CN101394915A - Process for the treatment of offgas from sintering and pelletizing plants - Google Patents

Process for the treatment of offgas from sintering and pelletizing plants Download PDF

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Publication number
CN101394915A
CN101394915A CNA2007800070854A CN200780007085A CN101394915A CN 101394915 A CN101394915 A CN 101394915A CN A2007800070854 A CNA2007800070854 A CN A2007800070854A CN 200780007085 A CN200780007085 A CN 200780007085A CN 101394915 A CN101394915 A CN 101394915A
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China
Prior art keywords
waste gas
reactant
additive
adsorbent
fabric filter
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CNA2007800070854A
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CN101394915B (en
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A·弗莱尚德尔
R·纽霍尔德
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The Austrian limited liability company of primary metal science and technology
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Siemens VAI Metals Technologies GmbH Austria
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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
    • B01D53/46—Removing components of defined structure
    • B01D53/48—Sulfur compounds
    • B01D53/50—Sulfur oxides
    • B01D53/508—Sulfur oxides by treating the gases with solids
    • 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
    • B01D53/68—Halogens or halogen compounds
    • B01D53/685—Halogens or halogen compounds by treating the gases with solids
    • 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
    • B01D53/83—Solid phase processes with moving reactants

Abstract

A process for the treatment of offgas from sintering and pelletizing plants, in which dry additive is added to the offgas from a sintering or pelletizing plant upstream of a fabric filter (3), in particular in an offgas channel (2), and the additive is subsequently removed from the offgas by the fabric filter (3). The process is characterized in that the additive contains sodium hydrogencarbonate NaHCO3 as reagent and is at least partly recirculated into the offgas stream, in particular into the offgas channel (2), upstream of the fabric filter (3), is disclosed. This enables gas conditioning (cooling) as is necessary for a lime-containing reagent to be avoided.

Description

Processing is from the method for the waste gas of sintering and pelletizing equipment
The present invention relates to a kind of method of handling sintering and pelletizing equipment waste gas, wherein in the fabric filter upstream in waste gas, particularly in exhaust steam passage, add dried additive from sintering or pelletizing equipment, from waste gas, separate described additive by fabric filter then.
Particularly suitable agglomerating plant is an iron ore sintering equipment, and wherein the ore of sintering is used to pig iron manufacturing.Pelletizing equipment is used to produce the iron ore bead that uses for pig iron manufacturing.
The filter of bag hose, pocket filter, cloth filter, textile filter and metal fabric system all is included in the term fabric filter.
Here, additive is understood that the fresh additive both representing to contain reactant and also contain adsorbent in due course, again the material of expression recirculation.
In integrated metallurgical factory, the environment supervision mainly is primarily focused on agglomerating plant or the pelletizing equipment now.Its reason is (is generally 300000-1000000Nm because exhausted air quantity is very huge 3/ h), agglomerating plant has caused a big chunk of the pollutant emission of integrated metallurgical factory.Particularly fine dust and aerosol (salt) and heavy metal (Hg, Pb, Cd), organic emission, as Polychlorinated dioxin/furans, VOC, PAC, nitrogen oxide and acidic components as sulfur dioxide/sulfur trioxide, HCl and HF, have constituted may originating of problem.
At sintering or pelletizing equipment, during the normal running usually EGT below 140 ℃, promptly about 90-140 ℃.But, when operating trouble, may produce the temperature peak more than 200 ℃.
The equipment that is used to purify waste gas from sinter installations is disclosed, for example in the applicant's Austrian utility model AT8227U1.Yet wherein said method has been imagined cooling or wetting described waste gas in gas conditioner.In addition, also propose use quick lime or white lime and made reactant.
Thereby one object of the present invention is to improve known method and makes that the gas treatment that is used for purifying (particularly desulfurization) waste gas no longer is essential.This greatly reduces the cost of investment of this gas purifying equipment.
This purpose realizes by the method for claim 1.Write down favourable improvement of the present invention in the dependent claims.
