WO1997002086A1 - Process for separating organic pollutants from flue gases by means of an adsorbent - Google Patents

Process for separating organic pollutants from flue gases by means of an adsorbent Download PDF

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Publication number
WO1997002086A1
WO1997002086A1 PCT/EP1996/002772 EP9602772W WO9702086A1 WO 1997002086 A1 WO1997002086 A1 WO 1997002086A1 EP 9602772 W EP9602772 W EP 9602772W WO 9702086 A1 WO9702086 A1 WO 9702086A1
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WIPO (PCT)
Prior art keywords
blast furnace
furnace coke
coke
flue gases
adsorbent
Prior art date
Application number
PCT/EP1996/002772
Other languages
German (de)
French (fr)
Inventor
Urban Cleve
Original Assignee
Hugo Petersen Gesellschaft Für Verfahrenstechnischen Anlagenbau Mbh & Co. Kg
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Publication date
Application filed by Hugo Petersen Gesellschaft Für Verfahrenstechnischen Anlagenbau Mbh & Co. Kg filed Critical Hugo Petersen Gesellschaft Für Verfahrenstechnischen Anlagenbau Mbh & Co. Kg
Priority to AU64162/96A priority Critical patent/AU6416296A/en
Publication of WO1997002086A1 publication Critical patent/WO1997002086A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/30—Particle separators, e.g. dust precipitators, using loose filtering material
    • B01D46/32—Particle separators, e.g. dust precipitators, using loose filtering material the material moving during filtering
    • B01D46/34—Particle separators, e.g. dust precipitators, using loose filtering material the material moving during filtering not horizontally, e.g. using shoots
    • 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
    • B01D53/02—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 by adsorption, e.g. preparative gas chromatography
    • B01D53/06—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 by adsorption, e.g. preparative gas chromatography with moving adsorbents, e.g. rotating beds
    • B01D53/08—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 by adsorption, e.g. preparative gas chromatography with moving adsorbents, e.g. rotating beds according to the "moving bed" method
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
    • B01D2253/10—Inorganic adsorbents
    • B01D2253/102—Carbon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
    • B01D2253/25—Coated, impregnated or composite adsorbents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
    • B01D2253/30—Physical properties of adsorbents
    • B01D2253/302—Dimensions
    • B01D2253/304—Linear dimensions, e.g. particle shape, diameter
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/20—Halogens or halogen compounds
    • B01D2257/206—Organic halogen compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/30—Sulfur compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/70—Organic compounds not provided for in groups B01D2257/00 - B01D2257/602
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/02—Other waste gases
    • B01D2258/0283—Flue gases
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2259/00—Type of treatment
    • B01D2259/40—Further details for adsorption processes and devices
    • B01D2259/40011—Methods relating to the process cycle in pressure or temperature swing adsorption
    • B01D2259/40077—Direction of flow
    • B01D2259/40081—Counter-current
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2259/00—Type of treatment
    • B01D2259/40—Further details for adsorption processes and devices
    • B01D2259/40083—Regeneration of adsorbents in processes other than pressure or temperature swing adsorption
    • B01D2259/40088—Regeneration of adsorbents in processes other than pressure or temperature swing adsorption by heating

Definitions

  • the invention relates to a method for separating and removing fly dusts and organic pollutants from flue gases by means of an adsorbent, such as is used, for example, when burning waste, in particular hazardous waste, and biomass, as well as in blast furnace and sintering plants and other combustion processes are incurred in which the combustion gas contains carbon, oxygen and chlorine.
  • an adsorbent such as is used, for example, when burning waste, in particular hazardous waste, and biomass, as well as in blast furnace and sintering plants and other combustion processes are incurred in which the combustion gas contains carbon, oxygen and chlorine.
