WO1993000983A1 - Process for cleaning an exhaust gas containing sulphur dioxide and possibly other pollutants - Google Patents

Process for cleaning an exhaust gas containing sulphur dioxide and possibly other pollutants Download PDF

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Publication number
WO1993000983A1
WO1993000983A1 PCT/EP1992/001074 EP9201074W WO9300983A1 WO 1993000983 A1 WO1993000983 A1 WO 1993000983A1 EP 9201074 W EP9201074 W EP 9201074W WO 9300983 A1 WO9300983 A1 WO 9300983A1
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Prior art keywords
mercury
gypsum
washing liquid
exhaust gas
washing
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PCT/EP1992/001074
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German (de)
French (fr)
Inventor
Ulrich Mohn
Ryszard Kubisa
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L. & C. Steinmüller Gmbh
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Publication of WO1993000983A1 publication Critical patent/WO1993000983A1/en

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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
    • B01D53/64—Heavy metals or compounds thereof, e.g. mercury
    • 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
    • B01D53/501—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F11/00—Compounds of calcium, strontium, or barium
    • C01F11/46—Sulfates
    • C01F11/464—Sulfates of Ca from gases containing sulfur oxides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G13/00—Compounds of mercury
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G13/00—Compounds of mercury
    • C01G13/003—Preparation involving a liquid-liquid extraction, an adsorption or an ion-exchange

Definitions

  • the invention relates to a method for purifying an exhaust gas containing sulfur dioxide, mercury and possibly other pollutants, in which the exhaust gas is dedusted and washed in at least one stage with a calcium-containing washing liquid and in which the calcium sulfite formed with the addition of air in calcium sulfate (gypsum) is converted and then calcium sulfate-containing washing liquid is removed and gypsum is separated from the removed washing liquid.
  • gypsum calcium sulfate
  • a cleaning method with two-stage wet washing is known.
  • the first wash stage is used for cooling the flue gas and for the separation of other harmful gases such as HF, HC1 and heavy metals, while the second wash stage is used for S0 2 separation and the adjustment of the clean gas values.
  • Solids-containing washing liquid is drawn off from the bottom of both washing stages and fed to a thickener.
  • the thickened washing liquid is fed to a filter press. If mercury is contained to a large extent in the flue gas as a divalent ion, mercury is introduced in the known method via the thickener into the solid matter withdrawn from the filter press, which consists essentially of gypsum. This mercury entry limits the use of gypsum.
  • This object is achieved in that a chemical which converts the mercury into a water-insoluble compound and / or an adsorbent which adsorbs the mercury is added to the exhaust gas before the washing or the washing liquid itself and the water-insoluble compound or the laden adsorbent when the gypsum is separated off from the withdrawn washing liquid is discharged with the waste water.
  • Alkali sulfide compounds and selenium sulfide compounds, as well as iodine or sulfur in solid form, in particular sulfur bloom, are preferably suitable as the chemical leading to a water-insoluble mercury compound, which is preferably added to the flue gas before the first washing stage.
  • Sodium sulfides such as sodium polysulfide Na 2 S ⁇ or sodium monosulfide Na2S are particularly preferred.
  • the selenium compounds include in particular the selenium disulfide SeS2. mixtures of the chemicals can be used.
  • Granular carbon-containing adsorbents such as lignite or hard coal activated coke / coal, or other fine-particle adsorbents such as diatomaceous earth or activated Al2O3 are particularly suitable as adsorbents.
  • About the adsorbents in the sense of the present invention also include gels such as B silica gel, which can absorb the mercury.
  • the chemical or the adsorbent leading to the sparingly soluble mercury compound is preferably added to the exhaust gas before the first stage.
