DE3515707C2 - - Google Patents

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Publication number
DE3515707C2
DE3515707C2 DE3515707A DE3515707A DE3515707C2 DE 3515707 C2 DE3515707 C2 DE 3515707C2 DE 3515707 A DE3515707 A DE 3515707A DE 3515707 A DE3515707 A DE 3515707A DE 3515707 C2 DE3515707 C2 DE 3515707C2
Authority
DE
Germany
Prior art keywords
stage
washing
washing liquid
iron
wash
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
DE3515707A
Other languages
German (de)
Other versions
DE3515707A1 (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 DE19853515707 priority Critical patent/DE3515707A1/en
Priority to EP86902811A priority patent/EP0217945A1/en
Priority to PCT/EP1986/000207 priority patent/WO1986005709A1/en
Publication of DE3515707A1 publication Critical patent/DE3515707A1/en
Application granted granted Critical
Publication of DE3515707C2 publication Critical patent/DE3515707C2/de
Granted legal-status Critical Current

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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
    • B01D53/68—Halogens or halogen compounds
    • 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
    • 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

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  • 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)
  • Treatment Of Water By Oxidation Or Reduction (AREA)
  • Gas Separation By Absorption (AREA)

Description

Die Erfindung bezieht sich auf ein Verfahren zur Entfernung von HCl, SO₂ und NOx aus Rauchgasen nach dem Oberbegriff des Patentanspruchs 1.The invention relates to a method for removing HCl, SO₂ and NO x from flue gases according to the preamble of claim 1.

In der DE-PS 35 14 407 ist ein derartiges Verfahren beschrieben. Bei diesem bekannten Verfahren wird in einer einer NOx- Waschstufe vorgesetzten Waschstufe das SO₂ mit Kalkstein oder Kalkhydrat so weit ausgewaschen, daß sich im Rauchgas vor der letzten Waschstufe ein stöchiometrisches SO₂/NOx-Verhältnis von 2 : 1 einstellt, bei dem sich gleichzeitig SO₂ und NOx gut auswaschen lassen. Gleichzeitig wird zur Verstärkung des Eisen- II-Komplexes, d. h. zur Verhinderung der Oxidation von Fe++ zu Fe+++, Natriumdithionit der Waschflüssigkeit zugesetzt und zur Eigenverwässerung des Redox-Potentials im negativen Bereich Natriumsulfit und/oder Pyrosulfit angewandt, wobei das Natriumsulfit auf mehr als 20 g/l in der Waschflüssigkeit eingestellt wird. Such a method is described in DE-PS 35 14 407. 1 sets, in which at the same time: washing stage superior washing stage the SO₂ with limestone or hydrated lime as far washed out, that in the flue gas prior to the last washing stage a stoichiometric SO₂ / NOx ratio of 2 - in this known method in one of a NO x is Wash out SO₂ and NO x well. At the same time, sodium dithionite is added to the washing liquid to reinforce the iron-II complex, ie to prevent the oxidation of Fe ++ to Fe +++ , and sodium sulfite and / or pyrosulfite is used for self-watering the redox potential in the negative region, the sodium sulfite is set to more than 20 g / l in the washing liquid.

Ausgehend von dem vorstehend geschilderten Stand der Technik liegt der Erfindung die Aufgabe zugrunde, das gattungsgemäße Verfahren derart weiterzubilden, daß der Verbrauch an Reduktionsmittel herabgesetzt und damit das gesamte Verfahren kostengünstiger durchgeführt werden kann. Es hat sich heraus­ gestellt, daß nicht nur der Anteil an Natriumsulfit im Waschwasser die ausschlaggebende Rolle für die NOx-Abscheidung bildet. Der grundsätzliche Gedanke, nämlich der Waschflüssigkeit ein Reduktionsmittel, z. B. Dithionit, zuzusetzen, und zur Mas­ kierung von Eisen-III und zur Verhinderung der Oxidation von Eisen-II zu Eisen-III außerdem Weinsäure zuzusetzen, wird bei­ behalten. Der Natriumsulfatgehalt in der Waschlösung, der durch Reduktion des von der Eisen-II-Chelatlösung aufgenommenen Stickstoffmonoxids zu elementarem Stickstoff und Natriumsulfat mittels Natriumsulfit wird bis zur Sättigungsgrenze angereichert. Hierdurch nimmt das zugegebene Reduktionsmittel in wesentlich geringerem Umfang an der Oxidation teil und bleibt infolgedessen aktiv erhalten. Somit kann bei einer Rohgas­ belastung von 1600 mg NO/Nm³ auf 100 mg NO/Nm³ mit weniger als 0,5 g Natriumdithionit-Zugabe pro 1 Waschflüssigkeit bei einer Waschflüssigkeitsmenge von 3 l/Nm³ Rohgas eine befriedigende Auswaschung erzielt werden.Starting from the prior art described above, the invention is based on the object of developing the generic method in such a way that the consumption of reducing agent is reduced and the entire method can thus be carried out more cost-effectively. It has been found that not only the proportion of sodium sulfite in the wash water forms the decisive role for the NO x separation. The basic idea, namely the washing liquid is a reducing agent, e.g. B. dithionite, and to add masking to iron III and to prevent the oxidation of iron II to iron III, also to add tartaric acid, is retained. The sodium sulfate content in the wash solution, which is reduced by reducing the nitrogen monoxide taken up by the iron II chelate solution to elemental nitrogen and sodium sulfate by means of sodium sulfite, is increased to the saturation limit. As a result, the added reducing agent takes part in the oxidation to a much lesser extent and is consequently actively retained. Thus, with a raw gas load of 1600 mg NO / Nm³ to 100 mg NO / Nm³ with less than 0.5 g sodium dithionite addition per 1 washing liquid with a washing liquid quantity of 3 l / Nm³ raw gas a satisfactory washout can be achieved.

Durch die erfindungsgemäßen Maßnahmen ist eine Rauchgasreinigung von SO₂ und NOx wesentlich preiswerter als beim Stand der Technik zu gestalten.Through the measures according to the invention, flue gas cleaning of SO₂ and NO x is much cheaper than in the prior art.

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 zweiten Waschstufe, der eine mit CaCO₃, Ca(OH)₂ und einer Carbonsäure betriebene erste Waschstufe vorgeschaltet ist, bei dem die aus der zweiten Waschstufe 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 der ersten Waschstufe 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 Wasch­ flüssigkeit und das im Filter aus dem Gips herausgelöste Wasser in die zweite Waschstufe 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 Pro­ zeßwasserkreislauf zurückgeführt wird, nach Patent 35 14 407, dadurch gekennzeichnet, daß die Waschflüssigkeit in der zweiten Waschstufe so lange mit dem Rohgas kontaktiert wird, bis sich eine Konzentration des sich bildenden Natriumsulfats von 200 g/l in der Waschlösung einstellt.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 of a second washing stage, which is preceded by a first wash stage operated with CaCO₃, Ca (OH) ₂ and a carboxylic acid, in which the wash liquid removed from the second wash stage as wastewater for washing liquid treatment is mixed in a container with hydrated lime, then fed to a dewatering stage and with a low residual moisture content Oxidation stage into which air or oxygen is introduced and in which the pH value is lowered by the washing liquid from the first washing stage and / or by sulfuric acid, the wet gypsum formed in the oxidation stage being passed through a filter with a residual moisture of < 8% is removed and the in the dewatering stage released washing liquid and the water released from the gypsum in the filter are recycled into the second washing stage, and the washing water for rinsing the gypsum is passed into an iron precipitation stage in which iron hydrate is precipitated by raising the pH value and that Excess wastewater is passed from the iron precipitation stage to an EDTA precipitation stage, in which the EDTA is precipitated by adding H₂SO₄ and is returned to the process water circuit, according to Patent 35 14 407, characterized in that the washing liquid in the second washing stage with the raw gas is contacted until a concentration of the sodium sulfate formed of 200 g / l is established in the washing solution.
DE19853515707 1985-04-06 1985-05-02 Single-and/or multiple-stage HCl-, SO2- and NOx-scrubbing process for flue gas purification, preferably downstream of fossil-fuel power stations Granted DE3515707A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
DE19853515707 DE3515707A1 (en) 1985-05-02 1985-05-02 Single-and/or multiple-stage HCl-, SO2- and NOx-scrubbing process for flue gas purification, preferably downstream of fossil-fuel power stations
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
DE19853515707 DE3515707A1 (en) 1985-05-02 1985-05-02 Single-and/or multiple-stage HCl-, SO2- and NOx-scrubbing process for flue gas purification, preferably downstream of fossil-fuel power stations

Publications (2)

Publication Number Publication Date
DE3515707A1 DE3515707A1 (en) 1986-11-06
DE3515707C2 true DE3515707C2 (en) 1992-12-03

Family

ID=6269586

Family Applications (1)

Application Number Title Priority Date Filing Date
DE19853515707 Granted DE3515707A1 (en) 1985-04-06 1985-05-02 Single-and/or multiple-stage HCl-, SO2- and NOx-scrubbing process for flue gas purification, preferably downstream of fossil-fuel power stations

Country Status (1)

Country Link
DE (1) DE3515707A1 (en)

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5096478A (en) * 1973-12-27 1975-07-31

Also Published As

Publication number Publication date
DE3515707A1 (en) 1986-11-06

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