  • the flue gases in question contain a number of organic, in particular aromatic, airborne dusts such as
  • PAH polycyclic aromatic hydrocarbons
  • PCB polychlorinated biphenyls
  • PCDD polybrominated dibenzodioxins
  • PCDF polychlorinated / polybrominated dibenzufurans
  • German patent 36 05 589 a method for removing sulfur dioxide and nitrogen oxides is known, in which lignite activated coke is used as an absorbent in an activated coke layer and high-quality activated carbon / activated coke is used in the following layers.
  • the brown coal coke has the particular disadvantage that it is too hard and therefore has high abrasion rates which lead to an increase in the dust load.
  • These systems are therefore very sensitive to the entry of airborne dust from upstream processes and are endangered by blockages, poor flow and self-heating.
  • the invention is therefore based on the object of proposing an adsorbent which avoids the problems arising from the foregoing and is equally suitable for removing pigeons and organic pollutants from combustion exhaust gases.
  • the solution to this problem is to remove the flue gases through a bed by coking a carbon containing material in a coke oven blast furnace coke.
  • blast furnace coke is also referred to as coke oven coke, metallurgical coke or foundry coke; the term “blast furnace coke” is used throughout the description and in the claims.
  • Blast furnace coke is a non-activated coke.
  • Coal again preferably hard coal, is preferably used as the carbon-containing material for the coking.
  • the use of e.g. Lignite or gffs. Wood is also considered.
  • Blast furnace coke differs significantly in its structure from lignite activated coke.
  • Blast furnace coke is characterized by a high piece and abrasion resistance; it is therefore ideally suited as an adsorbent with a long service life, because it changes only slightly during the various transport processes and the dust development is low.
  • the size of the blast furnace coke is preferably 3 to 30 mm, although very good results can also be achieved with particle sizes of 5 to 15 mm or even 20 mm.
  • the size of the piece results in a correspondingly high flow rate of the flue gas and therefore allows a smaller reactor volume with correspondingly lower investment costs.
  • the suitability of the blast furnace coke for separating the Airborne dust which at the same time brings about better separation of the organic pollutants, because some of them are associated with the airborne dust.
  • the flue gases are preferably passed through the blast furnace coke bed at a temperature of 100 to 300 ° C.
  • blast furnace coke as an adsorbent
  • activated coke and activated carbon there is no risk of self-heating, which in extreme cases can lead to a smoldering fire of the adsorbent and accordingly entails a considerable safety risk.
  • the comparatively low ignitability of the blast furnace coke also allows higher adsorption temperatures, which is generally of great importance when cleaning hot flue gases, because cooling down is then not necessary, or at least not to such an extent as is required for use activated carbon and coke with maximum bed temperatures of 180 ° C.
  • the rough, strongly jagged and sharp-edged surface of the blast furnace coke has, as has been found in experiments, a particularly good and high separating capacity even for the finest airborne dusts up to the aerosol range. This results in a particularly good separation of fly dust, which is partially covered with the organics, by adsorption of these substances on the carbon of the coke.
  • the adsorption of these substances does not, as for example in the adsorption of the gases SO2, SO3, HCl, HF, NO and others contained in the flue gases environmentally relevant harmful gases occur in the pore system of the activated carbon / coke, but on the carbon surface of the blast furnace coke.
  • the above-mentioned harmful gases are not adsorbed by blast furnace coke and therefore escape completely from the filter bed. This can be desirable in certain applications, for example if these gases are only present in low concentrations in the flue gas and thus have no environmental relevance, or if it makes sense to use a device according to the invention (blast furnace coke filter) by means of special processes to separate from the flue gases.
  • Ammonia can be added to the flue gas to reduce the nitrogen oxides. If SO2 is still present in the flue gas, a dust-like ammonium sulfate / ammonium hydrogen sulfate is formed, which can also be filtered off by the blast furnace coke. As a result, a relatively simple and inexpensive nitrogen oxide separation is achieved, especially since, as long as the ammonium drug sulfate is "sticky", it can be separated well and removed from the reactor.
  • the blast furnace coke is characterized by its high hardness. This minimizes the losses due to breakage and abrasion in a flow-through moving bed reactor in which the blast furnace coke is drawn off downwards.
