DD266973A1 - PROCESS FOR COMPLETE DRY GAS CLEANING - Google Patents

Abstract

The invention relates to a method for a comprehensive, dry gas cleaning. For dry gas cleaning with the elimination of dust and / or gaseous pollutants staggered granule filter layers are used. The sorbent consists of alkaline earth-containing raw materials or substances. It is used repeatedly under activation and build-up granulation. The process can be used in all heat generating systems, such as steam and hot water production systems, in the coal refinement beyond also in fire gas dryer plants.

Description

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Title of the invention

Procedure for a comprehensive, dry gas cleaning

field of use

The invention relates to a method au a comprehensive, trookenen gas cleaning with binding dust, aerosol, vapor and gaseous pollutants from useful or exhaust gases, in the combustion, Sohwelung or gasification solid, liquid and / or gaseous fuel and / or combustible substances are produced by means of sorblerender, porous, predominantly erdalkallhaltlger raw materials and / or substances In the form of filter elements in a modifiable Wanderoder SohütteohichtflltGrsystem "The procedure can in heat generating plants, like steam ₉ hot water, hot gas generators but also in Abstoffverbrennungs, Kohleveredlungis- or Trooknungsanlagen be integrated with the most extensive use of heat ·

Characteristic of the known teohnisoh «. α solutions

For the separation of dust and / or gaseous pollutants from Rauoh and exhaust gases, a multitude of very low-boiling processes is already used · A more detailed analysis showed that these processes are used almost exclusively behind heat generation plants operated with hard coal or fuel oil.

The (total method of exhaust gas purification is characterized by the fact that a separate reactor has to be installed almost for each pollutant component.

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Thus, for flue gas dedusting predominantly electrostatic precipitators, for the separation of hydrogen halides Wasserwäsoher, for desulfurization lime / Kalketeinwösoher ,, Denitriefizierung reduction catalysts or with carbonaceous sorbents filled reactors used for Sohwermetalloxidentfernung wet tissue filter.

The initial investment in space, energy and space required by fuel oil or coal fired heat generators has almost doubled due to the incorporation of this extensive gas cleaning technology · The main problem is that some of the resulting residues, such as calcium, halogen compounds, heavy metal compounds, the soluble nitrite / nitrate compounds as well as the effluent have to be treated due to their toxicity and / or instability, converted into beneficial substances or deposited on special precipitates. »

By contrast, much less successful efforts to process developments for heat generation systems in which ballastreiohe, niederkalorisohe fuels and / or substances such as lignite, garbage etc are used, remained "When cleaning flue gases from such fuels at the same Nutawarmeleistung the heat generation plants approximately twice as large amounts of exhaust gas are treated, from which, due to the usually approximately equal pollutant content, the three- to five-fold amount of soad must be removed. In addition, the gas purifying plants have to be designed to have 80 deg higher exhaust gas inlet temperatures. These facts are the reason that the gas purification costs when using low calorific fuels are several times higher than those with the use of high caloric fuels.

The low-cost, low-calorie, low-calorie fuels are based on the principle of dry cleaning. The aim is to use the heat generators and the flue gas channel as reaction spaces for pollutant capture. "DD-OS 142 * 083; DD-OS 154 * 307 · Low-priced, mostly dust-like alkaline earth compounds in carbonate, hydrate or oxime form are used as sorbents. These sorbents, summarily referred to as additives, are brewed both in the high temperature range and in the low temperature range of the crude gases. You walk in the same direction with the roughness gas and almost equally as well as this in a maximum of 10 seconds the entire system ·

The binding of pollutants occurs almost exclusively on the surface (heterogeneous topoohemiotic binding mode). As a result, the material turnover rates are small. In spite of optimization measures, only conversion rates are currently around 30 i reached 5 % at stoichiometry-sized additive addition level.

This results in efforts to increase the material conversion rates, in part by increasing the Pelnteiligkeit of the additives, by adding re ~ action-demanding substances, on the other hand by a circulation procedure. DD-OS 218,563; DD-OS 223,073; DD-OS 216.388. These efforts have so far failed greater successes. Thus, for example, in the case of circulatory catfish of additives after an intermediate activation with extinguishment of the incinerator cell, only turnover rates of 40 lbs. 5 were reached. In view of the high transport costs, an increase in sales per annum of 10 l % never satisfies.