Owing to contain main sodium acid carbonate NaHCO in the additive as reactant 3, NaHCO 3After becoming soda, thermal transition (activation) can directly react with most important component, and therefore needn't wetting again waste gas stream.Because NaHCO 3Be recycled at least in part in the waste gas stream of fabric filter upstream, particularly in the exhaust steam passage, so can guarantee NaHCO 3Well utilized.
NaHCO 3Also changed into sodium carbonate Na by coming in contact at first thus by thermal activation with hot waste gas 2CO 3(soda), and obtain to promote acidic components in reactant and the waste gas as far as possible complete reaction and can be used for adsorb pollutant greatly than (interior) surface area.In this transforms, form the highly porous property structure of soda particle.
2NaHCO 3+ heat → Na 2CO 3+ CO 2+ H 2O
With the important reaction of acid waste gas component be:
2NaHCO 3+SO 2+1/2 O 2→Na 2SO 4+H 2O+2CO 2
NaHCO 3+HCl→NaCl+H 2O+CO 2
NaHCO 3+HF→NaF+H 2O+CO 2
Na 2CO 3+SO 2+1/2 O 2→Na 2SO 4+CO 2
Na 2CO 3+2HCl→2NaCl+H 2O+CO 2
Na 2CO 3+2HF→2NaF+H 2O+CO 2
Because in the method for the invention needn't cooling exhaust, for later in sintering and pelletizing equipment situation with the downstream catalytic nitrogen rejection facility (SCR-DeNOx) that requires, also there is following extra advantage, promptly because higher exhausting waste gas temperature, the device that SCR-DeNOx is required is used for EGT is brought up to the operating temperature of requirement will be littler, and will be therefore more favourable aspect cost of investment and running cost.Owing to there is not moisture to be introduced into exhaust steam passage, there is the danger of caking hardly.
Adsorbent, as active carbon or open-hearth furnace coke HOK, the use in absorption heavy metal and PCDD/F can be greatly reduced, because NaHCO 3Or Na 2CO 3(soda) is because the loose structure that forms when activation has fettered to adsorptivity it greatly.
Since the outstanding stoichiometry of soda, CO when changing into soda 2From NaHCO 3On elimination, and the still less use of adsorbent is as mentioned above compared the residue that correspondingly produces less amount with the reactant of introducing with dry form that contains quick lime.Sometimes this can significantly improve running cost.
Though NaHCO 3In many incinerating waste material factories (MVA) and power station (KW), be used to purifying exhaust air, yet these processes has different exhaust gas conditions, 150 ℃ of promptly much higher EGTs (〉).In addition, waste gas is formed also different with sintering and pelletizing equipment.Therefore, for example hydrogen cloride concentration is higher for MVA and KW, is 10-100 times.So NaHCO 3Manufacturer (for example Solvay) also require for using NaHCO 3Carry out the waste gas purification EGT and be greater than 140 ℃, because only more than 140 ℃ NaHCO could take place fully 3To Na 2CO 3Required conversion.
Conversion rate depends primarily on EGT, and this temperature is high more, transforms (thermal activation) and carries out soon more.150 ℃ of these high temperature (〉) under, transform between several seconds kinds " on the spot " and promptly introduces just generation immediately of back.Require like this is because the NaHCO that is introduced 3To in electrofilter or fabric filter, separate and from this process, remove subsequently as product.But, for reaction volume that stoichiometry is promptly introduced remains on commercially beneficial level, NaHCO to the ratio of the acid gas components amount of separating 3Almost completely to transform be essential.
At sintering or pelletizing equipment, EGT particularly is usually less than 130 ℃ below 140 ℃ usually, is about 60-140 ℃, is generally 90-130 ℃, and is therefore in fact too low for known method.Yet because additive is recycled, particularly time of staying of high temperature range of 90-130 ℃ is extended NaHCO thus to additive at 60-140 ℃ in the method for the invention 3Conversion to soda can continue.Thereby the time of staying that lower temperature is more grown and/or the thinner NaHCO of quilt 3Lapping degree has been offset.
In pilot scale and laboratory research, find, can under 110 ℃ or lower temperature, carry out desulfurization, can significantly reduce heavy metal, PCDD/F and other organic pollution simultaneously and part reduces NOx with outstanding stoichiometry.