  • the use of this adsorbent therefore also has a positive economic advantage.
  • the sensitivity of the blast furnace coke to self-heating or to the smoldering fires that occur is considerably lower. Studies have shown that self-heating begins in the activated carbon pore system. The larger of these pores is in the Angstrom range, particularly in the range between 20 and 500 ⁇ . Blast furnace coke lacks pores of this small diameter.
  • the heat generated can trigger self-heating even in the low temperature range from approximately 50 to 60 ° C. Because of the very large pores present in the blast furnace coke, the danger does not exist or only to a very small extent.
  • the blast furnace coke loaded with fly dust and the organic pollutants is removed from fly dust and possibly undersize after removal from the reactor in a sifter, this is separated in a filter; it can then be returned to the reactor and loaded again with fly dust and organic pollutants.
  • the blast furnace coke itself must then be brought to a high temperature of 400 ° C. and higher, preferably from 600 to 1000 ° C., to destroy the organic substances. This can also be done by using it as fuel in the process itself. When heated, the inorganic pollutants are destroyed and the blast furnace coke can then be used again as a filter material.
  • blast furnace coke over activated coal is that higher flow rates are possible. This leads to a smaller construction volume of the reactors and thus to a saving in investment costs or, with the same size of the reactors, to a reduced pressure loss and thus a saving in electrical energy.
  • the blast furnace coke is considerably cheaper than activated coal.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Treating Waste Gases (AREA)

Abstract

The invention pertains to a process for separating and removing flue dust and organic pollutants from flue gases by means of an adsorbent, wherein the flue gases are passed trhough a bed of blast furnace coke produced by coking a carbon-containing material, in particular hard coal, in a coking plant. The used coke can be regenerated at a temperature of 400 to 1000 °C or combusted.

Description

Verfahren zum Abscheiden von organischen Schadstoffen aus Rauchgasen mittels eines Adsorptionsmittels.Process for separating organic pollutants from flue gases using an adsorbent.
Die Erfindung bezieht sich auf ein Verfahren zum Ab¬ scheiden und Beseitigen von Flugstäuben und organischen Schadstoffen aus Rauchgasen mittels eines Adsorptions¬ mittels, wie sie beispielsweise beim Verbrennen von Müll, insbesondere Sondermüll, und Biomassen sowie in Hochofen- und Sinteranlagen sowie anderen Verbrennungs¬ prozessen anfallen, bei denen das Verbrennungsgas Koh¬ lenstoff, Sauerstoff und Chlor enthält.The invention relates to a method for separating and removing fly dusts and organic pollutants from flue gases by means of an adsorbent, such as is used, for example, when burning waste, in particular hazardous waste, and biomass, as well as in blast furnace and sintering plants and other combustion processes are incurred in which the combustion gas contains carbon, oxygen and chlorine.
Die betreffenden Rauchgase enthalten neben Flugstaub eine Reihe von organischen, insbesondere aromatischen Flugstäuben wieThe flue gases in question contain a number of organic, in particular aromatic, airborne dusts such as
polyzyklische aromatische Kohlenwasserstoffe (PAK) polychlorierte Biphenyle (PCB) polychlorierte/polybromierte Dibenzodioxine (PCDD) polychlorierte/polybromierte Dibenzufurane (PCDF),polycyclic aromatic hydrocarbons (PAH) polychlorinated biphenyls (PCB) polychlorinated / polybrominated dibenzodioxins (PCDD) polychlorinated / polybrominated dibenzufurans (PCDF),
die wegen ihrer Gesundheitsschädlichkeit und im Hin¬ blick auf ihre mangelnde Abbaubarkeit in der Natur und die dadurch bedingte Gefahr einer Anreicherung aus dem Rauchgas abgeschieden werden müssen.which have to be separated from the flue gas because of their harmfulness to health and in view of their lack of biodegradability in nature and the associated risk of enrichment.
