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WO1996004202A1 - Procede et installation de recuperation et de traitement du dioxyde de soufre dans les gaz d'echappement - Google Patents

Procede et installation de recuperation et de traitement du dioxyde de soufre dans les gaz d'echappement Download PDF

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Publication number
WO1996004202A1
WO1996004202A1 PCT/FI1995/000410 FI9500410W WO9604202A1 WO 1996004202 A1 WO1996004202 A1 WO 1996004202A1 FI 9500410 W FI9500410 W FI 9500410W WO 9604202 A1 WO9604202 A1 WO 9604202A1
Authority
WO
WIPO (PCT)
Prior art keywords
liquid container
sulphur dioxide
equipment
washer part
flow line
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.)
Ceased
Application number
PCT/FI1995/000410
Other languages
English (en)
Inventor
Viljo JÄRVENPÄÄ
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.)
Wiser Oy
Original Assignee
Wiser Oy
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 Wiser Oy filed Critical Wiser Oy
Priority to EP95944007A priority Critical patent/EP0796221A1/fr
Priority to AU30793/95A priority patent/AU3079395A/en
Publication of WO1996004202A1 publication Critical patent/WO1996004202A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/69—Sulfur trioxide; Sulfuric acid
    • C01B17/74—Preparation
    • C01B17/76—Preparation by contact processes
    • C01B17/775—Liquid phase contacting processes or wet catalysis processes
    • 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
    • B01D53/507—Sulfur oxides by treating the gases with other liquids