Comparison with the white lime desulfurization of routine:
Feature White lime Sodium acid carbonate NaHCO 3
The desulfurization degree 30-80% (depending on quality and gas treatment temperature) 90% (if necessary)
The stoichiometric factor of desulfurization (2.0-4.0 depending on the gentle body treatment temperature of reactant quality) 1.05-1.3
The residue amount that produces 100％ 60-70％
The reactant cost 100％ 140-200％
EGT after the gas purification 85-100℃ Almost identical with the exhaust gas entrance temperature
Gas cooled (reduction of EGT) 20-50℃ ～0℃
Quantity of sorbent 100％ 0-70％
The furnace gas amount that is used for denitrogenation 100％ 70-85％
Meet the following conditions then preferred especially sodium acid carbonate NaHCO if therefore compare with the limy reactant of use 3:
* require the height desulfurization
* the mean temperature of waste gas〉90 ℃
* the landfill cost high and in landfill treating capacity must keep very little
* being provided with catalysis denitrogenation (SCR-DeNOx) or its must be provided with subsequently in the gas purification downstream.
If selecting the degree of recirculation to make the mean residence time of the additive of new input is several hrs, particularly surpass one day, and just from system, remove then, can obtain good especially stoichiometry result.If wish to realize the short time of staying, then can pass through with NaHCO with constant good stoichiometry 3Being ground to suitable fineness reaches.For this reason, can design the fineness that makes reactant also only before using, just be ground to requirement soon with the transportation of coarse granule form.
If additive preferably is longer than half an hour as filter cake as far as possible longways before making with extra care, rest on the fabric filter, then can significantly improve NaHCO 3Quantitative conversion as far as possible.After being temporarily to store in the container, additive is introduced once more in the gas stream and in filter cake subsequently and is stopped the so long time once more.
Additive to waste gas stream with space that waste gas contacts in introducing preferably be designed to fly to flow through journey (Flugstromverfahren).
Fly to flow through journey and be interpreted as such process, promptly additive is added in the mobile waste gas, additive is carried by waste gas stream and mass transfer-reaction and/or the absorption of waste gas component to additive takes place in this course of conveying.The concentration of additive in the space that waste gas flows through is flying to flow through in the journey often lower, greatly about every cubic metre several milligrams to every cubic metre 100 scopes that restrain.Fixed bed, liquid bed, fine and close stream, fluid bed and fluosolids process on the contrary, wherein the concentration of additive in the space that waste gas flows through is in the scope of 1 kilogram every cubic metre or more additives approximately.
Fly to flow through the advantage of journey and pressure gas flow lower particularly in cost of investment and fall lowlyer, this has caused lower running cost.
Because additive is at least one point, preferably flowing to rightabout with waste gas or laterally in (cross-flow), introducing in the waste gas stream, the relative velocity between waste gas and the additive be improved and thus the reaction rate of additive and waste gas also be enhanced.At this, the relative velocity between additive and the waste gas in adverse current and cross-flow, be respectively at least 30m/s and at least 15m/s be effective especially.
Introduce at a plurality of somes place that flows to along waste gas if be designed to additive, then can add can be more equally distributed better than minor amounts of additives than once adding a large amount of additives at every turn.Reactant and adsorbent can spray into together or respectively.
A kind of scheme of the present invention is to introduce additive in a plurality of somes place that is dispersed on this cross section at least in a certain cross section of exhaust steam passage.Thereby, can guarantee additive on this cross section of exhaust steam passage more even distribution and guarantee the more good utilisation of additive thus, additive is consumed equably and the filter fabric is evenly loaded (filter cake evenly constitutes) thus.
Preferably additive is introduced by at least one jet pipe.Jet pipe is a tubule of additive being introduced waste gas.Described pipe is passable, for example, and perpendicular to stretching in the described passage and can randomly terminally flow on the rightabout crooked in the exhaust steam passage surface with waste gas.