Bekannt ist aus der deutschen Patentschrift 34 26 059 ein trockenes Verfahren zum adsorptiven Entfernen mitA dry process for adsorptive removal is known from German Patent 34 26 059
ORIGINALUNTERLAGEN Hilfe von Aktivkoks oder Aktivkohle, bei dem die Schad¬ stoffe im Desorptionsgas bei Temperaturen über 1000 °C thermisch zersetzt werden. Dieses Verfahren hat sich an sich bewährt, wenngleich die Verwendung von Aktivkoks und -kohle nicht nur mit Vorteilen verbunden ist. In diesem Zusammenhang sind der verhältnismäßig hohe Preis desAdsorptionsmittels und die Gefahr einer Eigenerwär¬ mung sowie der in Folge der verhältnismäßig geringen Härte erhebliche Abrieb zu nennen.ORIGINAL DOCUMENTS With the help of activated coke or activated carbon, in which the pollutants in the desorption gas are thermally decomposed at temperatures above 1000 ° C. This process has proven itself, although the use of activated coke and coal is not only associated with advantages. In this context, the relatively high price of the adsorbent and the risk of self-heating as well as the considerable abrasion resulting from the relatively low hardness are worth mentioning.
Weiter ist aus der deutschen Patentschrift 36 05 589 ein Vefahren zum Entfernen von Schwefeldioxid und Stickoxiden bekannt, bei dem in einer Aktivkoksschicht als Absorptionsmittel Braunkohlen-Aktivkoks und in fol¬ genden Schichten hochwertige Aktivkohle/Aktivkoks ein¬ gesetzt werden. Der Braunkohlekoks besitzt jedoch, wie sich im Betrieb gezeigt hat, vor allem den Nachteil, daß er eine zu geringe Härte aufweist und so hohe Ab¬ riebsraten mit sich bringt, die zu einer Erhöhung der Staubfracht führen. Diese Anlagen sind daher gegen Flugstaubeintrag aus vorgeschalteten Prozessen sehr empfindlich und durch Verstopfungen, schlechter Durch¬ strömung und eine Eigenerwärmung gefährdet.Furthermore, from German patent 36 05 589 a method for removing sulfur dioxide and nitrogen oxides is known, in which lignite activated coke is used as an absorbent in an activated coke layer and high-quality activated carbon / activated coke is used in the following layers. However, as has been shown in operation, the brown coal coke has the particular disadvantage that it is too hard and therefore has high abrasion rates which lead to an increase in the dust load. These systems are therefore very sensitive to the entry of airborne dust from upstream processes and are endangered by blockages, poor flow and self-heating.
Der Erfindung liegt daher die Aufgabe zugrunde, ein Ad¬ sorptionsmittel vorzuschlagen, das die sich aus vorste¬ hendem ergebenden Probleme vermeidet und sich in glei¬ cher Weise dazu eignet, Flugstäube und organische Schadstoffe aus Verbrennungsabgasen zu entfernen.The invention is therefore based on the object of proposing an adsorbent which avoids the problems arising from the foregoing and is equally suitable for removing pigeons and organic pollutants from combustion exhaust gases.
Die Lösung dieser Aufgabe besteht darin, die Rauchgase durch ein Bett aus durch Verkokung eines kohlenstoff- haltigen Materials in einer Kokerei erzeugten Hochofen¬ koks zu leiten.The solution to this problem is to remove the flue gases through a bed by coking a carbon containing material in a coke oven blast furnace coke.
Ein solcher Hochofenkoks wird auch als Kokereikoks, Hüttenkoks oder Gießereikoks bezeichnet; in der Be¬ schreibung und in den Ansprüchen wird der Begriff "Hochofenkoks" durchgehend benutzt. Hochofenkoks ist ein nicht aktivierter Koks.Such a blast furnace coke is also referred to as coke oven coke, metallurgical coke or foundry coke; the term "blast furnace coke" is used throughout the description and in the claims. Blast furnace coke is a non-activated coke.