  • Mercury compounds or the mercury-laden adsorbent when separating the gypsum from the removed washing liquid is possible because the particles of the sparingly soluble mercury compound and the adsorbent particles differ in terms of their particle size distribution, shape and / or density from that in the main scrubber and possibly in the pre-scrubber differentiate produced plaster. It can A different parameter may be sufficient to achieve the separation with the waste water from the gypsum.
  • the particles of the poorly soluble mercury compounds have a flaky shape and thus differ significantly from the gypsum crystals, which in particular have an elongated shape.
  • the adsorbent particles can be assumed to have a much lower density than the gypsum crystals. In this way, it is possible to separate the mercury compounds or the adsorbed mercury from the gypsum when the gypsum is separated from the washing liquid with the wastewater from the dewatering and separation stage.
  • a method is thus specified in which, surprisingly, with a process step which is already present per se, namely the separation of gypsum with drainage, it is also possible to keep the mercury away from the gypsum; the dewatering and separation stage only has to respond to at least one of the parameters shown above.
  • a combination of a cyclone station with a downstream belt filter or a centrifuge, in particular an overflow centrifuge, is particularly suitable for separating the mercury from the gypsum while draining the gypsum.
  • the addition is to be carried out in such a way that a reaction time which is sufficient for the reaction to the water-insoluble mercury compounds is achieved before entering the at least one washing stage.
  • the aftertreatment of the waste water to remove the insoluble mercury compounds or the activated carbon particles loaded with mercury is carried out in a known manner.
  • Fig. 1 shows a procedure in which the dewatering takes place with the aid of a cyclone station and downstream band filter
  • Fig. 2 shows a procedure in which the dewatering takes place with a centrifuge.
  • the dedusted raw gas to be cleaned is fed via line 1 to an HCl scrubber 2, to which a scrubbing circuit 3 is assigned. Via a line 4 At a predetermined distance from the head 2a of the HCl scrubber, sodium monosulfite is supplied, which together with the mercury contained in the raw gas stream in the form of HgCl 2 according to the following equation:
  • the water-insoluble mercury compounds are introduced into the liquid of the washing circuit 3.
  • the gas cooled in the HC1 washer and freed from HC1 and possibly other pollutants is transferred via line 5 into a SO ⁇ ashtray 6, to which a washing circuit 7 is assigned and in which the main part of S0 2 is removed from the exhaust gas.
  • Lime milk is fed to both washers via a line 8 with branch lines 8a and 8b, this being fed via line 8a to adjust the pH in the HC1 scrubber 2, while the larger part is fed via line 8b to the SC ⁇ scrubber to form calcium sulfite is fed.
  • Both washers are still supplied with air via lines 9 leading to the laundry sump in order to convert the calcium sulfite formed to calcium sulfate.
  • a chemical such as the product marketed under the trade name METALLCLEAN is fed to the scrubber via line 10, while one is fed via line 11 to the scrubber 6
  • Chemical such as the product sold by Degussa under the name TMT 15, a 2.4.6-trimercaptotriazine, trisodium solution.
  • Washing liquid is discharged from the circuits 3 and 7 via the lines 12 and 13 and fed to a collecting container 14.
  • Loaded washing liquid is fed to a dewatering assembly 15 from this collecting container 14. which consists of a cyclone station 16 and a downstream band filter 17.
  • the overflow of the cyclone station is fed via a line 18 and the waste water of the belt filter 17 via a line 19 to a collecting tank 20 from which the waste water is drawn off.
  • the poorly soluble mercury compound is discharged with the overflow liquid via line 18.
  • washing liquid is fed from the collecting container 14 to a drainage assembly 16 which has an overflow centrifuge 21.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Inorganic Chemistry (AREA)
  • Environmental & Geological Engineering (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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Abstract