Additive comprises NaHCO at least 3As reactant, and can comprise adsorbent such as open-hearth furnace coke or active carbon in addition.By described reactant, except separating acidic components such as SO 2, SO 3, outside HCl and the HF, can also fetter heavy metal and organic pollution.Described adsorbent can promote harmful constituent such as heavy metal and organic absorption constraint.If adsorbent and NaHCO 3Introduce together, it will be especially simple introducing.But, also can realize being introduced separately into.
Recycled materials is introduced favourable too with fresh adsorbent/reactant at different points.Thereby, can change their amount independently of one another, make additive obtain better utilization.Because adsorbent and possible reactant can both measure input targetedly, so can capture the contaminant gases peak value better by this way.
Adsorbent and/or reactant can also can introduced after it before the recycled materials.If adsorbent and/or reactant were introduced before recycled materials, then fresh adsorbent and/or reactant contact with the waste gas with high pollution substrate concentration that purifies not yet, and the recycled materials of partial reaction contacts with the waste gas with low pollutant load of part purification.
Especially, can design adsorbent is introduced as the function of the content of the content of condensable organic compound and/or heavy metal, and/or design makes reactant introduce as the function of the content of acidic components in the waste gas (particularly sulfur dioxide).
By accompanying drawing for example and illustrate the present invention, and in following specification, it is explained.
Fig. 1 has shown the device that is used to carry out the inventive method.
Fig. 2 has shown NaHCO 3To Na 2CO 3Conversion with the variation of temperature and particle diameter.
Fig. 3 has shown NaHCO 3To Na 2CO 3Conversion under constant particle diameter with variation of temperature.
According to shown in Figure 1, from the waste gas 1 of agglomerating plant in an advantageous manner by the process gas air blast with randomly be introduced into exhaust steam passage 2 by the pre-dedusting stage (electrofilter or cyclone dust collectors).Handling the required decompression (pressure according to equipment of the present invention falls) of waste gas is guaranteed by auxiliary blower 14.Exhaust steam passage 2 has constant basically cross section and the final fabric filter 3 that feeds.Certainly exhaust steam passage 2 needn't be orientated on level or vertical section.
Fresh additive is on the one hand as reactant NaHCO 3Introduce hopper 7 and be stored in the there, introduce hopper 8 and storage as adsorbent on the other hand.Described material is via swinging feeder (Zellradschleusen) discharging from hopper 7,8.With material input measuring container 9,10 separately.These measuring containers are weighed and liquid level sensor is installed.
Introducing the adsorbent or the reactant of measuring container 9,10 accurately controls quantitatively by metering screw.Adsorbent is via attached pipeline 12 inputs.Adsorbent is by means of carrying air 13 to be transferred to feeder 4 and spraying into exhaust steam passage 2 via the jet pipe of feeder 4.The reactant that is metered in quantitatively accurate mode (is depended on the gas temperature and the time of staying, usually d by the particle diameter that grinding machine 16 is ground to requirement 90Be about 20-100 μ m) and by means of the jet pipe of carrying air 17 via reactant feed lines 18 input feeders 6.Two feeders 4 and 6 converge at the section starts near exhaust steam passage 2.The additive capacity that is metered into is replaced adsorbent and the reactant that enters the consumption of residue hopper 11 by the residue outlet.Perhaps, can reactant be introduced in the exhaust steam passage by transmission channel 29 and feeding line 12 with adsorbent.
Adsorbent and reactant are sprayed into adverse current or cross-flow with high relative velocity.Here, exhaust gas velocity is about 15-25m/s, and jet velocity is 15-50m/s, and therefore the relative velocity that reaches in upstream injection is 30-75m/s, particularly 40-60m/s, or the relative velocity that reaches in cross-flow is sprayed is greater than 15m/s.Because described higher relative velocity, counter-current has the technology advantage with respect to the cross-flow method.
Perhaps, adsorbent and/or reactant can be imported feeding lines 27 and also can together pass through thus by transmission channel 30 and 31 and introduce in the exhaust steam passages 2 near the feeder 5 of fabric filter 3 with recycled materials.
In this embodiment, adsorbent is that bulk density is about 0.55g/cm 3, particle diameter distribution d 90Dried open-hearth furnace coke (HOK) for about 50 μ m.