Als kohlenstoffhaltiges Material für die Verkokung wird vorzugsweise Kohle, wiederum bevorzugt Steinkohle, ein¬ gesetzt. Der Einsatz von z.B. Braunkohle oder gffs. Holz wird auch in Betracht gezogen.Coal, again preferably hard coal, is preferably used as the carbon-containing material for the coking. The use of e.g. Lignite or gffs. Wood is also considered.
Hochofenkoks unterscheidet sich in seiner Struktur we¬ sentlich von Braunkohlen-Aktivkoks. Hochofenkoks zeich¬ net sich durch eine hohe Stück- und Abriebfestigkeit aus; er eignet sich daher hervorragend als Adsorptions¬ mittel von langer Lebensdauer, weil er sich bei den verschiedenen Transportvorgängen nur wenig verändert und die Staubentwicklung dabei gering ist.Blast furnace coke differs significantly in its structure from lignite activated coke. Blast furnace coke is characterized by a high piece and abrasion resistance; it is therefore ideally suited as an adsorbent with a long service life, because it changes only slightly during the various transport processes and the dust development is low.
Die Stückgröße des Hochofenkokses beträgt vorzugsweise 3 bis 30 mm, wenngleich sich sehr gute Ergebnisse auch bei Teilchengrößen von 5 bis 15 mm oder auch 20 mm er¬ zielen lassen.The size of the blast furnace coke is preferably 3 to 30 mm, although very good results can also be achieved with particle sizes of 5 to 15 mm or even 20 mm.
Die Stückgröße ergibt eine entsprechend hohe Durch¬ trittsgeschwindigkeit des Rauchgases und erlaubt daher ein geringeres Reaktorvolumen mit entsprechend niedri¬ geren Investitionskosten. Von besonderem Vorteil ist die Eignung des Hochofenkokses zum Abscheiden des Flugstaubes, die gleichzeitig ein besseres Abscheiden der organischen Schadstoffe mit sich bringt, weil diese zum Teil mit dem Flugstaub vergesellschaftet sind.The size of the piece results in a correspondingly high flow rate of the flue gas and therefore allows a smaller reactor volume with correspondingly lower investment costs. The suitability of the blast furnace coke for separating the Airborne dust, which at the same time brings about better separation of the organic pollutants, because some of them are associated with the airborne dust.
Vorzugsweise werden die Rauchgase mit einer Temperatur von 100 bis 300 °C durch das Hochofenkoksbett geleitet.The flue gases are preferably passed through the blast furnace coke bed at a temperature of 100 to 300 ° C.
Bei der Verwendung von Hochofenkoks als Adsorptionsmit¬ tel besteht im Gegensatz zu Aktivkoks und Aktivkohle nicht die Gefahr einer Eigenerwärmung, die im Extrem¬ fall zu einem Glimmbrand des Adsorptionsmittels führen kann und demgemäß ein erhebliches Sicherheitsrisiko mit sich bringt. Die vergleichweise geringe Zündfähigkeit des Hochofenkokses erlaubt zudem höhere Adsorptionstem¬ peraturen, was beim Reinigen in aller Regel heißer Rauchgase von großer Bedeutung ist, weil ein Herunter¬ kühlen dann nicht oder zumindest nicht in einem so er¬ heblichen Maße erforderlich ist, wie bei der Verwendung von Aktivkohle und -koks mit maximalen Bettemperaturen von 180 °C.When using blast furnace coke as an adsorbent, in contrast to activated coke and activated carbon, there is no risk of self-heating, which in extreme cases can lead to a smoldering fire of the adsorbent and accordingly entails a considerable safety risk. The comparatively low ignitability of the blast furnace coke also allows higher adsorption temperatures, which is generally of great importance when cleaning hot flue gases, because cooling down is then not necessary, or at least not to such an extent as is required for use activated carbon and coke with maximum bed temperatures of 180 ° C.