In a process for cleaning an exhaust gas containing sulphur dioxide and possibly other pollutants, the exhaust gas is freed of dust and washed in at least one stage with a calcium-containing washing liquid and the calcium sulphite formed is converted into calcium sulphate (gypsum) with the supply of air. Then the washing liquid containing gypsum is extraded and gypsum is separated from the extracted washing liquid. In order to produce gypsum containing no mercury, a chemical converting the mercury into a water-insoluble compound and/or an adsorber adsorbing the mercury is added to the exhaust gas before washing or to the washing liquid itself and the water-insoluble compound or the charged adsorber is discharged with the waste water during the separation of the gypsum from the washing liquid extracted.

Description

Beschreibung description
Verfahren zum Reinigen eines Schwefeldioxid und ggf. andere Schadstoffe enthaltenden AbgasesProcess for cleaning a sulfur dioxide and possibly other exhaust gas containing pollutants
Die Erfindung betrifft ein Verfahren zum Reinigen eines Schwefeldioxid, Quecksilber und ggf. andere Schadstoffe enthaltenden Abgases, bei dem das Abgas entstaubt und in mindestens einer Stufe mit einer calciumhaltigen Waschflüssigkeit gewaschen wird und bei dem das gebildete Calciumsulfit unter Zufuhr von Luft in Calciumsulfat (Gips) umgewandelt wird und danach calciumsulfathaltige Waschflüssigkeit abgezogen und aus der abgezogenen Waschflüssigkeit Gips abgetrennt wird.The invention relates to a method for purifying an exhaust gas containing sulfur dioxide, mercury and possibly other pollutants, in which the exhaust gas is dedusted and washed in at least one stage with a calcium-containing washing liquid and in which the calcium sulfite formed with the addition of air in calcium sulfate (gypsum) is converted and then calcium sulfate-containing washing liquid is removed and gypsum is separated from the removed washing liquid.
Aus der DE-Z Chem.-Ing.-Tech. 61 (1989) Nr. 4, S. 282 - 287, insbesondere Abb. 4 und zugehörige Beschreibung, ist ein Reinigungsverfahren mit zweistufiger Naßwäsche bekannt. Die erste Waschstufe dient zur Rauchgaskühlung und zur Abscheidung von weiteren Schadgasen wie HF, HC1 und Schwermetallen, während die zweite Waschstufe der S02-Abscheidung und der Einstellung der Reingaswerte dient.From DE-Z Chem.-Ing.-Tech. 61 (1989) No. 4, pp. 282-287, in particular Fig. 4 and associated description, a cleaning method with two-stage wet washing is known. The first wash stage is used for cooling the flue gas and for the separation of other harmful gases such as HF, HC1 and heavy metals, while the second wash stage is used for S0 2 separation and the adjustment of the clean gas values.
Aus dem Sumpf beider Waschstufen wird feststoffhaltige Waschflüssigkeit abgezogen und einem Eindicker zugeführt. Die eingedickte Waschflüssigkeit wird einer Filterpresse zugeführt. Wenn im Rauchgas in größerem Umfang Quecksilber überwiegend als zweiwertiges Ion enthalten ist, wird dies Quecksilber bei dem bekannten Verfahren über den Eindicker in den aus der Filterpresse abgezogenen Feststoff, der im wesentlichen aus Gips besteht, eingetragen. Dieser Quecksilbereintrag beschränkt die Nützungsmöglichkeit des Gipses.Solids-containing washing liquid is drawn off from the bottom of both washing stages and fed to a thickener. The thickened washing liquid is fed to a filter press. If mercury is contained to a large extent in the flue gas as a divalent ion, mercury is introduced in the known method via the thickener into the solid matter withdrawn from the filter press, which consists essentially of gypsum. This mercury entry limits the use of gypsum.
Es ist die Aufgabe der vorliegenden Erfindung ein Verfahren der vorstehend genannten Art anzugeben, bei dem dafür Sorge getragen wird, daß Quecksilber nicht in das entwässerte Produkt eingetragen wird.It is the object of the present invention to provide a method of the type mentioned above, in which care is taken to ensure that mercury is not introduced into the dewatered product.
Diese Aufgabe wird dadurch gelöst, daß dem Abgas vor dem Waschen oder der Waschflüssigkeit selbst eine das Quecksilber in eine wasserunlösliche Verbindung überführende Chemikalie und/oder ein das Quecksilber adsorbierendes Adsorptionsmittel zugegeben wird und die wasserunlösliche Verbindung oder das beladene Adsorptionsmittel bei der Abtrennung des Gipses von der abgezogenen Waschflüssigkeit mit dem Abwasser abgeführt wird.This object is achieved in that a chemical which converts the mercury into a water-insoluble compound and / or an adsorbent which adsorbs the mercury is added to the exhaust gas before the washing or the washing liquid itself and the water-insoluble compound or the laden adsorbent when the gypsum is separated off from the withdrawn washing liquid is discharged with the waste water.
