DE1551878A1 - Process for reducing air pollution from combustion products - Google Patents

Description

Bfc $ 16 / .CE 2813

kö / ko

Applicant: Combustion infcineeringp Inc. Windsor ^ Connecticut ₈ UoSoA ₀

Process for reducing air pollution through combustion prod ukt e

The invention relates to a method and devices for Control of air pollution from incinerators and, in particular, a technique for removing the sulfur components and dust particles from combustion products or smoke » gassing a steam generating or similar device «where = · when the flue gases are heated before they enter the atmosphere will"

In recent years, air pollution has become a major problem and it is a long time; Effort and costs of economic in the development of systems for Iiedu ° "this impurity zierunt 'Investments wordene One of the many sources of air pollution are the flue gases of combustion plants ^ such" B ₀ generating steam units "· The sulfur oxides SO and SO are as luftvergiftende Bastand parts of such flue gases are of essential importance o The solid particles? such as Z ₀ Bo fly ash and other dust particles also contribute to the pollution problem ₀ if they have not been completely removed uneconomical

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The present invention proposes a Rauchgasreinigungfl plant from _f in which the wafer-gas to remove the impurities naee β β wash ν ground, the flue gases are saturated by the wet scrubber at a relatively low temperature and in the substantial Ausmasβ with Vaeaerdampf therefore, the present invention proposes, reheat the flue gases after wet cleaning? in order to increase the temperature of the gases vented from the chimney, thus avoiding an undesirable visible cloud of steam and local pollution due to the low temperature? if gases with insufficient buoyancy are discharged from the nasal cleaner. The present invention further proposes a plant before _r in which an additive in the flue gases for reaction with the sulfur components is introduced and in which the wet cleaner supports Keaktion and the reaction products and other Pestteilchen from the flue gas flow away.

Ke is an object of the invention], a technique for the economical removal of air pollutants from the flue gases to remove a combustion process *

A particular object of the invention is ₅ to provide a method and apparatus in which ^ brought Scliwefelbestandtello and other acid components to react and are removed while dust particles from the flue gases are removed and at Oenen continue the flue gases prior to their

Fume hood can be reheated through the chimney.

Another task is esj. a method and apparatus for To create wet cleaning of the flue gases from incineration plants / and to provide a technique for reheating the wet-cleaned gases.

The invention achieves these objects by a method of reduction air pollution from combustion products,

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41 · when burning a hot air-fuel mixture from a combustion plant? at cien a certain amount of air is heated; a first part of this heated t uft to the incineration plant. Formation of the mixture is fed, in which the combustion products are washed wet with a rust liquid after leaving the plant? in which a large portion of heated air is supplied to the washed products of combustion and in which the mixture of hot air and products of combustion is discharged into the atmosphere.

Invention also provides a device for reducing air pollution by the Verbrennungeprodukte _t the hot when a Verbrennunc. Air-fuel mixture to a combustion chamber Verbrennungftanlage escape ^ mi.t ;, in which the air-fuel mixture is venrannt and "with an air preheater _f with air supply _members; connected to the Juft preheater? which is connected by first Lel ^ tungsglleder with the interior of the combustion chamber and _f with conduits leading from the outlet of the combustion chamber in a Naeereiniger "from which an outlet duct leads to a rabbit and second Leitungnglledern? which connect the air supply elements to the outlet line at a point between the water inlet and the chimney

For a better understanding, the finding is now described with reference to the accompanying drawing. In the drawing the invention in connection is illustrated old a steam generating unit 10 "The Danpf generating unit includes a combustor 12p a horizontal gas conveyance I ^ and a rear gas guide l6o The Brennkaemerteil l ;: contains a plurality of burners 18 _r comprises a mixture of Feed pulverized coal and primary combustion _{air into the combustion chamber e} Secondary combustion air is fed into the combustion chamber through the wind boxes ZO. The combustion products rise in the combustion chamber and reach the horizontal gas _{duct 1 ^ 1} where they exchange heat with the Kndüberhitzer 22: the post- superheater ρΛ etehea. Then the combustion products or

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in «Me Ι ** π. * · Γβ G * e * ttiurtmf 10 and stand» » Jfcnts & t ntf.t d. «Ro. ¥ ori6be> rh.i. * «« Mr 26 and put them in the L «ifcw» ß J (J

Here the Br »n» Jcejm »* r is given over a 5 * ti IH se 32 eufjeiTüb.rt. In part of the air also 3 ^; i * i.Tpt abffczeeen and the L # iti "£ 36 elneeepelate In the Pulrermühle 38 In dl · Pulvermuhle is the same carbon · ko a FHrderer and introduced a · Sol · Uz, Dl · · I'ulvernilhl, by the same type one can? as he iet described in US PatentBclirift 2848 I70, the coal pulverized · and never nothin 'with the prlnären combustion air from line 360 This mixture of pulverized coal and primary combustion air via the line h6 kh to entrance of the aspirator out by the suction fan kk is the coal-air "Minchung via line kti the burners 18 fed" the remaining · combustion air of the air blower 32 strftmt by the conventional air preheater 50 and then through line 51 to the Wlndkästen 2U ₀ where eintrltto from never in the combustion chamber of the air preheater 5 ^Ü serves "the breath gases in line 30 Warm · withdraw and transfer them to dl" secondary combustion air in the line 50 to transmit. US Pat. No. 2,911,202 presents one type of air preheater that can be used.