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A negative experience fact was the recognition that with a recirculation of the Additlv-Asohe the dedusting conditions are substantially tightened. To better control the problem and to extend the residence time of the additives in the Rauohgas stream, the use of fabric filters was underrun ". The advantages are the negative operating characteristics, an increase with the dust load increasing Druokverlust. Another fact of experience is the fact that effective simultaneous dust-gas cleaning must not exceed the filter surface weight of 30 nr / m ² h in fabric filters. In addition to the high measuring and control costs, there is thus a very large amount of space and investment required. Existing heat-generating systems thus exist hardly nooh an Ariwendungsohanoe. DD-OS 2209090.

In addition to the advantageous new two-stage additive process associated with recirculation of the additive aso to conversion into a microporous granular form using tissue filters, the overall deficiencies adhere to it. Although material ova rates can be achieved as low as 45-5 #, this trocar method does not Applied application nanospeed · DD-OS 248.289; DD-OS 248.290 ·

The efforts to reduce the high material use in trookenen gas cleaning duroh an increase de¬ the residence time of additives in Bauohgas, led to process developments using vortex and spine reactors as well as Sohütt- and Wanderfiltersohiohtanlageu. Hereby, the reaction conditions are ieothermal. It may be preferred to deposit only one pollutant component. DE-OS 2 · 401,570 ·

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In vertebral and vertebral reactors only relatively coarse sorbents can be boiled in the long run. * Duron the sorbent spins autogenous milling. Thus, if a sorbent particle crosses the boundary grain size, it will be discharged from the reactor and lost. In the interest of reducing material loss, the gas hourly rate is maintained at the lower limit, typically 1.2 lbs 0.2 m / s. This results in turn very large AnlagenabmesBungen, so that in particular multi-stage reactors can not be accommodated more. DD-OS 215,144.

From a larger number of patents bezüglioh the possibility of a simultaneous gas cleaning using Sohütt and / or Wandersohiohten has become known that olnd by forming a Filterkuohens in the dust efficiencies up to 99 % and in the binding of gaseous pollutants up to 85 % achievable. Both in the application of quiescent and non-stationary filter homing, filterhiohtone results in filterhousing typical of fabric filter operation, resulting in negative operational harshness.

It became known, for example, a moving bed process with carbonaceous granulated filter elements naoh DE-OS 2,911,712 in which Sohwefel- or nitrogen oxides, the latter with ammonia addition, can be removed from Rauohgasen * Here are Filterohioh; s with bed depths 2 1m used. The dust content of the gases must not exceed 1 g / m in continuous operation. The pressure loss reaches values up to 2500 Pa.

For a more extensive deposition, this process has been modified so that several moving beds have been used staggered in the flow direction "DE-OS 3,232,546,

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Another variation in cascade connection is found in DO-OS 236.083 ersiohtlloh. In the case of similar methods, low-level filter materials are used, as in the step-down method. "

The staggering of carbonaceous sorbents for flue gas cleaning is due to the relatively high oxygen content thereof and the high auto-ignition tendency of activated carbons, especially in solohen, which were produced from lignite, only. \ N A very narrow temperature range zwisohen between 330 ... 420 K possible that in sorption water-free raw materials and exhaust fumes this sorbent is very well capped by capillary condensation and surface passivation »Thus, the use of this type of adsorbent for flue gas purification has been limited to a single, large-scale application despite decades of process-wide profitability«

Methods and devices which operate in heat-generating systems which can be operated with ballast-grade fuels in the form of multi-stage, movable, sieve-like plans are disclosed in the patents DE-OS 442,514; DE-OS 2,325 * 695; DE-OS 3,325,712; DE-OS 3 «329« 567 known. The forms of movement of the bed or the bedding material are reohighly underestimated. Although the improvement in the operational characteristics which can be seen from these process solutions reduces the negative influence of the resulting filter cake, it does not annihilate it. Duroh irregular Besohüttungen and vortex effects, with high bed depth special? Strongly pronounced, it comes locally to Gasdurohbrüoken, which also lead to premature material discharge and thus a loss of material "Auoh special equipment more complex devices have not been able to cancel this serious defect. DE-OS 3,443,832; DE-OS 3,604,204.