Als zu einer wasserunlöslichen Quecksilberverbindungen führenden Chemikalie, die vorzugsweise dem Rauchgas vor der ersten Waschstufe zugeführt wird, eignen sich vorzugsweise Alkalisulfidverbindungen und Selensulfidverbindungen, sowie Jod oder Schwefel in Feststoffform, insbesondere Schwefelblüte. Besonders bevorzugt sind hierbei die Natriumsulfide wie Natriumpolysulfide Na2Sχ oder Natriummonosulfid Na2S. Zu den Selenverbindungen gehört insbesondere das Selendisulfid SeS2• Ggf. können Mischungen der Chemikalien eingesetzt werden.Alkali sulfide compounds and selenium sulfide compounds, as well as iodine or sulfur in solid form, in particular sulfur bloom, are preferably suitable as the chemical leading to a water-insoluble mercury compound, which is preferably added to the flue gas before the first washing stage. Sodium sulfides such as sodium polysulfide Na 2 S χ or sodium monosulfide Na2S are particularly preferred. The selenium compounds include in particular the selenium disulfide SeS2. mixtures of the chemicals can be used.
Als Adsorptionsmittel eignen sich insbesondere körnige kohlenstoffhaltige Adsorptionsmittel, wie Braunkohlen- oder Steinkohlenaktivkoks/Kohle, oder andere feinteilige Adsorptionsmittel wie Kieselgur oder aktiviertes AI2O3. Zu den Adsorptionsmitteln im Sinne der vorliegenden Erfindung gehören auch Gele wie z. B Kieselgel, die das Quecksilber absorbieren können.Granular carbon-containing adsorbents, such as lignite or hard coal activated coke / coal, or other fine-particle adsorbents such as diatomaceous earth or activated Al2O3 are particularly suitable as adsorbents. About the adsorbents in the sense of the present invention also include gels such as B silica gel, which can absorb the mercury.
Wenn - wie bei dem bekannten Verfahren - eine mehrstufige Wäsche vorgesehen ist, erfolgt vorzugsweise die Zugabe der zu der schwerlöslichen Quecksilberverbindung führenden Chemikalie oder des Adsorptionsmittels in das Abgas vor der ersten Stufe.If, as in the known method, a multi-stage scrubbing is provided, the chemical or the adsorbent leading to the sparingly soluble mercury compound is preferably added to the exhaust gas before the first stage.
Eine Abscheidung der wasserunlöslichenA separation of the water-insoluble
Quecksilberverbindungen oder der mit Quecksilber beladenen Adsorptionsmittel bei der Abtrennung des Gipses von der abgezogenen Waschflüssigkeit ist möglich, weil die Teilchen der schwer löslichen Quecksilberverbindung und die Adsorptionsmittelteilchen sich hinsichtlich ihrer Korngrößenverteilung, Form und/oder Dichte von dem in dem Hauptwäscher und ggf. in dem Vorwäscher erzeugten Gips unterscheiden. Es kann u. U. bereits ein unterschiedlicher Parameter ausreichen, um die Abtrennung mit dem Abwasser vom Gips zu erreichen.Mercury compounds or the mercury-laden adsorbent when separating the gypsum from the removed washing liquid is possible because the particles of the sparingly soluble mercury compound and the adsorbent particles differ in terms of their particle size distribution, shape and / or density from that in the main scrubber and possibly in the pre-scrubber differentiate produced plaster. It can A different parameter may be sufficient to achieve the separation with the waste water from the gypsum.
Es ist davon auszugehen, daß die Teilchen der schwer löslichen Quecksilberverbindungen eine flockige Form aufweisen und sich somit deutlich von den insbesondere eine längliche Form aufweisenden Gipskristallen unterscheiden. Bei den Adsorptionsmittelteilchen ist davon auszugehen, daß diese eine wesentlich geringere Dichte als die Gipskristalle aufweisen. Auf diese Weise ist es möglich, bei der Abtrennung des Gipses aus der Waschflüssigkeit mit dem Abwasser der Entwässerungs- und Abtrennstufe die Quecksilberverbindungen bzw. das adsorbierte Quecksilber vom Gips abzutrennen. Es ist somit ein Verfahren angegeben, bei dem in überraschender Weise mit einer an sich schon vorhandenen Verfahrensstufe, nämlich der Gipsabtrennung mit Entwässerung, zugleich ein Fernhalten des Quecksilbers aus dem Gips ermöglicht wird; die Entwässerungs- und Abtrennstufe muß nur auf mindestens einen der oben aufgezeigten Parameter ansprechen. VIt can be assumed that the particles of the poorly soluble mercury compounds have a flaky shape and thus differ significantly from the gypsum crystals, which in particular have an elongated shape. The adsorbent particles can be assumed to have a much lower density than the gypsum crystals. In this way, it is possible to separate the mercury compounds or the adsorbed mercury from the gypsum when the gypsum is separated from the washing liquid with the wastewater from the dewatering and separation stage. A method is thus specified in which, surprisingly, with a process step which is already present per se, namely the separation of gypsum with drainage, it is also possible to keep the mercury away from the gypsum; the dewatering and separation stage only has to respond to at least one of the parameters shown above. V