Diethylene most Brenne offe contain certain Schwefelmeng "n _p although coal is normally a lower proportion al · oil or

° as contains · During the combustion, these sulfur constituents are converted into SO and SU «In addition, the combustion process naturally generates large amounts of water vapor. The presence of these sulfur constituents and the water vapor in the combustion products can cause serious corrosion problems on high-temperature heating surfaces "such as Z ₀ B" in the preheater and end heaters 26 and 22 and the post-heater 24 *, but also on low-pressure heating surfaces such as Z ₀ B.

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the economizer 28 and the Lui't »preheater 5 <><> It is believed _p that the corrosion of Hochtertperaturheizrlächen is primarily caused by the formation of Komplexeulfaten ;.

acid while dl · corrosion on the Niedertemperaturheizflächen primarily through the formation and! Condensations of sulfur "is caused to be _o For this corrosion of the low is avoided" temperaturheizflachen ,, must Gastenperatur maintained above the dew point of the acid ;, in which case all or essentially all of the sulfur components in the flue gases are fed into the chimney and removed from it together with the solid particles «

One aspect of the present invention consists in the addition of additives to the liauchgasstrumungj, which react with the SO and SO in the flue gases to form harmless materials? the slightly auη the gas flow removed _ö can this, editable additions made in such materials? such as oxydes ρ ilydroxyden and carbonates of the alkali and alkaline earth metals ”, so that an“ economical desulphurisation system is created. It is necessary that the material used is cheap and can be handled as possible so economically "That's why there are the most for the Kr, = finüung suitable materials from unsorted limestone or dolomite ο do h" are without specification of your chemical to "saimnens et tongue these materials are relatively cheap compared with others in the group in question coming materials "Then finely pulverized limestone or dolomite as a broken is more expensive _c has to be the most Vorteilhaftesten these materials herauf.gestei.lto into the powder mill 38 together with the coal feed "Dw limestone otter dolomite is then pulverized together in the l'ulverraühle with the coal and fed into the burner 18 along with the pulverized coal and the primary combustion air, this arrangement is also advantageous _c since it is necessary _ff that the carbonates prior to their Introduction to the wet cleaner 52 to oxides en ,, as will be explained in detail later * Da · Does burning take place in the combustion chamber 12?

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where the heat _{drives the CO 2 out of} the dolomite or limestone o With this arrangement it is not necessary to buy burnt or pulverized limestone or dolomite? Instead, the powder beam only needs to be enlarged a little to accommodate deodorant material. Of course, pre-powdered and pre-burned additive can be used ^ but presumably with increased accounts.

The burnt dolomite, CaO χ MgO _1, which was produced in the combustion chamber iet _P reacts with the sulfur _{components SO 2} and SO to form waste products such as CaSO ^ ₁ , CaSO _f MgSO ^ and MfSO j, while the burnt limestone ^ CaO to products such as CaSO. or CaS ^ reacted These reactions take few tens • place in limited Ausease ,, while the flue gases flow through the steam generating unit and result in a reduction of the corrosion on the heating surfaces in the unit _o The reduction of corrosion to at least the llochtenpe- = raturheizflachen in coal-fired units is thought by the deposition of a portion of the additives causes "which allow the formation of corrosive complex sulfates does not allow," Ee, however, has proven to _f that about 5 ° $> of sulfur compounds in the flue gases before discharge from the steam generating unit have reacted with the dolomite «Therefore a considerable proportion of the SO and probably some of the SO_ _p that probably reacts first _{3 is} retained and could be discharged into the atmosphere together with the flue gases.