Die rauhe, stark zerklüftete und scharfkantige Oberflä¬ che des Hochofenkokses weist, wie sich in Experimenten herausgestellt hat, ein besonders gutes und hohes Ab¬ scheidevermögen auch für feinste Flugstäube bis zum Ae¬ rosolbereich auf. Dadurch wird eine besonders gute si¬ multane Abscheidung von Flugstaub, der partiell mit den Organika belegt ist, durch Adsorption dieser Stoffe am Kohlenstoff des Kokses erzielt. Versuche haben bestä¬ tigt, daß die Adsorption dieser Stoffe nicht, wie bei¬ spielsweise bei der Adsorption der in den Rauchgasen enthaltenen Gase SO2, SO3, HCI, HF, NO sowie weiterer umweltrelevanter Schadgase im Porensystem der Aktivkoh- len/Kokse erfolgt, sondern an der Kohlenstoff- Oberfläche des Hochofenkokses. Die vorerwähnten Schad¬ gase werden von Hochofenkoks nicht adsorbiert und tre¬ ten daher vollständig aus dem Filterbett aus. Dies kann in bestimmten Anwendungsfällen durchaus erwünscht sein, beispielsweise wenn diese Gase nur in niedrigen Konzen¬ trationen im Rauchgas vorliegen und so keine umweltre¬ levante Bedeutung haben, oder wenn es sinnvoll ist, die Gase erst nach einer erfindungsgemäßen Vorrichtung (Hochofenkoksfilter) durch spezielle Verfahren aus den Rauchgasen abzuscheiden.The rough, strongly jagged and sharp-edged surface of the blast furnace coke has, as has been found in experiments, a particularly good and high separating capacity even for the finest airborne dusts up to the aerosol range. This results in a particularly good separation of fly dust, which is partially covered with the organics, by adsorption of these substances on the carbon of the coke. Experiments have confirmed that the adsorption of these substances does not, as for example in the adsorption of the gases SO2, SO3, HCl, HF, NO and others contained in the flue gases environmentally relevant harmful gases occur in the pore system of the activated carbon / coke, but on the carbon surface of the blast furnace coke. The above-mentioned harmful gases are not adsorbed by blast furnace coke and therefore escape completely from the filter bed. This can be desirable in certain applications, for example if these gases are only present in low concentrations in the flue gas and thus have no environmental relevance, or if it makes sense to use a device according to the invention (blast furnace coke filter) by means of special processes to separate from the flue gases.
Zu einer Reduzierung der Stickoxide kann dem Rauchgas Ammoniak zudosiert werden. Soweit noch SO2 im Rauchgas vorhanden ist, bildet sich ein staubförmiges Ammonium- sulfat/Ammoniumhydrogensulfat, das ebenfalls vom Hoch¬ ofenkoks abgefiltert werden kann. Hierdurch wird eine relativ einfache und preiswerte Stickoxidabscheidung erzielt, zumal, soweit das Ammoniumdrogensulfat "klebrig" ist, es gut abgeschieden und aus dem Reaktor abgezogen werden kann.Ammonia can be added to the flue gas to reduce the nitrogen oxides. If SO2 is still present in the flue gas, a dust-like ammonium sulfate / ammonium hydrogen sulfate is formed, which can also be filtered off by the blast furnace coke. As a result, a relatively simple and inexpensive nitrogen oxide separation is achieved, especially since, as long as the ammonium drug sulfate is "sticky", it can be separated well and removed from the reactor.