Um die Flockenbildung und/oder die Abscheidung von ggf. noch vorhandenem Quecksilber in der flüssigen Phase zu erleichtern, ist es daher zweckmäßig, wenn der Waschflüssigkeit der mindestens einen Waschstufe mindestens eine Chemikalie zugesetzt wird.In order to facilitate the formation of flakes and / or the separation of any mercury that may still be present in the liquid phase, it is therefore expedient if at least one chemical is added to the washing liquid in the at least one washing step.
Für die Abtrennung des Quecksilbers vom Gips unter gleichzeitiger Entwässerung des Gipses eignet sich insbesondere eine Kombination von Zyklonstation mit nachgeschaltetem Bandfilter oder eine Zentrifuge, insbesondere ÜberlaufZentrifuge.A combination of a cyclone station with a downstream belt filter or a centrifuge, in particular an overflow centrifuge, is particularly suitable for separating the mercury from the gypsum while draining the gypsum.
Bei Zugabe der zur schwerlöslichen Quecksilberverbindung führenden Chemikalien in das Abgas vor der ersten Waschstufe ist die Zugabe so durchzuführen, daß vor Eintritt in die mindestens eine Waschstufe eine Reaktionszeit erreicht wird, die für die Reaktion zu den wasserunlöslichen Quecksilberverbindungen ausreichend ist.If the chemicals leading to the sparingly soluble mercury compound are added to the exhaust gas before the first washing stage, the addition is to be carried out in such a way that a reaction time which is sufficient for the reaction to the water-insoluble mercury compounds is achieved before entering the at least one washing stage.
Die Nachbehandlung des Abwassers zum Entfernen der unlöslichen Quecksilberverbindungen bzw. der mit Quecksilber beladenen Aktivkohleteilchen geschieht in bekannter weise.The aftertreatment of the waste water to remove the insoluble mercury compounds or the activated carbon particles loaded with mercury is carried out in a known manner.
Die Erfindung soll nun in zwei Verfahrensvarianten anhand der beigefügten Figuren näher erläutert werden. Es zeigt:The invention will now be explained in more detail in two process variants with reference to the attached figures. It shows:
Fig. 1 eine Verfahrensführung, bei der die Entwässerung mit Hilfe einer Zyklonstation und nachgeschaltetem Bandfilter erfolgt, undFig. 1 shows a procedure in which the dewatering takes place with the aid of a cyclone station and downstream band filter, and
Fig. 2 eine Verfahrensführung, bei der die Entwässerung mit einer Zentrifuge erfolgt.Fig. 2 shows a procedure in which the dewatering takes place with a centrifuge.
Das entstaubte und zu reinigende Rohgas wird über eine Leitung 1 einem HCl-Wäscher 2 zugeführt, dem ein Waschkreislauf 3 zugeordnet ist. Über eine Leitung 4 wird in vorgegebenem Abstand vom Kopf 2a des HCl-Wäschers Natriummonosulfit zugeführt, das zusammen mit dem im Rohgasstrom in Form von HgCl2 enthaltenen Quecksilber gemäß folgender Gleichung:The dedusted raw gas to be cleaned is fed via line 1 to an HCl scrubber 2, to which a scrubbing circuit 3 is assigned. Via a line 4 At a predetermined distance from the head 2a of the HCl scrubber, sodium monosulfite is supplied, which together with the mercury contained in the raw gas stream in the form of HgCl 2 according to the following equation:
(1) Na2S + HgCl2 —^ HgsJ' + 2NaCl(1) Na 2 S + HgCl 2 - ^ HgsJ '+ 2NaCl
zu einer unlösbaren Quecksilberverbindung noch vor Eintritt in den Wäscher reagiert. Die wasserunlöslichen Quecksilberverbindungen werden in die Flüssigkeit des Waschkreislaufs 3 eingetragen.reacted to an insoluble mercury compound before entering the scrubber. The water-insoluble mercury compounds are introduced into the liquid of the washing circuit 3.