The present invention therefore proposes the additional use of a wet cleaner 52 or a gas scrubber 52? which is connected between the steam generating unit 10 and the chimney 53 for wet scrubbing of the flue gases o The nose cleaner does not only remove the sulphate and sulphite particles? which de in the steam generator by the reaction "burned dolomite or limestone · have formed with the Schwefelbestandteilchen" but also causes additional reaction

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the additives with the sulfur constituents so that a substantial part of the sulfur constituents are removed from the oil immersion organs? For about $ 98 or $ 99, " The burnt additives are in the vase of the wet cleaning agent, while the unfired" oil or limestone is relatively insoluble. For this reason the burning is necessary and. it is also necessary »that it takes place before the wet cleaner; Since the first reactions in the nasal cleaner in the liquid phase β did tf inctene The SO and SO. are only slightly soluble in water and therefore react quickly with the dissolved additives, so that the concentration of £ 0 and FO in water is practically zero. The reaction products are all relatively insoluble with the exception of MgSO. and therefore they are quickly ausgefälltο from the ventilation Dt wet cleaner removes ausserdera other solid particles from the Kauchgasetromungp such _o u, the fly ash and the reaction * inert components of the additives ,, This Staubeaeralung can be effective to 98 Ik and therefore electrostatic dust collector are not necessary .. So the Naasreiniger 52 is not only used to remove solid particles from the gas flow? but also to promote the desired reactions · »

The nose cleaner 52 may be any of the many available on the market types * Two commercially available wet cleaning which would be sufficient _r are the Peabody gas Skrubbero the t'eabody Engineering Corporation of New York City and the Floating Bed Skr * ubber the Aerotec Industries ,, Inc ° _t of Greenwich ^ Connecticut. The scrubber operates continuously and the ausfliessemte from Him liquid is fed into a settling tank Hk The reaction products consist vrrhältnismüssig rapidly in the settling tank, and the sludge is removed via line 56 ₀ The About your mud standing ι carcasses will be at the top of the settling tank via the Line 58 withdrawn by a pump 60 and again through the

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Wet cleaner 52 circulated. The fresh water is fed into the system via line 62 . Considerable water · »■ can additionally su those for the. Desulfurization be required ₁₁ so that the ttassreini & does not clogged · The wet-purified gases are _o fed from the scrubber via line 6k of the fireplace 53 exiting from the wet scrubber scrubbed gases are located on verhHltnismässig low temperature ₀ such "B. on ky ^a C (12 "° F) and are these gases saturated with water if these gases would nbjp through the canteen at this low temperature? a visible volto of water would normally be generated & ussern ₉ of the small at the remaining percentage of SO ₂ and SO in ü * n flue gases local contamination and corrosion problems' cause could "order for this local precipitation is avoided and-rising flue gases to a substantially crosseren height, they are after leaving the Mass cleaner heated to about 77 ° C (170 ° F) "so that the draft of the chimney increases and d The relative humidity is reduced. According to the present invention, this heating occurs as a result of this? that a part of the preheated air from the line 51 withdrawn via line 66 and introduced into the line 6h _p in αer are the washed Kauchgase · Because this air has been heated clean and only be _t in this way, the cleaned flue gases no impurities added. All possible temperatures are listed below!

Air entering the air preheater 27 ° C (80 ° F) Air exiting the air heater 299 ° C (570 ⁰ F) Flue gas entering the air preheater 366 ° C (69O ⁰ F)

Flue gas as it emerges from the air preheater 190 ^o C (248 ° F)

Flue gas when exiting the wet

cleaner '49 ⁰ C (12O ⁰ F)

Flue gas as it emerges from the breath "

Gaenach heater 77 ° C (170 ° f

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The post-heating of the flue gas * by 28 ° C (5 °° Ρ) _s as in the above example would require an amount of preheated air ^ which is about 11% of the Raiiishgaemenge _c the flowed out of the wet cleaner This pre-reserved air is in the line 6k introduced _c in an enlarged part or in the chamber 67ο the line 66 for the preheated air enters the chamber 67 tangentially? so that a whirling motion is generated to promote the mixture _o Various forms of mixing devices can be used ^ such as z «IJ. fixed blades in the path of the gas flow? which create a vortex «movement and mixing« »On the other hand, a specially created mixture does not necessarily have to be necessary« This naturally depends on the dimensions of the existing turbulence and the distance to the point of introduction into the chimney

The fact? that part runs the preheated 1 _f from the air preheater flows ₉ is removed and not in the combustion chamber fed w ± rd _{P p} that more air through the VorerJiitzer flow rough _c means that a sufficient amount of both the combustion and for the subsequent heating of the flue gases is available "This means as-deruraj that the air when flowing out of the preheater to be at a lower temperature · = is _t when they would normally _r Z ₀ B" by 17 ° C (3O ⁰ f) colder IATO This the output of the boiler is somewhat reduced _p which has to be compensated for by feeding in additional fuelα This reduced boiler flow is overcompensated by other cost savings, which the proposed system for post-heating with direct contact has compared to other possible systems. "Post-heating" systems with indirect contact all require the arrangement of heat condensation surfaces in the flow of the combustion gas s · after wet cleaning This is Hussert course considerable capital costs and an expensive pressure loss _o When using such Kärmeaustauscher _p particularly when a complementary Wünseau is · tau · more installed before the wet cleaner ,,