Der Hochofenkoks zeichnet sich durch eine hohe Härte aus. Dadurch werden die Verluste durch Bruch und Abrieb in einem durchströmten Wanderbettreaktor, bei dem der Hochofenkoks nach unten abgezogen wird, minimiert. Der Einsatz dieses Adsorbens hat demnach auch einen positi¬ ven wirtschaftlichen Vorteil. Weiter ist die Empfind¬ lichkeit des Hochofenkokses gegen Eigenerwärmung bzw. entstehende Glimmbrände wesentlich geringer. So wurde in Untersuchungen nachgewiesen, daß die Eigenerwärmung im Porensystem der Aktivkohle beginnt. Die Größer die¬ ser Poren liegt im Angström-Bereich, besonders im Be¬ reich zwischen 20 bis 500 Ä. Poren dieses geringen Durchmessers fehlen bei Hochofenkoks. Wissenschaftliche Arbeiten belegen, daß die Ursache für die Eigenerwär¬ mung darin begründet ist, daß im engen Porensystem von Aktivkohle/-koks Kohlenstoff und Sauerstoff in atomarer Form vorliegen, was im Hochofenkoks nicht nachgewiesen werden konnte. Ursache der Eigenerwärmung ist die Ver¬ bindung der C-Atome mit O-Atomen nach der Formel:The blast furnace coke is characterized by its high hardness. This minimizes the losses due to breakage and abrasion in a flow-through moving bed reactor in which the blast furnace coke is drawn off downwards. The use of this adsorbent therefore also has a positive economic advantage. Furthermore, the sensitivity of the blast furnace coke to self-heating or to the smoldering fires that occur is considerably lower. Studies have shown that self-heating begins in the activated carbon pore system. The larger of these pores is in the Angstrom range, particularly in the range between 20 and 500 Å. Blast furnace coke lacks pores of this small diameter. Scientific studies prove that the reason for the self-heating is that carbon and oxygen are present in atomic form in the narrow pore system of activated carbon / coke, which could not be proven in blast furnace coke. The cause of self-heating is the connection of the C atoms with O atoms according to the formula:
CA + OA → co + WärmeCA + OA → co + heat
CA + 20A → co2 + Wärme.CA + 20 A → co 2 + heat.
Die entstehende Wärme kann eine Eigenerwärmung schon im niedrigen Temperaturbereich ab etwa 50 bis 60 °C auslö¬ sen. Wegen der beim Hochofenkoks vorliegenden sehr gro¬ ßen Poren besteht die Gefahr nicht oder nur in ganz ge¬ ringem Maße.The heat generated can trigger self-heating even in the low temperature range from approximately 50 to 60 ° C. Because of the very large pores present in the blast furnace coke, the danger does not exist or only to a very small extent.
Der mit Flugstaub und den organischen Schadstoffen be- ladene Hochofenkoks wird nach Abzug aus dem Reaktor in einem Sichter von Flugstaub und ggfs. Unterkorn be¬ freit, dieser wird in einem Filter abgeschieden; er kann danach in den Reaktor zurückgeführt und erneut mit Flugstaub und organischen Schadstoffen beladen werden. Der Hochofenkoks selbst muß zur Zerstörung der organi¬ schen Substanzen dann auf eine hohe Temperatur von 400 °C und höher, vorzugsweise von 600 bis 1000 °C, ge¬ bracht werden. Dies kann auch dadurch geschehen, daß er als Brennstoff im Prozeß selbst eingesetzt wird. Beim Erhitzen werden die anorganischen Schadstoffe zerstört und der Hochofenkoks kann dann wieder als Filtermateri¬ al eingesetzt werden.The blast furnace coke loaded with fly dust and the organic pollutants is removed from fly dust and possibly undersize after removal from the reactor in a sifter, this is separated in a filter; it can then be returned to the reactor and loaded again with fly dust and organic pollutants. The blast furnace coke itself must then be brought to a high temperature of 400 ° C. and higher, preferably from 600 to 1000 ° C., to destroy the organic substances. This can also be done by using it as fuel in the process itself. When heated, the inorganic pollutants are destroyed and the blast furnace coke can then be used again as a filter material.
Weitere Vorteile des Einsatzes von Hochofenkoks gegen¬ über aktivierten Kohlen liegen darin, daß höhere Durch¬ strömungsgeschwindigkeiten möglich sind. Dies führt zu einem kleineren Bauvolumen der Reaktoren und damit zur Ersparnis von Investitionskosten oder, bei gleicher Baugröße der Reaktoren, zu einem verminderten Druckver¬ lust und damit Ersparnis von elektrischer Energie. Wei¬ ter ist der Hochofenkoks wesentlich preiswerter als ak¬ tivierte Kohle. Another advantage of using blast furnace coke over activated coal is that higher flow rates are possible. This leads to a smaller construction volume of the reactors and thus to a saving in investment costs or, with the same size of the reactors, to a reduced pressure loss and thus a saving in electrical energy. In addition, the blast furnace coke is considerably cheaper than activated coal.