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To date, with economically viable effort, a comprehensive, simultaneous dust / gas purification in steam generators operated with ballastless, low calorific fuels can always be carried out. Only very few of the many positive-looking, known reaction effects and precursor details could be used more effectively in combination with each other, as these effects often cancel each other out in Hirer's effect »

Object of the invention

The aim of the invention is, under improvement of the operating conditions duroh an increase in the sales rate erhebllohe saving of resources at trookenen flue gas cleaning, especially when your use ballastreioher, niederkalorlsoher fuels and / or substances, to reach ·

Explanation of the essence of the invention

The invention has the object, while maintaining the thermal stability of a .trookenen gas purification by means of alkaline earth, duroh a repeated recirculation of awlsohenseitlioh activated Sorptloneimateriai to allow a quantitatively more comprehensive flue gas cleaning · The so far as a result of the addition dusty or flyable, granular additives with increasing solid content of Rauohgase soaring Combustion and / or heat transfer disturbances, the increasing erosion of erosion, the highly polluting dedusting conditions must be counteracted, in particular in steam and hot water production plants fired with ballastreioher raw lignite coal *

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The object of the invention is achieved in which suitable as sorbent erdalkallhaltige Ho.ti- and / or substances in the form of hydrolysis-stable Makrogranalian, preferably in the form of smooth, spherical filter elements, repeated naoh an intermediate activation, which can be coupled auoh with a build-up granulation "In several staggered" moving thin SohUtt- or Wandersohiohten whose Bettdioke one, 2.öfaoh dee Each Granaliendurohmessers not substantially exceeds, in each case only as long as in the gas stream to be cleaned ge to be operated until the LUokenvolumen the respective Fllteraohioht with Flue dust and / or the backfill is possibly filled with a preceding rough exhaust gas desulphurisation process.

The characteristic feature of the present invention is that the division of the required bedliquoring latitude into a plurality of staggered thin filter panels, which are covered with different granule thimble sheets, further limits the turnover time of the filter materials as a function of the dust load. It is dabai deliberately to the formation of a so-called Filterkohohens verzlohtet The Druokverlust this modifiableon Filteraystems can compared to a gloiohstarkh Sohütt- and / odor Wanderböttfilters by more than 50 ··· to 80 % lowered d / arüber hinauo be set to a constant value · Duroh resonances excited by the gas flow, the deposition of the gaseous Sohadgaskomponenten can be significantly increased · In Bottohohselzahlen 3 ··. 20 h ^-1 for the sorbent 200 times higher dwell times, thus correspondingly higher reaction times, under isothermal conditions. Compared with the silent addition of dust-containing or air-permeable microgranules, the material conversion rate of 20 ··· 40 % can be almost doubled ·

The new, modi fi ed Pi ilter sy star is also suitable for flue gas cleaning in hot gas furnaces ζ.Β _β fire gas roo ting systems. Until now, only dust removal was possible in these plants, if at all. The arrangement of thin, in the loading of limited filter material aB in Temperaturbereloht around 1200 K can be used so targeted for the afterburning of both solid and auoh gaseous Brennstoffkompone.uten, but auimin to elimination of alkaline components in vapor and / or aerosol form ^ or in Gleiohem Driokverlust dio Gasdurohlässigkeit on the / j. This high rate of increase in gas permeability, which is not expected, by the inventively modified filter system in low-cost mode of operation opens up the possibility for a more extensive industrial application of the long-known basic principle that hitherto has been characterized by its large space requirement and unsatisfactory company characteristic a constantly increasing pressure loss, could be used little.

The new filter system is also characterized by the fact that both certain tower and soot gas components can be removed from the Rauoh and / or exhaust gases simultaneously when the filter bed graduation is divided among different heater sections, thus making the filter halves effective in different temperature ranges By varying the size of the gravel, with intermediate activation of the sorbed matter, with the addition of further potential sorption mass, in particular erosive dust fractions of certain grain size and thicknesses can be prematurely separated from the flue gas. "

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With the addition of, for example, ophthalmic sulphite-containing abscess into the macrogranulate, a more comprehensive stiokoxide reduction can be carried out in one or more filter stages. When Fllter-S- ¹ junctions are arranged in the outlet temperature range S.sub.QO.sub.K , it is also possible to include condensing soot-metal oxide impurities in the capillary system of the filter elements and by superimposing further sorption material in a form which can no longer be eluted. In a separate catfish, the method is suitable for filtering out crude oxygen condensate

exemplary

The invention will be explained in more detail below with reference to an exemplary embodiment in conjunction with FIG. 1. The process according to the invention is intended to be applied in a steam generator plant equipped with the Trooken-Kalkstein additive system.