Das in dem HC1-Waseher gekühlte und von HC1 und ggf. anderen Schadstoffen befreite Gas wird über Leitung 5 in einen SO^- äscher 6 überführt, dem ein Waschkreislauf 7 zugeordnet ist und in dem der Hauptteil an S02 aus dem Abgas entfernt wird. Beiden Wäschern wird über eine Leitung 8 mit Zweigleitungen 8a und 8b Kalkmilch zugeführt, wobei diese über Leitung 8a zur Einstellung des pH-Werts im HC1- Wäscher 2 zugeführt wird, während über Leitung 8b der größere Teil dem SC^-Wäscher zur Bildung von Calciumsulfit zugeführt wird. Beide Wäscher werden über zum Wäschersumpf führende Leitungen 9 noch mit Luft beaufschlagt, um das gebildete Calciumsulfit zu Calciumsulfat umzuwandeln. Zur evtl. weiteren Abscheidung von Quecksilber in der flüssigen Phase und ggf. zur Verbesserung bzw. Einstellung der Teilchenform der wasserunlöslichen Quecksilberverbindungen wird dem Wäscher über Leitung 10 eine Chemikalie wie das unter dem Handelsnamen METALLCLEAN vertriebene Produkt zugeführt, während dem Wäscher 6 über Leitung 11 eine Chemikalie wie das von der Fa. Degussa unter der Bezeichnung TMT 15 vertriebene Produkt zugeführt wird, eine 2.4.6-Trimercaptotriazin, Trinatrium-Lösung.The gas cooled in the HC1 washer and freed from HC1 and possibly other pollutants is transferred via line 5 into a SO ^ ashtray 6, to which a washing circuit 7 is assigned and in which the main part of S0 2 is removed from the exhaust gas. Lime milk is fed to both washers via a line 8 with branch lines 8a and 8b, this being fed via line 8a to adjust the pH in the HC1 scrubber 2, while the larger part is fed via line 8b to the SC ^ scrubber to form calcium sulfite is fed. Both washers are still supplied with air via lines 9 leading to the laundry sump in order to convert the calcium sulfite formed to calcium sulfate. To possibly further separate mercury in the liquid phase and, if necessary, to improve or adjust the particle shape of the water-insoluble mercury compounds, a chemical such as the product marketed under the trade name METALLCLEAN is fed to the scrubber via line 10, while one is fed via line 11 to the scrubber 6 Chemical such as the product sold by Degussa under the name TMT 15, a 2.4.6-trimercaptotriazine, trisodium solution.
Über die Leitungen 12 und 13 wird aus den Kreisläufen 3 bzw. 7 Waschflüssigkeit abgeführt und einem Sammelbehälter 14 zugeführt. Aus diesem Sammelbehälter 14 wird beladene Waschflüssigkeit einer Entwässerungsbaugruppe 15 zugeführt. die aus einer Zyklonstation 16 und einem nachgeschalteten Bandfilter 17 besteht. Der Überlauf der Zyklonstation wird über eine Leitung 18 und das Abwasser des Bandfilters 17 über eine Leitung 19 einem Sammelbehälter 20 zugeführt, aus dem das Abwasser abgezogen wird. Die schwer lösliche Quecksilberverbindung wird mit der Überlaufflussigkeit über Leitung 18 abgeführt.Washing liquid is discharged from the circuits 3 and 7 via the lines 12 and 13 and fed to a collecting container 14. Loaded washing liquid is fed to a dewatering assembly 15 from this collecting container 14. which consists of a cyclone station 16 and a downstream band filter 17. The overflow of the cyclone station is fed via a line 18 and the waste water of the belt filter 17 via a line 19 to a collecting tank 20 from which the waste water is drawn off. The poorly soluble mercury compound is discharged with the overflow liquid via line 18.
Bei der Ausführungsform gemäß Variante 2 wird Waschflüssigkeit aus dem Sammelbehälter 14 einer Entwässerungsbaugruppe 16 zugeführt, die eine ÜberlaufZentrifuge 21 aufweist.In the embodiment according to variant 2, washing liquid is fed from the collecting container 14 to a drainage assembly 16 which has an overflow centrifuge 21.
In der vorstehenden Verfahrensbeschreibung und in den Figuren 1 und 2 sind zur Vereinfachung der Darstellung Zusatz- und UmlaufWasserleitungen nicht gesondert dargestellt, da sie zum Verständnis der vorliegenden Erfindung nicht beitragen.In the above description of the method and in FIGS. 1 and 2, additional and circulating water pipes are not shown separately to simplify the illustration, since they do not contribute to an understanding of the present invention.
Während bei den bisher beschriebenen Verfahren die Chemikalienzugabe in die Gasstrecke vor HCl-Wäscher 2 erfolgt, ist es auch möglich, entsprechende Chemikalien dem Kreislauf 3 zuzugeben. Weiterhin ist es möglich, bei Einsatz von Adsorptionsmitteln diese entweder dem Rohgas in Leitung 1 oder dem Kreislauf des Wäschers 3 zuzusetzen (der Kreislauf besteht jeweils aus Wäschersumpf, Umwälzpumpe, Rückführleitung und mindestens einer Sprühebene). Wird auf einen Vorwäscher verzichtet und nur ein Sθ2~Wäscher betrieben, gilt für die Zugabe der zu einer unlösbaren Quecksilberverbindung führenden Verbindungen bzw. der Adsorptionsmittel Entsprechendes.While in the processes described so far the chemicals are added to the gas line upstream of the HCl scrubber 2, it is also possible to add appropriate chemicals to the circuit 3. Furthermore, when using adsorbents, it is possible to add them either to the raw gas in line 1 or to the circuit of scrubber 3 (the circuit consists in each case of scrubber sump, circulation pump, return line and at least one spray level). If a pre-washer is dispensed with and only one S02 scrubber is operated, the same applies to the addition of the compounds leading to an insoluble mercury compound or the adsorbent.
(Hierzu 2 Blatt Zeichnungen) (2 sheets of drawings)

Claims

Patentansprüche Claims
1. Verfahren zum Reinigen eines Schwefeldioxid, Quecksilber und ggf. andere Schadstoffe enthaltenden Abgases, bei dem das Abgas entstaubt und in mindestens einer Stufe mit einer calciumhaltigen Waschflüssigkeit gewaschen wird und bei dem das gebildete Calciumsulfit unter Zufuhr von Luft in Calciumsulfat (Gips) umgewandelt wird und danach calciumsulfathaltige Waschflüssigkeit abgezogen und aus der abgezogenen Waschflüssigkeit Gips abgetrennt wird, d a d u r c h g e k e n n z e i c h n e t , daß dem Abgas vor dem Waschen oder der Waschflüssigkeit selbst eine das Quecksilber in eine wasserunlösliche Verbindung überführende Chemikalie und/oder ein das Quecksilber adsorbierendes Adsorptionsmittel zugegeben wird und eine wasserunlösliche und sich in der ausgefällten Form von der Form der Gipskristalle unterscheidenden Verbindung oder das beladene Adsorptionsmittel bei der Abtrennung des Gipses von der abgezogenen Waschflüssigkeit mit dem Abwasser abgeführt wird.1. A method for cleaning an exhaust gas containing sulfur dioxide, mercury and possibly other pollutants, in which the exhaust gas is dedusted and washed in at least one stage with a calcium-containing washing liquid and in which the calcium sulfite formed is converted into calcium sulfate (gypsum) with the addition of air and thereafter calcium sulfate-containing washing liquid is removed and gypsum is removed from the removed washing liquid, characterized in that a chemical which converts the mercury into a water-insoluble compound and / or an adsorbent which adsorbs the mercury and a water-insoluble and itself is added to the exhaust gas before the washing or the washing liquid itself in the precipitated form differentiating the shape of the gypsum crystals or the loaded adsorbent is removed with the waste water when the gypsum is separated from the removed washing liquid.
2. Verfahren nach Anspruch 1, d a d u r c h g e k e n n z e i c h n e t , daß Alkalisulfidverbindungen, Selensulfidverbindungen und/oder Jod zum Aufbau wasserunlöslicher Quecksilberverbindungen eingesetzt werden.2. The method of claim 1, d a d u r c h g e k e n n z e i c h n e t that alkali sulfide compounds, selenium sulfide compounds and / or iodine are used to build up water-insoluble mercury compounds.
3. Verfahren nach Anspruch 1 oder 2 , d a d u r c h g e k e n n z e i c h n e t , daß als β Adsorptionsmittel körnige Adsorptionsmittel oder Gele eingesetzt werden.3. The method according to claim 1 or 2, characterized in that as β adsorbent granular adsorbent or gels are used.
4. Verfahren nach mindestens einem der Ansprüche 1 - 3, d a d u r c h g e k e n n z e i c h n e t , daß bei einer mehrstufigen Wäsche die Zugabe der zu der schwerlöslichen Quecksilberverbindung führenden Chemikalie oder das Adsorptionsmittel in das Abgas vor der ersten Waschstufe erfolgt.4. The method according to at least one of claims 1-3, d a d u r c h g e k e n n z e i c h n e t that in a multi-stage wash the addition of the chemical leading to the sparingly soluble mercury compound or the adsorbent into the exhaust gas takes place before the first wash stage.
5. Verfahren nach mindestens einem der Ansprüche 1 - 4, d a d u r c h g e k e n n z e i c h n e t , daß der Waschflüssigkeit der mindestens einen Waschstufe mindestens eine Chemikalie zur Verbesserung und/oder weiteren Quecksilberabscheidung der Ausfällung zugesetzt wird.5. The method according to at least one of claims 1-4, that the washing liquid of the at least one washing step is added with at least one chemical for improving and / or further mercury separation of the precipitate.
6. Verfahren nach mindestens einem der Ansprüche 1 - 5, d a d u r c h g e k e n n z e i c h n e t , daß die Abtrennung vom Gips unter gleichzeitiger Entwässerung des Gipses mittels einer Zyklonstation mit nachgeschaltetem Bandfilter oder mittels einer Zentrifuge erfolgt.6. The method according to at least one of claims 1-5, that the separation from the gypsum takes place with simultaneous dewatering of the gypsum by means of a cyclone station with a downstream band filter or by means of a centrifuge.
7. Verfahren nach mindestens einem der Ansprüche 1 - 6 , d a d u r c h g e k e n n z e i c h n e t , daß die Zugabe der zur schwerlöslichen Quecksilberverbindung führenden Chemikalie in das Abgas mit einer vorgegebenen Reaktionszeit vor Eintritt in die Waschstufe erfolgt. 7. The method according to at least one of claims 1-6, that the addition of the chemical leading to the sparingly soluble mercury compound into the exhaust gas is carried out with a predetermined reaction time before entering the washing stage.
PCT/EP1992/001074 1991-07-13 1992-05-15 Process for cleaning an exhaust gas containing sulphur dioxide and possibly other pollutants WO1993000983A1 (en)

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DEP4123258.5 1991-07-13
DE19914123258 DE4123258A1 (en) 1991-07-13 1991-07-13 METHOD FOR CLEANING A SULFUR DIOXIDE AND Possibly. OTHER EXHAUST GASES CONTAINING POLLUTANTS

