag filter exit gas temperature is more than or equal to 150 DEG C when normal operation, and ensures tailPortion's flue gas does not condense.
Air leak rate of air curtain guarantee value≤2% of body of deduster；Running resistance design value≤1200Pa of deduster, guarantee value≤1500Pa.Dust remover roof maintenance door is double-layer structure, to prevent corrosion of the cool ambient air to upper box.Bag filter is setActive carbon jetting device is set, reaches discharge standard with harmful substances such as the contents that guarantees dioxin and heavy metal.Active carbon storageThere are in active carbon storehouse.
4, activated carbon adsorption system.
In the flue gas handled by previous process, containing harmful substances such as a small amount of dioxin and heavy metal, active carbon is inhaledAdsorption device can effectively remove the harmful substances such as dioxin and the heavy metal in flue gas, and flue gas emission is made to reach discharge index.
Activated carbon adsorption system uses fixed bed form.Effectively the dioxin contained in flue gas can be absorbed.For convenience of replacement, it is set as drawer type reactor, quickly active carbon used in adsorption tower can be replaced.Active carbonAdsorption system setting is effective to be kept the temperature to guarantee that temperature is maintained at the temperature most beneficial for active carbon absorption dioxin.In order to guaranteeIn the case where long-term, continuous operation, the high efficiency of active carbon, it is necessary to using high adsorption, high-intensitive active carbon.Prevent byEnter smoke stack emission in the active carbon powder carrying dioxin that intensity is inadequate to be generated and enters atmosphere.In order to reduce the resistance of systemPower, the present invention have selected column-shaped active carbon, while guaranteeing to come into full contact with flue gas, also effectively reduce the resistance of system.
Flue gas passes through TMSCR reactor first, removes 99.9% dust, 95% NOx, 99.5% dioxin.SoEnter dry method spraying system afterwards, carry out preliminary depickling, hydrogen chloride, hydrogen fluoride and sulphur oxidation can be removed in dry method spraying systemObject.Flue gas after dry-process deacidification enters boiler heat-exchanger, and smoke temperature is reduced to 160 degree and enters back into the further depickling of SDA reactor,When dry-process deacidification the complete deacidification agent of unreacted SDA reactor humidification after activity increase, and and injection depickling slurries together intoAcid gas removal is guaranteed that smoke temperature 95% or more, is reduced to 130 degree or so by acid gas removal rate by one step；Then cigaretteGas enters dust that bag filter generates depickling in addition to 99.9%；The flue gas that deduster comes out enters activated carbon adsorption systemThe dioxin and sour gas for adsorbing heavy metal, not eliminating；Then atmosphere is discharged into from chimney, realizes the discharge of flue gas ultra-clean.130Spend region and dust concentration it is low in the case where active carbon adsorption efficiency highest.Containing in activated carbon adsorption system outlet flue gasDust quantity is less than 10mg/Nm3, NOxContent is less than 50mg/Nm3, SO2Content is less than 50mg/Nm3, HCL content is less than 10mg/Nm3, twoIt dislikes English content and is less than 0.1ng.TEQ/Nm3。
Due to the higher cost of dry method spray technology, the present invention can be handled without dry method spraying system, that is, flue gas warpEnter heat exchanger after TMSCR reactor, SDA reactor is sent into after heat exchanger cools down.Handling by dry method spraying system more hasConducive to the ultra-clean discharge for realizing flue gas.
Between opening the furnace period, since temperature is lower, TMSCR reactor, SDA reactor temperature do not reach requirement, handle energyPower is lower, and the present invention can start dry method spraying system between opening the furnace period, using dry method injection saleratus power etc. carry out depickling andDe- dioxin, dioxin is adsorbed by saleratus power, and after smoke temperature is normal, flue gas is done through TMSCR reactor, SDA reactor for treatmentMethod spraying system is out of service, thus save the cost.
When ignition temperature be higher than 800 DEG C, when the residence time is more than 2s, in flue gas the resolution ratio of dioxin reach 99% withOn.Therefore, under the burning condition of good organization, guarantee that ignition temperature is higher than 800 DEG C and the residence time is greater than 2s, the overwhelming majorityEntering the dioxin that furnace rubbish is brought into can be decomposed, and seldom enter in incineration ashes.After dioxin majority in flue gas emission isThe catalysis reaction of phase low temperature predecessor generates or from the beginning reaction generates.
The low temperature predecessor mechanism of catalytic reaction of dioxin is generated between 200~500 DEG C: the low temperature forerunner of dioxinObject catalysis reaction include the heterocatalysis of the generation of gas phase predecessor, gas phase predecessor and ash surface absorption predecessor generate andThe generation of solid phase predecessor.The predecessor of low-temperature catalyzed reaction can be the chemical structures such as chlorophenol, chlorobenzene and dioxin is similarPredecessor is also possible to the not chlorinated organics of molecular structure dissmilarity, such as aliphatic compound, aromatic compound, acetyleneWith propylene etc..Chlorobenzene and chlorophenol are representative predecessor.Since flue-gas temperature is relatively low, the dioxin of gas phase reaction generationSeldom, it is 280~450 DEG C that PCDD/Fs, which most preferably generates temperature,.It is mainly ash surface catalysis in the dioxin that the temperature section generatesWhat effect generated.The present invention uses flying dust separating at high temperature technology, before key temperatures range, using TMSCR reactor dedusting,The fly ash content for reducing flue gas, can be effectively reduced the discharge of dioxin.In the prior art, dedusting is placed on technique back segment, is based onAsh surface catalytic action generates a large amount of dioxin, increases processing cost.
Dioxin can also be by the not similar compound such as polyvinyl chloride of chemical structure or such as polyphenyl of the organic matter without chlorineEthylene, cellulose, lignin, coal and granulated carbon react generation with chlorine source.More importantly the elements such as carbon, hydrogen, oxygen and chlorine pass throughElementary reaction generates dioxin, and the chlorine needed for de novo formation reaction, which is mainly reacted by DeaconProcess, to be generated, that is, is being catalyzedUnder the action of agent (Cu2+), it is transformed from HCl.When " denovo " reaction generates dioxin (300 DEG C of optimal reaction temperature), flyAsh can be counted as carbon source, catalyst and chlorine source.The oxidation reaction of carbon can form PCDDs and PCDFs on particle.HCl's depositsIt is being the necessary condition of dioxin de novo formation.The present invention is gone out HCL by dry method spraying system, reduces the amount of the HCL of flue gas,To destroy the condition that dioxin synthesizes again, it is finally reached the purpose for reducing dioxin.The dry method of the prior art sprays workSkill is arranged after SDA semidry method depickling, plays the role of assisting depickling, and the de novo formation reaction that can not solve dioxin is askedTopic.
The traditional handicraft contrast table of the present invention and background technique: