DE3523354C2 - - Google Patents

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Publication number
DE3523354C2
DE3523354C2 DE3523354A DE3523354A DE3523354C2 DE 3523354 C2 DE3523354 C2 DE 3523354C2 DE 3523354 A DE3523354 A DE 3523354A DE 3523354 A DE3523354 A DE 3523354A DE 3523354 C2 DE3523354 C2 DE 3523354C2
Authority
DE
Germany
Prior art keywords
stage
washing
washing liquid
iron
scrubber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
DE3523354A
Other languages
German (de)
Other versions
DE3523354A1 (en
Inventor
Heinz Dipl.-Ing. Hoelter
Heinrich Dipl.-Ing. 4390 Gladbeck De Igelbuescher
Heinrich Ing.(Grad.) 4600 Dortmund De Gresch
Heribert Dipl.-Ing. 4390 Gladbeck De Dewert
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to DE19853523354 priority Critical patent/DE3523354A1/en
Priority to EP86902811A priority patent/EP0217945A1/en
Priority to PCT/EP1986/000207 priority patent/WO1986005709A1/en
Publication of DE3523354A1 publication Critical patent/DE3523354A1/en
Application granted granted Critical
Publication of DE3523354C2 publication Critical patent/DE3523354C2/de
Granted legal-status Critical Current

Links

Classifications

    • 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
    • B01D53/60—Simultaneously removing sulfur oxides and nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/68—Halogens or halogen compounds
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Landscapes

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

Description

Die Erfindung bezieht sich auf ein Verfahren zur Entfernung von HCl, SO₂ und NOx aus Rauchgasen unter Verwendung einer Ethylendiamintetraessigsäure (EDTA)- und/oder Nitrilotriessigsäure (NTA)-Eisenchelat, NaOH, eine Carbonsäure und Natriumdithionit und/oder Natriumsulfit bzw. -pyrosulfit enthaltenden Waschflüssigkeit einer zweiten Waschstufe, der eine mit CaCO₃, Ca(OH)₂ und einer Carbonsäure betriebene erste Waschstufe vorgeschaltet ist, bei dem die aus dem Wäscher als Abwasser entnommene Waschflüssigkeit zur Waschflüssigkeitsaufbereitung in einem Behälter mit Kalkhydrat gemischt wird, dann einer Entwässerungsstufe zugeführt und mit einer geringen Restfeuchte einer Oxidationsstufe, in die Luft oder Sauerstoff eingeleitet wird und in der die pH-Wert-Absenkung durch die Waschflüssigkeit des Wäschers und/oder durch Schwefelsäure erfolgt, übergeben wird, wobei der in der Oxidationsstufe gebildete nasse Gips über einen Filter mit einer Restfeuchte von <8% ausgeschleust wird und die in der Entwässerungsstufe freigesetzte Waschflüssigkeit und das im Filter aus dem Gips herausgelöste Wasser in den Wäscher recyclisiert werden, und wobei das Waschwasser zur Spülung des Gipses in eine Eisen-Fällstufe geleitet wird, in der durch pH-Wert-Absenkung Eisenhydrat gefällt wird und das aus der Eisen-Fällstufe überschüssige Abwasser einer EDTA-Fällstufe übergeben wird, in der durch Zugabe von H₂SO₄ das EDTA gefällt und in den Prozeßwasserkreislauf zurückgeführt wird.The invention relates to a method for removing HCl, SO₂ and NO x from flue gases using an ethylenediaminetetraacetic acid (EDTA) - and / or nitrilotriacetic acid (NTA) -iron chelate, NaOH, a carboxylic acid and sodium dithionite and / or sodium sulfite or pyrosulfite containing washing liquid of a second washing stage, which is preceded by a first washing stage operated with CaCO₃, Ca (OH) ₂ and a carboxylic acid, in which the washing liquid removed from the scrubber as wastewater is mixed with hydrated lime in a container for washing liquid treatment, then fed to a dewatering stage and with a low residual moisture to an oxidation stage into which air or oxygen is introduced and in which the pH is lowered by the washing liquid of the scrubber and / or by sulfuric acid, the wet gypsum formed in the oxidation stage being passed through a filter a residual moisture content of <8% t and the washing liquid released in the dewatering stage and the water dissolved out of the gypsum in the filter are recycled into the scrubber, and the washing water for rinsing the gypsum is passed into an iron precipitation stage in which iron hydrate is precipitated by lowering the pH is and the excess wastewater from the iron precipitation stage is transferred to an EDTA precipitation stage, in which the EDTA is precipitated by adding H₂SO₄ and is returned to the process water cycle.

Ein derartiges Verfahren ist aus dem deutschen Patent 35 14 407 bekannt.Such a method is from the German patent 35 14 407 known.

Der Erfindung liegt die Aufgabe zugrunde, bei dem gattungsgemäßen Verfahren den Eisenchelatkomplex in der Waschflüssigkeit gegen Sauerstoffangriff zu stabilisieren.The invention has for its object in the generic Process the iron chelate complex in the washing liquid stabilize against oxygen attack.

Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß in die Waschflüssigkeit der zweiten Waschstufe zur Stabilisierung des Eisenchelatkomplexes Kohlendioxid zugegeben wird. Durch das zugesetzte Kohlendioxid wird der Eisenchelatkomplex wirksam gegen einen Sauerstoffangriff stabilisiert.This object is achieved in that in the Washing liquid of the second washing stage to stabilize Iron chelate carbon dioxide is added. By the added carbon dioxide, the iron chelate complex becomes effective stabilized against an oxygen attack.

Claims (1)

Verfahren zur Entfernung von HCl, SO₂ und NOx aus Rauchgasen unter Verwendung einer Ethylendiamintetraessigsäure (EDTA)- und/oder Nitrilotriessigsäure (NTA)-Eisenchelat, NaOH, eine Carbonsäure und Natriumdithionit und/oder Natriumsulfit bzw. -pyrosulfit enthaltenden Waschflüssigkeit einer Waschstufe 2, der eine mit CaCO₃, Ca(OH)₂ und einer Carbonsäure betriebene Waschstufe 1 vorgeschaltet ist, bei dem
die aus dem Wäscher 2 als Abwasser entnommene Waschflüssigkeit zur Waschflüssigkeitsaufbereitung in einem Behälter mit Kalkhydrat gemischt wird,
dann einer Entwässerungsstufe zugeführt und mit einer geringen Restfeuchte einer Oxidationsstufe, in die Luft oder Sauerstoff eingeleitet wird und in der die pH-Wert-Absenkung durch die Waschflüssigkeit des Wäschers 1 und/oder durch Schwefelsäure erfolgt, übergeben wird,
wobei der in der Oxidationsstufe gebildete nasse Gips über einen Filter mit einer Restfeuchte von <8% ausgeschleust wird und die in der Entwässerungsstufe freigesetzte Waschflüssigkeit und das im Filter aus dem Gips herausgelöste Wasser in den Wäscher recyclisiert werden, und
wobei das Waschwasser zur Spülung des Gipses in eine Eisen-Fällstufe geleitet wird, in der durch pH-Wert-Anhebung Eisenhydrat gefällt wird und das aus der Eisen-Fällstufe überschüssige Abwasser einer EDTA-Fällstufe übergeben wird, in der durch Zugabe von H₂SO₄ das EDTA gefällt und in den Prozeßwasserkreislauf zurückgeführt wird, nach Patent 35 14 407, dadurch gekennzeichnet, daß in die Waschflüssigkeit der zweiten Waschstufe zur Stabilisierung des Eisenchelatkomplexes Kohlendioxid zugegeben wird.Process for the removal of HCl, SO₂ and NO x from flue gases using an ethylenediaminetetraacetic acid (EDTA) - and / or nitrilotriacetic acid (NTA) -iron chelate, NaOH, a carboxylic acid and sodium dithionite and / or washing liquid containing sodium sulfite or pyrosulfite in a washing stage 2, which is preceded by a washing stage 1 operated with CaCO₃, Ca (OH) ₂ and a carboxylic acid, in which
the washing liquid removed from the scrubber 2 as waste water for washing liquid treatment is mixed in a container with hydrated lime,
then fed to a dewatering stage and with a low residual moisture to an oxidation stage into which air or oxygen is introduced and in which the pH value is lowered by the washing liquid of the scrubber 1 and / or by sulfuric acid,
wherein the wet gypsum formed in the oxidation stage is discharged through a filter with a residual moisture of <8% and the washing liquid released in the dewatering stage and the water released from the gypsum in the filter are recycled into the scrubber, and
wherein the washing water for rinsing the gypsum is passed into an iron precipitation stage, in which iron hydrate is precipitated by raising the pH and the excess wastewater from the iron precipitation stage is transferred to an EDTA precipitation stage in which the EDTA is added by adding H₂SO₄ precipitated and returned to the process water circuit, according to patent 35 14 407, characterized in that carbon dioxide is added to the washing liquid of the second washing stage to stabilize the iron chelate complex.
DE19853523354 1985-04-06 1985-06-29 Simultaneous SO2 and NOx scrubbing downstream of combustion plants with simultaneous stabilization of the iron salt complexes in the scrubbing solution Granted DE3523354A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
DE19853523354 DE3523354A1 (en) 1985-06-29 1985-06-29 Simultaneous SO2 and NOx scrubbing downstream of combustion plants with simultaneous stabilization of the iron salt complexes in the scrubbing solution
EP86902811A EP0217945A1 (en) 1985-04-06 1986-04-05 Process for the cleansing of fumes
PCT/EP1986/000207 WO1986005709A1 (en) 1985-04-06 1986-04-05 Process for the cleansing of fumes

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19853523354 DE3523354A1 (en) 1985-06-29 1985-06-29 Simultaneous SO2 and NOx scrubbing downstream of combustion plants with simultaneous stabilization of the iron salt complexes in the scrubbing solution

Publications (2)

Publication Number Publication Date
DE3523354A1 DE3523354A1 (en) 1987-01-08
DE3523354C2 true DE3523354C2 (en) 1992-05-07

Family

ID=6274568

Family Applications (1)

Application Number Title Priority Date Filing Date
DE19853523354 Granted DE3523354A1 (en) 1985-04-06 1985-06-29 Simultaneous SO2 and NOx scrubbing downstream of combustion plants with simultaneous stabilization of the iron salt complexes in the scrubbing solution

Country Status (1)

Country Link
DE (1) DE3523354A1 (en)

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1251900B (en) * 1967-10-12 Heinrich Koppers Gesellschaft mit beschrankter Haftung, Essen Process for removing nitrogen compounds from gases
JPS5210659B2 (en) * 1973-04-09 1977-03-25
GB1482643A (en) * 1973-10-31 1977-08-10 Kureha Chemical Ind Co Ltd Method for removing oxides of nitrogen from a gas
JPS5096478A (en) * 1973-12-27 1975-07-31
DE2554584B2 (en) * 1974-12-28 1979-02-22 Chisso Corp., Osaka Process for regenerating an aqueous solution of an iron chelate complex and a sulfite used for the absorptive removal of nitrogen oxides and sulfur oxides from exhaust gases

Also Published As

Publication number Publication date
DE3523354A1 (en) 1987-01-08

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