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100366326C (en) * 2000-12-08 2008-02-06 奥托库姆普联合股份公司 Method for removing mercury from gas
US11319233B2 (en) 2018-08-17 2022-05-03 Steve Feeney Consulting, Llc Control of aqueous arsenic, selenium, mercury or other metals from flue gas

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DK170887B1 (en) * 1993-01-21 1996-03-04 Fls Miljoe A S Process and use of a plant for cleaning residual products from flue gas treatment plants
DE4326279A1 (en) * 1993-08-05 1995-02-16 Veba Kraftwerke Ruhr Process for separating off mercury from flue gas
SE502159C2 (en) * 1993-12-22 1995-09-04 Flaekt Ab Method and apparatus for making plaster of high purity
DE4437781A1 (en) * 1994-10-25 1996-05-02 Steinmueller Gmbh L & C Process for removing mercury from an exhaust gas containing mercury
DE4441090A1 (en) * 1994-11-18 1996-05-23 Steag Ag Method and device for cleaning combustion exhaust gases
DE19542065C2 (en) * 1995-11-13 1997-10-23 Steag Ag Method and device for cleaning combustion gases from combustion plants
DE19730909A1 (en) * 1997-07-18 1999-01-21 Babcock Anlagen Gmbh Decontamination of flue gas, particularly from refuse incinerators
DE19800726C1 (en) * 1998-01-12 1999-09-23 Metallgesellschaft Ag Elementary heavy metal, especially mercury, separation from flue gases or combustion gases from waste incineration plants
DE69906054T2 (en) * 1998-05-08 2004-01-29 Isca Man Ltd DEPOSITION OF MERCURY FROM SMOKE GASES
JP3711229B2 (en) 2000-06-30 2005-11-02 株式会社日本触媒 Waste liquid treatment method
DE102012214065A1 (en) 2012-08-08 2014-02-13 EnBW Energie Baden-Württemberg AG Method of removing mercury from flue gas in a wet scrubber
DE102015218462A1 (en) 2015-09-25 2017-03-30 EnBW Energie Baden-Württemberg AG Apparatus supplementation of wet scrubbers in coal-fired power stations for better and safer separation of mercury and its compounds
CN106241384B (en) * 2016-09-12 2019-03-19 中国电力工程顾问集团西南电力设计院有限公司 A kind of agstone air-transport system and control method

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3119749C2 (en) * 1981-05-18 1984-11-08 Steag Ag, 4300 Essen Process for the production of calcium sulfate hemihydrate from flue gas gypsum
DD236459A1 (en) * 1985-04-25 1986-06-11 Leipzig Chemieanlagen METHOD OF WET SOILING 2-SEPARATION FROM SMOKE OR EXHAUST GASES
DE2728692C2 (en) * 1976-08-19 1986-12-04 Dowa Mining Co. Ltd., Tokio/Tokyo Process for removing mercury-containing impurities from acid gases

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3827831A1 (en) * 1988-08-17 1990-02-22 Thyssen Industrie METHOD AND SYSTEM FOR THE TREATMENT OF WASTEWATER, IN PARTICULAR FROM THE FLUE GAS DESULFURATION
DE4032249C2 (en) * 1989-10-14 1998-09-24 Knauf Westdeutsche Gips Process for brightening flue gas gypsum

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2728692C2 (en) * 1976-08-19 1986-12-04 Dowa Mining Co. Ltd., Tokio/Tokyo Process for removing mercury-containing impurities from acid gases
DE3119749C2 (en) * 1981-05-18 1984-11-08 Steag Ag, 4300 Essen Process for the production of calcium sulfate hemihydrate from flue gas gypsum
DD236459A1 (en) * 1985-04-25 1986-06-11 Leipzig Chemieanlagen METHOD OF WET SOILING 2-SEPARATION FROM SMOKE OR EXHAUST GASES

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
Derwent Accession Nr. 78-791 16A, Questel Tele- systems (WPI), Derwent Publications Ltd., London, GB, *
Derwent Accession Nr. 80-782 05C, Questel Tele- systems (WPI), Derwent Publications Ltd., London GB, *
Patent Abstracts of Japan, unexamined applications, C Sektion, Band 11, Nr. 365, 27. November 1987, The Patent Office Japanese Government, *
Patent Abstracts of Japan, unexamined applications, C Sektion, Band 12, Nr. 37, 04. Februar 1988, The Patent Office Japanese Government, *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100366326C (en) * 2000-12-08 2008-02-06 奥托库姆普联合股份公司 Method for removing mercury from gas
US11319233B2 (en) 2018-08-17 2022-05-03 Steve Feeney Consulting, Llc Control of aqueous arsenic, selenium, mercury or other metals from flue gas

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