In this embodiment, reactant is that bulk density is about 1.0-1.2g/cm 3, particle diameter distribution d 90Dried NaHCO for about 20-100 μ m 3In experiment, can demonstrate the dependence of lapping degree to conversion rate and gas temperature.
Fig. 2 and 3 has shown NaHCO 3Aerial conversion.Transverse axis in minute time t, the longitudinal axis is NaHCO 3The percentage that reduces from initial mass of quality.When quality reduces 37%, NaHCO 3Be reformed completely into Na 2CO 3This value is plotted in 37% place by the horizontal line of overstriking.
Fig. 2 has shown at 150 ℃ EGT and the particle diameter d of about 50mm with chain-dotted line 90The time NaHCO 3Conversion, shown particle diameter d with dotted line at 130 ℃ and about 35mm 90The time NaHCO 3Conversion, shown particle diameter d with solid line at 110 ℃ and about 20mm 90The time NaHCO 3Conversion.
In Fig. 3, all keep particle diameter identical for all temperature, both d 90Approximate 35mm.For 150 ℃ temperature, full out realized fully transforming, for other temperature,, the reduction of temperature increases along with transforming the required time fully.
Lapping degree is thin more, transforms carry out fast more.Because the time of staying is long, for reaching identical utilization rate (stoichiometry) NaHCO 3Also needn't grind too carefully.In the time of suitably, because NaHCO 3Material properties, it must be right after being incorporated into and describedly grind before in gas stream.
Generally speaking, as long as suitable long residence time is provided, method of the present invention also can be carried out being low to moderate under the EGT of 60 ℃, 70 ℃ or 80 ℃ certainly.
In the following horizontal section of the exhaust steam passage 2 in Fig. 1, recycled materials is introduced waste gas stream on direction opposite with the waste gas flow path direction or crosscut with it by feeder 5., reached the relative velocity of 30-75m/s, particularly 40-60m/s equally for upstream injection here, or introduced the relative velocity that has reached greater than 15m/s for cross-flow.
Waste gas enters fabric filter 3 then.The major function of fabric filter is to isolate the solid matter of carrying with waste gas.They are made of reactant, adsorbent and the recirculation residue of sintering breeze, product, not consumption.
For making very thin dust composition and organic exhaust gas component not penetrate actual filter cloth, to pile up there and pressure is fallen very promptly raise (depth-type filtration-cause the saturated of filter bag), filter cloth advantageously is furnished with pore plastic foil or coating or is soaked into.Its effect is to make dust granules gather and form filter cake from the teeth outwards, and filter cake then plays actual filtration (=surface filtration).
Used filter fabric is for example, to have the glass fabric of PTFE (polytetrafluoroethylene (PTFE)) coating or the aromatic polyamides with PTFE coating.
Because the moisture in the sintered discharge gas and contingent dewfall, crucial process equipment parts are heat insulation and are followed heating if necessary in the dust of deposition.
For guarantee for the first time with promptly had a certain this type of aided filter layer before waste gas contact, can be on fabric filter 3 the precoating auxiliary agent, for example, be with the quick lime/carbon mix of additive, it is for example with trade name
Figure A200780007085D00101
Known.This layer can also and prevent to destroy filter cloth thus in conjunction with the moisture content that condenses in the starting process from waste gas.Can be provided for introducing the device of precoating, but not show in the drawings with material.
Used fabric filter 3 mainly is made of the filter shell 21 of band filter bag, thick gas compartment 22, hopper 23 and clean gas chamber 24.
The waste gas that is loaded with dust enters thick gas compartment 22 by thick gas access passage.Gas velocity is lowered thus, and dust granules is evenly distributed on the gas distributor wall 25.Gas passage stopped by top board (bag the end), thereby all air-flow all can only pass filter bag and enters clean gas pipeline 15 towards chimney via clean gas valve and clean gas chamber 24.