In the lignite fired with lignite steam generator 1 and in its naohgesohalteten facilities such as the dust collector 2 and the additional exhaust gas heat exchanger 3 aoht are staggered arranged, in addition to different temperature ranges ce ce. thin hauls 6 to 13 are installed. Duroh the addition of kaolin fume to the fuel takes place. In the hearth, calcination of the primary additive and fumigation of the fumigant gas occurs. As a result, a lime calcareous asohe accumulates. "It is considered a potential resource for the next, far reaching; more comprehensive, erdalkallhaltige flue gas cleaning used in the new "process according to the invention ·

Duroh the installation of the thin Filterohiohten with a Sohlohtstärke, which corresponds to the twelve-diameter of the filter elements, in helzfläohenfreio Absohnltte the Rauohgaszüge now RUokstandsabsoheldung selectively selectively takes place in the first Filterohioht 6 come

With repeated filtering and build-up granulation In four classifying vortex levels intermittently activated, 15 mm 0 enlarged filter elements are used ₀ With the help of the Filterohioht 6 the coarse, sand-relieved asonefraction and remaining, unburnt solid fuel parts are removed from the rough gas Through the Rauohgasverwirbelung triggered by the Filterohloht under resolution of strands leads to M.ner spontaneous Naohverbrennung residual, still flammable, gas-like Sohadstoffkomponenten, such as Kohlenmonoxideö and hydrocarbons. Alkali-high vapors and / or aerosols formed in the furnace, which are produced as fuel in particular when so-called salted carbons are used, thus inevitably accumulate in the macroporous space in the macroporous space due to the high resonance of the gas flow in the container bed

The utilization of the filter heat is only carried out until 'the volume of the gas is filled up in accordance with the requirements of the art. Firstly, the traveling speed of the filter elements is matched with the above; ^# 3 ··· 4 ra / min, which emanates from a pile of bedspoons 15 · · · 20 h · The limitation of the dust discharge, consciously dispensing with the formation of a filter cooktop on the surface of the filter bed, serves to maintain the resonance constant, low pressure loss or the increased gas turbo rate compared to the quiescent or filter cake-covered conventional moving bed. In this way, the formation of limits around the sorbent, which is undesirable in the interest of a more efficient soot gas sorption, is minimized The above positive effect factors are also used in the following sohlohts with grading of filter element dimensions and increase in the intensity of movement of the bed. «

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Prepare the first, selective reduction of the raw material components of the raw material gas that render and erode the heating surfaces, leading to an immediate noticeable improvement of the steam generator operating conditions and to a low-sputtering operation of the sodium hydroxide heating surfaces. The discharge of the loaded filter mass of the oil is carried out on the burner NaOHN4. In this case, this residual volume is disposed of very effectively and simply. The lime-rich fly ash fractions remaining in the gas are now successively filtered with the aid of the filter oil with the elimination of further soy gases such as the hydrogen halide, as derived from residual sulfur dioxide. If required, a sorbent can be produced in the filter tubes 12 and 13 with the addition of reducing substances such as calcium sulfite, a substance from a Rauohgaswasoh- or Sprühsorptionsanlage, in the classifying Vorbelsohiohtanlage 5 in Rauohgastemperaturbereioh 360 · ο ο 4θΟ K , especially for a Stiokoxidemissionsminderung is being used·

Me discharged filter elements of stages 7 to 13 are sprayed at each Durohgang with water and so activated. In this case, the entrained quicklime fly ash dissolved and superficially applied to the granules processed in this form, the alkaline earth-rich Additivasohe serves as a raw material both for the construction of new filter elements ale the formation of a new active Oberfläohensohioht enlarging the Granaliendurohmessers, durohsohnittlioh by 0.4 mm per cycle The condensation of the oohwermetal oxide vapors, which are also present in traces in the flue gas of lignite-fired steam generators, is known only to a considerable extent after a Rauohgasabkühluig less than 500 K under aorosol formation ·

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In this ITom, these pollutants are also successfully removed from the flue gas by the thin filter materials 12 mi / ¹ 13 working in accordance with the invention ο There is thus a considerable increase in the irritation of hoohtoxlsoher substances on the surface of the granules. Duroh the subsequent build-up granulation under hydration and The gradual Rozlrkulation in higher temperature range «urcfangreioher zwisohenmineralisoher reactions, which cause a binding of Sohwermetalle · There is a nioht eluierbäres' safe Lagerb & res, deponieatabiles Abproduktο The conventional dedusting in the present case has the task Staubdurohbrüohe catch (buffer effect) 0

