DE3411529A1 - Process for the dry purification of gases - Google Patents

Abstract

The invention relates to a process for the dry purification of gases, in particular for the reversible chemisorption of sulphur dioxide, and pollutants reacting in a related manner, from exhaust gases and flue gases. The process is likewise directed at the removal of hydrogen sulphide, and pollutants reacting in a related manner, from hot gases upstream of gas turbines and metallurgical and chemical plants, and from fresh hot utility gases in general. In this case, if desired, the absorbed material can then be fed to utilisation and the adsorbent material can be regenerated. The process according to the invention is characterised in that means are provided for inducing an intramolecular and/or intermolecular or otherwise continuously effected thermal process with diffuse distribution.

Description

Friedrich Erich Friday Hartmannstrasse 28 1000 Berlin 45

and / ■ ■ ^:

Dipl.-Ing. Paul Jordan, -, Alpsteinweg 7

7750 Constance

March 22, 1984

Process for dry cleaning of gases.,

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Description

The invention relates to a method for dry cleaning of gases, particularly for the purpose of chemoabsorption of sulfur dioxide and related reacting pollutants from exhaust gases and flue gases, but also to remove hydrogen sulfide and related reactants Pollutants from hot gases in front of gas turbines and before metallurgical and chemical plants, -anything from fresh, hot useful gases; in all cases, a subsequent use of the Absorbed and the regeneration of the known in ^ e-r Way through the gas moving absorbent can be connected.

The need for so-called desulphurization of power plant flue gases, the need in general for cleaning exhaust gases is now widely known. As for performing in dry, even for Regeneration or recovery of the absorbent is concerned with suitable technical processes this dry method evidently more and more desirable. Because the wet cleaning processes bring you up to the dry ones - for them, however, high There is hardly any experience - annoying disadvantages that are perceived more annoyingly from year to year with them: The huge ones Quantities of the resulting sludge (sludge quantities) find a landfill more and more difficult; what is more usable Jbaugips accrues, 'brings inadequate proceeds; the transport becomes unaffordable here and there; the large amount of wastewater creates trouble, problems, rising costs: and that you have to heat up the wet-washed chimney,

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robs the last aura of such technology.

-But also on the other hand, with the dry processes, is the current state of the art in no way to be rated as satisfactory, if only because it is much too young. He lets himself - at least for the present one Invention - read from:

1.) -German Disclosure Document 1 769 350, Int.Cl. Jj 01 d, 53/34 and 53 / H;

2.) "HANDELSBLATT" of February 15, 1984, No. 33, page 21: "'" Hot gas desulphurization with solid copper ", investigations of the TU Clausthal.

It should now be noted that the melt described in 1.) - as the absorbent - only works at 350 to 450 ° C, and the copper-containing pellets mentioned in 2.) as the absorbent only come into effect at a maximum of 750 ° C. _: - According to the knowledge and according to the laboratory measurements on which the present invention is based as its first beginning, at these low temperatures the possible success is far from being achieved. ; And it is even astonishing and worth investigating into the cause that at least 90 degrees desulphurisation could be achieved in Clausthal.

In contrast, the present invention assumes that 'for a substantial chemoabsorption a much higher temperature is necessary, especially in metals, for example in copper.

In fact, 19-10 A.SIEVERTS in of the magazine for electrochemistry, 16th volume, 1910, page 708 especially for those - like him

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it called it at that time - "gas solubility" of "sulfur dioxide in copper was correctly proven and graphically demonstrated that this gas solubility rises very steeply up to the melting point of copper at" 1083 C. and then continues to increase steadily (in a straight line) and very considerably. This is shown in the drawing in Fig. 1 for sulfur dioxide in copper, specifically in the temperature-dependent function, where-i is the absorption ratio-the V'h em ο absorption! -.- aäs χ milligrams SOp per 500 milligrams metallic Cu is shown to scale.