Dust remains adhered on the filter bag that flows into from the outside, and forms filter cake.This produces actual filter effect.Along with the rising of the dust-loaded amount of filter bag, the filtration resistance that need overcome also continues to increase.For holding it in economic level, must clean filter medium often.This realizes by means of purging system.Enter by pre-control valve from the compressed air 28 of compressed air distributing pipe and to attach troops to a unit in the blowpipe of every group of bag, thereby each bag is cleaned equably.The dust layer that adheres to is blown out by the pulse of compressed air of strengthening by extra Venturi tube injector weak point, regular basically.Venturi nozzle and blowpipe nozzle are used to optimize the compressed air demand.Interior support basket keeps the shape of filter bag.In the cleaning process of filter bag, the dust between the filter bag falls into hopper 23 and is removed continuously by spout member therefrom.Vibrator on the bucket wall can promote the discharge of dust.
Part dust is removed and is transported to residue hopper 11.Major part is recycled in the exhaust steam passage 2.The recycled materials of discharging from fabric filter 3 by means of mechanical moving device is utilized transmitting device by metering system 26 input recycled materials feeding lines 27, and is introduced exhaust steam passage 2 by feeder 5.Recycled materials can be blown into (adverse current or cross-flow), or also can utilize gravimetric and, in case of necessity, be distributed in the air-flow by means of the static mixing parts.Guaranteed constant material flow by metering system 26.
Recycled materials is that (moisture＜1% weight) and the bulk density done are about 0.4-0.5g/cm 3, particle diameter distribution d 90Be about 10-50 μ m.
By recirculation, in the residue the still available part of unreacted reactant and only a little the adsorbent of load also enter once more the circulation and fabric filter 3.This has reduced reactant consumption or has caused by adsorbing the remarkable improvement of the pollutant deposition that produces by the absorbent concentration that improves in the waste gas.
Yet the recirculation of fabric filter dust has also caused the deposition of the improvement of fine dust on fabric filter 3.The sub-micro fine dust particles is condensed.Therefore, the average grain diameter of the particle that separate increases.
In the method, the deposition of pollutant is carried out as described below: NaHCO 3, after thermal activation and the adsorbent of any existence in the hole, absorb organic component and heavy metal.Acidic components when deposition, reactant with fly to flow in these component partial reactions.Residue is deposited on to flow through in the filter cake process and takes place.
If make waste gas and NaHCO 3Contact, then acid waste gas component S O 2, SO 3, HCl and HF reactant (after the thermal activation) chemically reactive and form dried solid therewith as product.These solids are removed in waste gas stream in fabric filter 3 subsequently.
Separate performance in order to reach desirable acidic components, must metered reagent.
The heavy metal (being mainly Hg, Cd) that exists in organic component (dioxin, furans, VOC, PAC) and the waste gas is deposited by fettering through being adsorbed property of absorption ground in being diffused into hole path afterwards.Soda that forms after the thermal activation and for example used open-hearth furnace coke (HOK) have great void content, and these harmful constituents can be strapped in granule interior.Can also strengthen absorption by the chemical process in the pore of HOK; For example, still be present in SO in the waste gas 2Be converted to sulfuric acid or sulfurous acid to a certain extent, then heavy metal (metal Hg) and they reactions.
Heavy metal enters in sintering or the pelletizing equipment waste gas by raw material (ore and additive) and recycled materials (dust).For example, the metering by conditioned reaction thing and/or adsorbent can prevent to discharge peak or super row.
The residue (dust/incrustation) that organic compound (VOC=volatile organic matter, and PAC=polynuclear aromatic compound) derives from those reducing agent compounds without completing combustion in the employed reducing agent that is present in the sintered mixture, burner (igniter, gas heat etc.) again or uses.Condensable organic part in this admixture of gas may condense on the filtering material of fabric filter 3/and interior and cause irreversible destruction (gas permeability reduces, increase falls in unit pressure to filtering material, Xiang Guan gas throughput still less, or more frequent cleaning process therewith or the like).The result is the lifetime of filtering material and running cost rising thus.
Unfavorable for eliminating these, periodic measurement concentration of condensable organic component in the air-flow before or after introducing adsorbent targetedly.Therefore, can regulate required quantity of sorbent adapting to above-mentioned load, the adsorbent that promptly needs (fresh or from recycled materials) amount wants to make that condensable organic part is bound on the adsorbent basically under operating condition.Can improve the life-span of filtering material thus greatly.