The process shown has a long residence time of the sorbent in the crude gas stream. The permanent activation with formation of thin sorbent soils leads to a considerable increase in the material turnover compared to conventional dry gas treatment processes with dusty or flyable microgranules Variant (two-stage method) in addition to an increase in the residence time of the primary additive. Overall, the new method allows both qualitatively and quantitatively the so-called gas components to eliminate the reduced cost of materials. "

Claims (2)

Erflndungsanspruoh A comprehensive dry gas purification method for the selective removal of dust, aerosol, gas and vapor soot components from Rauoh, Sohwel or other exhaust gases by means of a motive soot and / or volumetric water heating system by means of potential, inaccessible oxygen. rdalkallhalti.ger Roh- \ mä / oA "r Ahetoffen, au oh with the addition of catalysing or reducing masses characterized daduroh that sorbent as suitable raw materials and / or substances first bräu to hydrolysestablleia, monodlsporsen macrogranules" 1 mm 0, preferably smooth spherical granules, then repeated as filter elements under intermediate activation, which may be coupled with a build-up granulation, a plurality of _? Staggered arranged, moving thin Sohütt- or Wandersohlohten whose Bettdioke maximally a twentyfew of the equivalent Granaliendurohmeosers not üuersteigi ;, are used and thereby only as long in the gas stream to be operated to the effect, until the Luokenvolumen the respective Filterohioht with Verbrennungsrüokaitänden and / or the residue If necessary, the macrogranules loaded with flammable soad and / or substances are disposed of, or, if necessary, subjected to comminution, by post-combustion or, alternatively, by means of top-up granulation with a leach-resistant, landfill-stable surface oil. Method according to claim 1, characterized in that the staggering of the moving, thin soot and / or wandering hoses may be fanned out such that one or more moving thin fouling hoses of the system are distributed over the temperature range of 300 _{° to} 1300 _° K. A process as claimed in claim 1, characterized in that Eur activation "under built-up granulation both starting raw materials and / or substances are added to the filter elements with the addition of water to the filter elements, in this case a diameter increase sf 1 mm, preferably by 0.4 mm , entry" 4. A process as claimed in claims 1 to 3, characterized in that activated filter elements, preferably those with increased durometer, are introduced into one or more moving thin SohUtt- or Wandersohiohten of the system, which may be auiat lliat in a higher Temperaturberei ohiat, be recalculated. 5 * A method NaOH characterized in claims 1 Bi 4 that the bed movement variable characterizing with increasing dedusting, such _"0 wii'do the Sohwingfrequenz or Wandergesohwindigkelt increased B 6th method at the points 1 to 5 daduroh characterized in that the graded Durohmesservergrößerung the filter elements is not only in the interest of activation to improve the Absoheidebedingungen the gae and vaporous Soad components but auoh targeted for a better, selective dust separationβ is used 7c method of claims 1 to 6 daduroh characterized in that one or more moving thin Filterohiohten the system in the temperature range TJ ^ nI000 ♦., 1300 K used both for a selective Flugstaubabsoheidung than auoh for afterburning residual gaseous and / or solid unburned fuel components become" -ΊΟ- Method according to Claims 1 to 6, characterized in that one or more moving thin filter tubes of the system i ». the temperature range * T ("1000 ooo 1300 K in addition to a selective deposition of flue dust preferably be used for the separation of alkali vapors and / or their aerosols. 9 method according to points 1 to 6 daduroh characterized in that one or more moving dUnnc filter hoses of the system in the temperature range Tj ^ »700 ·· <> 1000 K are preferably used for the separation of hydrogen halides in addition to selective dust removal. The method of points 1 to 6 is characterized in that one or more moving thin filter layers of the system in the temperature range Tra * 400 ··· 700 K are preferred in addition to selective dust separation for an alkali-iso-oxidative stoichiocide bond with subsequent reduction the nitrogen oxides are used. 11 method according to points 1 to 6 daduroh characterized in that one or more moving thin Filterohiohten the system in the temperature range 300 ·· «700 K, in addition to a selective dust separation preferably for a binding of Sohwefeloxide or Sohwefelsaureaerosolen be used« 12. Method according to points 1 to 6 characterized in that one or more moving thin Filterohiohten the system in the temperature range 300 ... 500 K in addition to a selective dust separation are preferably used for the deposition of Sohwermetalloxiddämpfen or aerosols · 13 Method according to points 1 to 6 daduroh characterized in that one or more moving thin Filterohiohten the system in the temperature range 300 ··· 400 K in addition to a selective dust separation are preferably used for the separation of acid and / or water mist. Ί Se / At