Claims

Patentansprüche; Claims;
1. Verfahren zum Abscheiden und Beseitigen von Flug¬ stäuben und organischen Schadstoffen aus Rauchgasen mittels eines Adsorptionsmittels dadurch gekenn¬ zeichnet, daß die Rauchgase durch ein Bett aus durch Verkokung eines kohlenstoffhaltigen Materials in einer Kokerei erzeugten Hochofenkoks geleitet werden.1. A method for separating and removing flue dust and organic pollutants from flue gases by means of an adsorbent, characterized in that the flue gases are passed through a bed of blast furnace coke produced by coking a carbonaceous material in a coking plant.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß durch Verkokung von Kohle, vorzugsweise Stein¬ kohle, gewonnener Hochofenkoks eingesetzt wird.2. The method according to claim 1, characterized in that blast furnace coke obtained by coking coal, preferably coal coal is used.
3. Verfahren nach Anspruch 1 oder 2, dadurch gekenn¬ zeichnet, daß der Hochofenkoks eine Teilchengröße von 3 bis 30 mm besitzt.3. The method according to claim 1 or 2, characterized gekenn¬ characterized in that the blast furnace coke has a particle size of 3 to 30 mm.
4. Verfahren nach einem der Anspruch 1 bis 3, dadurch gekennzeichnet, daß die Rauchgase mit einer Tempe¬ ratur von 100 bis 300 °C durch das Hochofenkoksbett geleitet werden.4. The method according to any one of claims 1 to 3, characterized in that the flue gases are passed through the blast furnace coke bed at a temperature of 100 to 300 ° C.
5. Verfahren nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß der erschöpfte Hochofenkoks bei einer Temperatur von 400 bis 1000 °C regneriert oder verbrannt wird.5. The method according to any one of claims 1 to 4, characterized in that the exhausted blast furnace coke at at a temperature of 400 to 1000 ° C is rained or burned.
6. Verfahren nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß von Flugstaub und Unterkorn be¬ freiter Hochofenkoks erneut eingesetzt wird.6. The method according to any one of claims 1 to 5, characterized in that blast furnace coke be¬ freed of fly dust and undersize is used again.
7. Verfahren nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß dem Rauchgas Ammoniak zugesetzt wird.7. The method according to any one of claims 1 to 6, characterized in that ammonia is added to the flue gas.
8. Vorrichtung zur Durchführung des Verfahrens nach einem der Ansprüche 1 bis 7, gekennzeichnet durch einen Reaktor mit mehreren Hochofenkoksschichten und einem Abzug zum schichtweisen Ausschleusen des Hochofenkokses. 8. Device for carrying out the method according to one of claims 1 to 7, characterized by a reactor with a plurality of blast furnace coke layers and a fume cupboard for discharging the blast furnace coke in layers.
PCT/EP1996/002772 1995-06-30 1996-06-25 Process for separating organic pollutants from flue gases by means of an adsorbent WO1997002086A1 (en)

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DE1995123866 DE19523866A1 (en) 1995-06-30 1995-06-30 Airborne dust separation process

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DE19711840A1 (en) * 1997-03-21 1998-10-01 Petersen Hugo Verfahrenstech Process for removing pollutants in low concentration, especially chlorinated hydrocarbons and possibly heavy metals, from exhaust gases
DE102009018059B4 (en) 2009-04-21 2015-04-02 Erwin Koppe Keramische Heizgeräte GmbH Method and device for reducing the proportion of fine dust in the exhaust air of a heater
DE102010051080A1 (en) 2010-11-12 2012-05-16 Erwin Koppe Keramische Heizgeräte GmbH Method and device for reducing the proportion of fine dust in the exhaust air of a solid fuel burning small fire system

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