For this reason, advantageously providing can be independently of one another, particularly as thick waste gas and/or through the function of the characteristic of purified waste gas (thick and clean gas) recycled materials amount and fresh additive capacity are regulated.The characteristic of waste gas may comprise the content of temperature and all contaminations.
According to the difference of pollutant, other mechanism of possible adsorption process is also extremely important.These depend on the physicochemical characteristics of component, for example molecular diameter.Therefore, sorbent usedly also should suitably be regulated (distribution of pore/channel diameter).
For fear of the temperature peak that occurs in the operation of unstable state sintering or pelletizing and may damage filtration fabrics or miscellaneous equipment parts, provide the emergent sprayer 19 of water in exhaust steam passage 2 inside.This makes the maximum inlet temperature is limited in 160-180 ℃.
In the embodiment shown in the figures, the SO of dry form 2Thick gas concentration average out to 600mg/Nm 3600000 Nm 3The sintered discharge gas stream of/h is desulfurized to less than 100mg/Nm 3In addition, also will separate 20mg/Nm 3HCl.The dust content of described waste gas is 100mg/Nm 3, pure dust content is 5mg/Nm 3In order to meet the heavy metal limit value, used the open-hearth furnace coke of 30kg/h.Desulfurization is by using 850kg/h just to be ground to the d of 30 μ m before spraying 90NaHCO 3Realize.Adsorbent and reactant are introduced respectively.Adsorbent is introduced with the relative velocity of about 50m/s with adverse current, and NaHCO 3Introduce with the relative velocity of 20m/s with cross-flow.For adsorbent provides 7 jet pipes, for reactant provides 4 jet pipes.The time of staying of additive in air-flow (flying stream) is 2 seconds.Recycled materials is counted the weight adding by means of auger conveyor and is dispersed in the air-flow by means of static mixer after additive.
The reactant useful load is about 1400mg/Nm thus 3, the adsorbent useful load is about 50mg/Nm 3Thereby, make the adsorbent of interpolation and reaction-ure mixture until 1450mg/Nm 3Scope in.The amount of recycled materials is 10t/h (～16.7g/Nm 3), be about 12 times that adsorbent adds reaction volume therefore.NaHCO 3Stoichiometry be 1.05.The residue amount that produces is about 800kg, and wherein moisture is 0.5%.
Approximately cleaned the once filter cake of every group of bag in per 80 minutes.The sintering gas temperature is not less than 110 ℃ and also is no more than 130 ℃, average 120 ℃.50m is being installed 3The basis of recycled materials buffer container on, bulk density is 500kg/m 3, the calculated value of mean residence time is about 27 hours, additive is used hot waste gas to handle about 10 hours (NaHCO therein 3The maximum conversion time).
The mark tabulation:
1 waste gas
2 exhaust steam passages
3 fabric filters
4 fresh adsorbent feeders
5 recycled materials feeders
6 fresh reactant thing feeders
7 reactant hoppers
8 adsorbent hoppers
9 reactant measuring containers
10 adsorbent measuring containers
11 residue hoppers
12 adsorbent feeding lines
13 carry air
14 carrier air blasts
15 lead to the clean gas pipeline of chimney
16 grinding machines
17 carry air
18 reactant feed lines
19 emergent sprayers
20 -
21 filter shells
22 thick gas compartments
23 hoppers
Clean gas chambers 24
25 gas distributor walls
26 recycled materials measuring containers
27 recycled materials feeding lines
28 compressed air
The alternative transfer passage of 29 reactants
The alternative transfer passage of 30 adsorbents
The alternative transfer passage of 31 reactants

Claims (18)

1. handle method from the waste gas of sintering and pelletizing equipment, wherein dried additive is in fabric filter (3) upstream is added to waste gas from sintering or pelletizing equipment, particularly add in the exhaust steam passage (2), and described additive is separated from waste gas by described fabric filter (3) subsequently, is characterised in that described additive contains sodium acid carbonate NaHCO 3As reactant and at least in part in fabric filter (3) upstream is recycled waste gas stream, particularly be recycled in the exhaust steam passage (2).