But Ibai's own experiments were additional phenomena gefunden.Zunächst had the physical conditions ^ aa ron A.SIEVERTS · measurements into the closer to reality physical conditions (flow, gas pressure u.dergl.) Are transformed '. Regardless of this, it turned out that even under the physical circumstances of the measurements of 1910 one cannot speak of "solubility" of the gas, but rather that a real chemical reaction must be assumed if one wants to advance in the matter. In terms of the bonding intensity between sulfur dioxide and copper, for example, one has to reckon with the order of magnitude that is present in those so-called "addition compounds" for which A.WERWER (Nobel Prize for Chemistry 1905) is of such a surprisingly great interest - certainly not wrongly - has shown (A.WERNER, Weuere views in the field of inorganic chemistry, Braunschweig (1909), page 31 ff.) strange bond between gas and solid or vaporous metal or metallic equivalent substance depends very clearly and extremely subtly and precisely on the mutual relationship of the molecular weights. (Incidentally, this also applies - confirming the matter - to the relationship with the formation of platinum hydrochloric acid, which A. Werner had tried in vain to clarify.)

All of these scientific ones, which are unusual for patent applications . Comments had to be added because it is not just about the "state of the art"

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nik "but reasonably well for the" going state of the science. "(It is the _r patent examination body to emphasize allowed what they can answer.) We live in the time of forest death und.des Contergans, our science dieweiien shines - and limps! —— ■ ■ '

In any case, higher temperatures are usually required for dry gas cleaning in order to advance in the technology of this field; and that generally applies to both the "exhaust gases, flue gases" and the "waste gases" (for gas turbines, etc. ) division Maintaining the walls of the reaction spaces, and also the effort involved in heating up the gas. This fundamental dilemma is countered according to the invention in a fundamental way that means for bringing about a more or less spontaneous intramolecular and / and a more or less spontaneous intermolecular Thermal energy for the reaction between gas and absorber, i.e. in the reaction space, which in and of itself normally already has a high temperature, are made available. This thermal energy is the direction of energy that the E χ ο thermal, - if maif-srine inner-molecular energy of course not with the word "ex'othermi The spontaneous inner and spontaneous intermolecular thermals are of a chemical nature and origin, and their purpose and purpose is to avoid an excessively high general temperature, the reaction chamber walls thermally so

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far as it is economical to discharge and yet the main reaction between the pollutant and the To move absorbents up in the thermally favorable area. .

According to the further invention, this chemical method can contribute to the advantages of a high temperature Avoidance of disadvantageous accompanying circumstances, also replaced by physical means and methodology be, for example, through the wall-friendly electrical high heating by means of shortwave. That offers itself especially when the_ absorbent ,, for example metallic copper, from lumpy or pellet-shaped Transport bodies is moved through the reaction chamber and out of it. Because such small pieces Transport bodies can be much more economical in Manufacture of thermally high-quality material and continuously use it as large-area walls subject to structural stress. It is within the scope of the invention if; in good distribution, for example in a grid over the vom to be cleaned gas cross section provided more or less small electrical flame arcs are without or with magnetic blowing of the flame arcs or arc. The electrodes or horns can be completely or partially burned off the pollutant absorbing material, e.g. copper, in finely divided or even vaporous form Deliver condition. According to the invention, in a manner known per se, for example by means of electrical self-induction elements (-Coils) must be provided for constant or periodic re-ignition, so that a

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Kind of "long-running" and more or less continuous work of the flame arcs takes place can preferably be operated with direct current.

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"It belongs within the scope of the invention if, instead of using electric flame arcs, such arcs are used Energy sources for thermal energy in diffuse distribution

-. or in a coarser distribution, the for example, like non-electric welding torches with hydrogen and oxygen or with hydrocarbons and oxygen or air or chlorine or the like.

· Provide heat. According to the invention, you can reduce-. Working in flue gas, for example, or oxidizing burning, for example with fresh gas Gas turbines should be set, the more detailed conditions from the literature, for example on welding technology can be taken. '

Regarding the electric flame arcs, reference is also made to the literature, in particular to the Book by M.PIRAM, "Elektrothermie", Berlin 1930 pointed out, in particular, the electrical generation and technical use of high temperatures has to the content.