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withdrawing the heat for reheating to this point, there is the problem of Verstorbne diener Värraeaubtaiischer ₉ This problem does not occur in the present invention, of course, on _c Additional trepamli-se in the cost of the chimney by the present invention thereby possible ;; that it can be built lower, and because of the reduction in pollution He. and corrosive materials can be lined with steel instead of concrete «

The temperature and the amount of from Naesreiniger from "flowing flue gases will änuern course, under certain conditions, such as Z ₀ B ₀ is at a change of power of Dampferzeugersο Therefore varlieren required for Mach-heating of the flue gases amount of preheater air _o are Devices for regulating the post-heated air before ^ esehen _c such as z ₀ B ₀ the temperature measuring device 68 _ς a common thermocouple that regulates the folding © 7 ° in the line 66. Dio control is done with the help of suitable conventional control devices 72 ο

The entrained in the flue 53 Wasaermenge can werdenp reduced by dans the washing drums wirci maintained at a relatively low temperature _f so that the flue gases to the scrubber with little temperature abandoned This äusaert located in a lower proportion of water vapor in the gases prior to the post "heating ^ so that the dew point of the gases leaving the chimney is lowered o If there is insufficient cooling of the washing water in the settling tank or due to the addition of fresh water, a heat exchanger 7 can be used for cooling in the washing water circuit to generate the required cooling _o

The use of a variety of Naesreinlgern can _c necessary _WQ rden namely _ö due to the large amounts of gas, the generation of large steam units emanate "This can easily happen as a result? that the flue gas trim after exit

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The air pre-heater is subdivided and then either brought together again after the Naaareinlgern and discharged through a single chimney or discharged through different chimneys. that just as the present Krfindung on SI or gas-fired units can be applied to coal-fired units such as ₀ Just one abgelindert ·· system is necessary "to feed the additives into the combustion chamber, this can easily through the encryption * application separate Pulverraühlen and Elnapeisevorrichtungen happen _P what can also be done with coal-fired units ο

Although a preferred AuefUhrungsbclspiel the invention has been illustrated _p it will be understood SLCH _c that this is just the Ver ~ anschaullchung served and no limitation is and that changes in the design ,, eggs Kombinution and arrangement of parts and steps can be made könnenρ without departing from the area of Invention to be sealed o

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Claims (1)

Claims le) A method sur reduction of air pollution by DLFC combustion product ", the fuel-mixture air-strrimen during the combustion of a hot a Verbrennungfcanlage * characterized geke nnzeich net, as it / a certain amount of air heated _s / a first part of this heated air of combustion * system for the formation of the mixture supplied to wire »! da · β the Combustion products after leaving the plant a washing liquid nasal washed ^ that a second part of the heated air is supplied to the washed combustion products / and that anachilessend the mixture from hot air and products of combustion into the atmosphere led away virdo 2 «) Method according to claim 1« characterized * that the Temperature of the second part of the heated air greater than which is the "product" of the wet-washed incineration Jc) Method according to claim I _9, characterized in that the amount of air is heated by heat exchange with the combustion products α ho) apparatus for performing the method according to claims l _r 2, or 3 in which the air-fuel mixture is burned with a combustion chamber * and rerhitzer with an air-V © "characterized in that air-supply elements _p (32>' Jk) . the air preheater (5U) are connected »the first) line members (51)« it is connected to the item inside the BrennlrwsMisr (I2) , and that Lsltuneen (3 ") _ψ ^ -Z *** ^ ** * '^ kaankir (12 « Ik ₁ 16) into an» asereinieer «reads an outlet line (6h) HtI ·· chimney« wide line smooth leather {66) the the outlet pipe {% h \ axt * l »connect ewi cleaner and the chimney OO9S30 / Ö305 bad ^ · 5) Device according to claim ₉ k j characterized in that the second INTR are _o Egli Eder (6 <5) downstream "from the air preheater to the air supply members connected the ₀ 6 "/ device according to claim 4 or 5p characterized _p dans lines between the combustion chamber and the output Aasereiniger through the guide air-preheater, so that at least part of the heat of eih Verbrennungeprodukte au.f the air transmitting wirdα 7 «J Device according to claim h ₉ 5 or 6 _P characterized in that downstream of the point of introduction of air in the outlet line (64) temperature sensors (68) are arranged and that cone members (7 ° p72) dependent on them for control the amount of air mixed with the combustion products is provided; so that the temperature within certain limits maintained wlrd _o 8o) Device according to any one of claims k ~ 7β characterized «· characterized by devices for.Introduction of additives _: in the flow of combustion» productsο 9o ) Device according to any one of claims 4 "= 8 _0, characterized by a cooler (74) in the circuit of the washing liquid" so that it is cooled down , ι • V *. ¹ ACf Lee r s side