Definitions

  • the invention concerns a method for recovery and treatment of sulphur dioxide contained in exhaust gases.
  • the invention concerns an equipment for recovery and treatment of sulphur dioxide contained in exhaust gases.
  • the commonest device for cleaning of flue gases is an electric filter, which usually removes the dust from flue gases to a sufficient extent, but which allows free passage for the gaseous components of the flue gases.
  • an electric filter usually removes the dust from flue gases to a sufficient extent, but which allows free passage for the gaseous components of the flue gases.
  • the neutralizing agent needed in the dry-separation process is fed either directly into the combustion or to among the hot flue gases.
  • the temperature of the flue gases is lowered, whereby the sulphur dioxide (SO 2 ) and the moisture and the caustic lime react with each other and form calcium sulphite powder (CaSO 3 ), which is then separated by means of dry filtering.
  • SO 2 sulphur dioxide
  • CaSO 3 calcium sulphite powder
  • milk of lime is atomized into the flue gases as the neutralizing agent.
  • the supply of milk of lime must be large enough so that the sulphur dioxide can be neutralized reliably and, at the same time, the temperature of the flue gases be lowered sufficiently for dry filtering.
  • the result of this process is a dry powder which contains, besides the solids contained in the flue gases, also calcium sulphite that has been formed. True enough, part of the calcium sulphite may be oxidized to calcium sulphate, i.e. gypsum, but the main part of the product of neutralization consists of calcium sulphite powder.
  • the drawbacks of the semi-dry separation process are, in principle, the same as those of the dry separation process, i.e. disproportionately high consumption of pure neutralizing agent, but additionally also the fact that the calcium sulphite (CaSO 3 ) formed as a powder is a material that has no compression strength. This results from the "hairiness" of calcium sulphite, i.e. calcium sulphite consists of pin-covered granules which cannot be compressed into a compact mix. Thus, the use of the calcium sulphite formed, for example, as filling soil for foundations of buildings or roads is out of the question. In principle, the calcium sulphite formed is a material suitable for skiing pistes only.
  • the best process known so far for removal of sulphur is the so-called wet- ashing process, in which the flue/combustion gases are washed with a neutralizing washing liquid.
  • the sulphur dioxide dissolves from the flue gases into the washing liquid and makes the washing liquid acid.
  • the acid washing liquid is then neutralized by means of a suitable chemical, most commonly with limestone (CaCO 3 ) or milk of lime, i.e. calcium hydroxide (Ca(OH) 2 ).
  • limestone limestone
  • Ca(OH) 2 calcium hydroxide
  • the object of the present invention is to provide a method and an equipment in which the numerous drawbacks present in the prior-art solutions are avoided.
  • the flue gases are passed as a flow into the washer part, and the sulphur dioxide (SO 2 ) contained in the flue gases is dissolved into the washing liquid passed into the washer part,
  • the equipment in accordance with the invention is characterized in that the equip ⁇ ment includes
  • a washer part into which the flue gases are passed along a first flow line and the washing liquid along a second flow line and/or along a third flow line, in which connection the sulphur dioxide contained in the flue gases is dissolved into the washing liquid that has been passed into the washer part,
  • a fourth flow line for passing the mixture that has been dissolved into the washing liquid and that contains sulphur dioxide (SO 2 ) from the washer part into the liquid container
  • a liquid container in which the mixture that contains sulphur dioxide is oxidized at a pressure of free choice, by means of a gas, preferably air, that is placed in the liquid container and that contains oxygen (O 2 ), into sulphur trioxide (SO 3 ), which forms sulphuric acid (H 2 SO 4 ) together with the water present in the liquid container.
  • a gas preferably air
  • the present invention it has been realized to oxidize the sulphur dioxide in connection with the washing directly into sulphuric acid.
  • the sulphur dioxide contained in the flue gases is dissolved into the washing liquid, which is oxygenated/aerated inten ⁇ sively, whereby the sulphur dioxide dissolved in the washing liquid is oxidized into sulphur trioxide (SO 2 + V2O1 - > SO 3 ), whi . .
  • sulphuric acid H ⁇
  • SO 2 sulphur diox
  • washing liquid can be passed into the washer part either from the liquid container in which sulphuric acid is formed or from a separate washing-liquid duct or from both.
  • the treatment of the acid mixture that flows out may be either concentration or neutralization with a suitable lime, which lime is now, however, of secondary importance and can be even impure lime.
  • a suitable lime which lime is now, however, of secondary importance and can be even impure lime.
  • the result is a chemical product of reasonably low cost, concentrated sulphuric acid, or gypsum that is suitable for filling soil and raw-material.
  • the neutraliz ⁇ ation taking place in the process of the present invention is directly stoichiometric without any extra consumption of neutralizing agent.
  • the equipment in accordance with the invention is denoted generally with the reference numeral 10.
  • the flue gases that contain sulphur dioxide are passed into the washer part 11 as a flow 13.
  • washing liquid is passed, for example, from a circulation water pump 15, which sucks washing liquid out of the washing-liquid container 12.
  • additional washing liquid such as additional water, can be passed along the flow line 16 as a washing liquid of its own, which replaces any amount of washing liquid that may evaporate and the acid solution that flows out along the discharge line 22.
  • the washing-liquid container 12 there is a stirrer shaft 18, at whose end there is a stirrer-disperser 19, in which case the air/oxygen mixture which is fed out of the feed line 20, preferably, for example, through the hollow stirrer shaft 18 is passed and dispersed by means of the stirrer/disperser 19 into the washing liquid present in the washing-liquid container 12, whereby the sulphur dioxide dissolved in the washing liquid is oxidized into sulphur trioxide.
  • a motor 21 is fitted to rotate the stirrer shaft 18. From the washer. part 11, the washing liquid into which the sulphur dioxide dissolved from the flue gases has been dissolved flows along the flow line 17 into the washing-liquid container 12.
  • the circulation water pump 15 is preferably such that it sucks the air that flows along the flow line 23. Owing to this, additional air is supplied into the oxygenous liquid in the washing-liquid/water container, which air is dissolved into the washing liquid in the flow duct 14 after the circulation water pump 15 under pressure, preferably of an order of about 1...10 bar, before the liquid enters into the washer part 11. Owing to this, the liquid that flows into the washer part 11 is highly oxygenous and, at the same time, takes care of the circumstance that the sulphur dioxide that has been dissolved into the washing liquid, the liquid that contains sulphuric acid and water, is oxidized under pressure ever more completely into sulphur trioxide.
  • oxidization of sulphur dioxide takes place both in the flow duct/pipe 14 placed after the circulation water pump 15 and passing into the washer part 11, in the washer part 11, and in the washing-liquid container 12.
  • oxidization takes place with the aid of the addition of air/oxygen supplied along the feed line 20 and with the aid of the stirrer 18 and the stirrer/disperser 19 just at a very low positive pressure.
  • the bottom part of the washing-liquid container 12 is provided with a removal of deposit 24 for the removal of the deposit that arises as a result of solid matter that may be contained in the flue gases and as a result of precipitation resulting from probable oxidization.
  • the process of oxidization in accordance with the present invention can also be carried out in a number of different ways and by means of different solutions of equipment, but an essential feature is oxidization of the sulphur dioxide in the liquid/water, at a pressure which can be chosen freely in principle, in the washing- liquid container 12, and the ultimate oxidization under pressure in the pipe/duct 14 after the circulation water pump 15.
  • the addition of air/ oxygen can also be carried out in a way differing from the embodiment shown in the figure in the drawing, but even then the final result is the desired one.
  • the supply of air/oxygen into the circulation water pump 15 or into the pressurized flow duct or pipe 14 after the pump can be carried out in a number of different ways, but the major part or even all of the sulphur dioxide is oxidized in the pressurized state 14.
  • the washing-liquid container 12 is kept rich in oxygen just otherwise.
  • the process of the present invention is elastic and simple.
  • the washer part 11 may be a washer part known from the prior art. It is the essential idea that the sulphur dioxide is dissolved into the washing liquid as completely as possible, which liquid contains a substantial amount of sulphuric acid, as a result of concentration, according to the basic realization of the invention.
  • a suitable concentration of acid is, for example, a 50 % sulphuric acid, which is taken out as the flow 22, this concentration being the capacity of dissolution of sulphur dioxide by sulphuric acid and being almost equal to the corresponding capacity of dissolution of sulphur dioxide by pure water.
  • the oxidizing gas passed along the line 20 it is possible to use air or air enriched with oxygen, but also pure oxygen gas can be used.
  • the latter mode is just an expensive mode of oxidizing.