2. the method for claim 1, the temperature that is characterised in that described waste gas is less than 140 ℃, particularly less than 130 ℃.
3. claim 1 or 2 method, the temperature that is characterised in that described waste gas is greater than 60 ℃, particularly greater than 90 ℃.
4. any one method among the claim 1-3 is characterised in that in the zone of described fabric filter upstream to be designed to fly to flow reaction zone.
5. any one method among the claim 1-4 is characterised in that the mean residence time of the reactant of new input surpasses two hours, particularly above one day.
6. any one method among the claim 1-5 is characterised in that described reactant feeds intake with the coarse granule form and just was ground to the fineness of requirement soon before using.
7. any one method among the claim 1-6 is characterised in that described additive rests on described fabric filter (3) more than last half an hour as filter cake.
8. any one method among the claim 1-7, be characterised in that described additive at least one position (4,5,6) go up the anti-phase introducing that flows to described waste gas.
9. any one method among the claim 1-8, be characterised in that described additive at least one position (4,5,6) go up with the traversed by that flows to of described waste gas and introduce.
10. claim 8 and/or 9 method are characterised in that described additive introducing in the described waste gas with the relative velocity of 15m/s at least with the relative velocity of 30m/s at least with under the situation that cross-flow is introduced under the situation that adverse current is introduced.
11. any one method among the claim 1-10 is characterised in that described additive introduces in a plurality of positions that are distributed on this cross section at least in a certain cross section of exhaust steam passage (2).
12. any one method among the claim 1-11 is characterised in that described additive locating to introduce in a plurality of positions (4,5,6) that flow to along waste gas.
13. any one method among the claim 1-12 is characterised in that described additive introduces by at least one jet pipe.
14. any one method among the claim 1-13 is characterised in that described additive and described reactant introduce together.
15. any one method among the claim 1-14 is characterised in that recycled materials on the one hand and fresh reactant thing on the other hand and the fresh adsorbent that may need introduce at diverse location (4,5,6).
16. the method for claim 15 is characterised in that adsorbent and/or reactant introduced before recycled materials.
17. any one method among the claim 1-16 is characterised in that reactant is as acidic components content (SO for example 2Concentration) and/or the function of the content of condensable organic compound and/or heavy metal introduce.
18. any one method among the claim 1-17 is characterised in that adsorbent introduces as the function of the content of the content of condensable organic compound and/or heavy metal.
CN2007800070854A 2006-02-28 2007-02-19 Process for the treatment of offgas from sintering and pelletizing plants Active CN101394915B (en)

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AT0034006A AT502375B1 (en) 2006-02-28 2006-02-28 Treatment of waste gases from iron ore sintering and pelleting plant comprises adding sodium bicarbonate to gas in feed pipe upstream from fabric filter which then separates it out, at least some bicarbonate being recirculated to feed pipe
ATA340/2006 2006-02-28
PCT/EP2007/001396 WO2007098867A1 (en) 2006-02-28 2007-02-19 Process for the treatment of offgas from sintering and pelletizing plants

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CN103879970A (en) * 2014-03-14 2014-06-25 成都华西堂投资有限公司 Production process for preparing sulfur by recovering sulfur dioxide from flue gas
CN109499295A (en) * 2018-12-29 2019-03-22 米凯利科技（北京）有限公司 Dry method desulfuration system

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CN103879970A (en) * 2014-03-14 2014-06-25 成都华西堂投资有限公司 Production process for preparing sulfur by recovering sulfur dioxide from flue gas
CN103879970B (en) * 2014-03-14 2015-09-30 成都华西堂投资有限公司 A kind ofly from flue gas, reclaim the production technique that sulfurous gas produces sulphur
CN109499295A (en) * 2018-12-29 2019-03-22 米凯利科技（北京）有限公司 Dry method desulfuration system

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UA59847U (en) 2011-06-10
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TWI438283B (en) 2014-05-21
RU2008138582A (en) 2010-04-10

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