Landscapes

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

Abstract

Procédé et installation (10) de récupération et de traitement du dioxide de soufre (SO2) contenu dans les gaz d'échappement. Selon ce procédé, les gaz de rejet sont admis sous forme de flux dans la partie de lavage (11), et le dioxide de soufre (SO2) contenu dans ces gaz de rejet est dissous dans le liquide de lavage lors de son passage dans cette partie de lavage (11). Le mélange contenant le dioxide de soufre (SO2) et ayant été dissous dans le liquide de lavage est acheminé par une conduite (17) dans une cuve à liquide (12). Le mélange envoyé dans la cuve (12) et contenant du dioxide de soufre (SO2) est oxydé, à une pression librement choisie, à l'aide d'un gaz, de préférence l'air, qui est admis dans la cuve (12) et contenant de l'oxygène (O2), pour obtenir du trioxide de soufre (SO3), lequel forme de l'acide sulfurique (H2O4) en présence de l'eau contenue dans la cuve (12).
PCT/FI1995/000410 1994-08-02 1995-08-01 Procede et installation de recuperation et de traitement du dioxyde de soufre dans les gaz d'echappement Ceased WO1996004202A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP95944007A EP0796221A1 (fr) 1994-08-02 1995-08-01 Procede et installation de recuperation et de traitement du dioxyde de soufre dans les gaz d'echappement
AU30793/95A AU3079395A (en) 1994-08-02 1995-08-01 Method and equipment for recovery and treatment of sulphur dioxide contained in exhaust gases

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI943589A FI943589L (fi) 1994-08-02 1994-08-02 Poistokaasun rikkidioksidin pesu rikkihapoksi
FI943589 1994-08-02

Publications (1)

Publication Number Publication Date
WO1996004202A1 true WO1996004202A1 (fr) 1996-02-15

Family

ID=8541153

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1995/000410 Ceased WO1996004202A1 (fr) 1994-08-02 1995-08-01 Procede et installation de recuperation et de traitement du dioxyde de soufre dans les gaz d'echappement

Country Status (5)

Country Link
EP (1) EP0796221A1 (fr)
AU (1) AU3079395A (fr)
CA (1) CA2196531A1 (fr)
FI (1) FI943589L (fr)
WO (1) WO1996004202A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998009713A1 (fr) * 1996-09-03 1998-03-12 Monsanto Company Elimination et recuperation selective de l'anhydride sulfureux dans des effluents gazeux au moyen de solvants organophosphores

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4156712A (en) * 1976-02-28 1979-05-29 Chiyada Chemical Engineering & Construction Co., Ltd. Gas-liquid contacting method
EP0484222A1 (fr) * 1990-10-29 1992-05-06 Socrematic Procédé de traitement de gaz contenant du dioxyde de soufre
WO1993020917A1 (fr) * 1992-04-21 1993-10-28 Wiser Oy Procede et systeme de traitement de liquides

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4156712A (en) * 1976-02-28 1979-05-29 Chiyada Chemical Engineering & Construction Co., Ltd. Gas-liquid contacting method
EP0484222A1 (fr) * 1990-10-29 1992-05-06 Socrematic Procédé de traitement de gaz contenant du dioxyde de soufre
WO1993020917A1 (fr) * 1992-04-21 1993-10-28 Wiser Oy Procede et systeme de traitement de liquides

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998009713A1 (fr) * 1996-09-03 1998-03-12 Monsanto Company Elimination et recuperation selective de l'anhydride sulfureux dans des effluents gazeux au moyen de solvants organophosphores
US5851265A (en) * 1996-09-03 1998-12-22 Monsanto Company Selective removal and recovery of sulfur dioxide from effluent gases using organic phosphorous solvents

Also Published As

Publication number Publication date
FI943589A0 (fi) 1994-08-02
FI943589A7 (fi) 1996-02-03
FI943589L (fi) 1996-02-03
CA2196531A1 (fr) 1996-02-15
AU3079395A (en) 1996-03-04
EP0796221A1 (fr) 1997-09-24

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