At this point, as a precautionary measure, because: even a considerable outlay on equipment can at least be worthwhile if that The present method according to the invention for so-called peak operation in the event of smog peaks or for analog Situations of a known flue gas desulphurization process, possibly even a .wet process temporarily, if necessary automatically switched on, or in permanent operations or in other combinations that are justifiable from an engineering point of view or in the semi-technical or pilot execution of its technical development is used as an additional procedure.

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As a chemical induction agent a spontaneous intramolecular thermal of "involuntarily diffuse distribution can according to the invention serve entirely or partially graphite oxide (= graphitic acid.). This stuff and its for the invention Such an important thermal decomposition ability is extensively described in GMELINS Handbook of Inorganic Chemistry, 8th edition, part B, delivery 3t system ■ r. DJr. 14, Weinheim (1968). - In the present invention So it is about the thermal decomposition of the agent graphite oxide when it enters the already. hot reaction space, which will probably always be hot enough for dry desulphurisation processes. to trigger the spontaneous decomposition of the graphite oxide, since around 200 υ are sufficient for this.

In GMELIWS Handbook, however, a phenomenon of downright astonishing intensity is not described, the observation of which contributed considerably to the creation of the present invention: When the graphite oxide decomposes spontaneously, copper oxide or copper oxide that has been added is added as a freshly shiny metallic one Free of copper, namely subliming or evaporating, during the decomposition - based on the object of the invention - the asorbent for the noxious gas SO ₂ and thermal energy are spontaneously released. This is used according to the invention in every relationship. - It belongs within the scope of the invention if the graphite oxide with or without the .Beimgung the absorber precursor, which can be, for example, copper oxide, in a suitable mixture with

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A liquid medium is introduced into the hot reaction space, for example injected, which can make the transport and metering of the agent considerably easier - on the preparation of graphite-oxide-liquid mixtures, there are useful references in German Patent 933 829

Besides graphite oxide (= graphitic acid) can According to the invention, the following substances are used: J Sodium formate, other formates, nitrated carbon, nitrated coke, nitrated coal or mixtures of the aforementioned substances, either whole or partially ; and silicon compounds with a similar spontaneous decomposition character can also be used in whole or in part be applied. According to the invention, the absorbent itself is preferred in all cases can be a metal or an alloy or a metal compound. According to the further invention however, the absorbent can also be a substance that is one of the intermetallic compounds. Fre can the absorbent m a physical or chemical association with the means for the Thermie be located according to the invention.

"After the further invention, for the absorbent without or with the agent for the Thermal carrier or transport body, e.g. Jb. Pellets ^ are used that are wholly or partially made up of more or consist of less porous metal carbide and accordingly · = »: · ' be able to bring with them their own ability to reduce. Wach the further invention can then be a special one Be saved when it comes to absorbent

Sulfur dioxide .binding .and related to that of reacting pollutants.

For the sake of clarity and conciseness, it is intended to refer to descriptions of the dust and fluid filters and sluices, be it for them Collection of the reaction space after the puncture done leaving and starting the path to regeneration adsorbents plus Adsorbier tem-S.daubgut or bulk goods or the like, be it against contaminants Dust or the like. To be dispensed with because. Everything that is necessary about this has already been published in abundance is. It goes without saying that the apparatus installation of the method according to the invention should be carried out after proven rules of engineering plant construction must be carried out.

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Claims (8)

Claims' 1. Process for dry cleaning of gases, especially for reversible chemoabsorption of ■ Sulfur dioxide and related pollutants from exhaust gases and flue gases, but also for the removal of hydrogen sulfide and related reacting pollutants from hot gases in front of gas turbines and in front of metallurgical and chemical Plants, in general, from fresh hot useful gases, in all cases a subsequent use of the absorbed and the regeneration of the can be connected in a known manner through the gas moving absorbents, characterized in that Means for bringing about a more or less spontaneous intramolecular and / or such a thing intermolecular and / or otherwise, then optionally also brought continuously T h e r m i e of extremely diffuse distribution are provided ·. v *% _. 2. The method according to claim 1, - characterized in that the means of a chemical nature and the absorbent are admixed or combined with it in such a way that they put this in the gas to be cleaned into the status nascendi .., which is achieved through chemical reduction properties of the agent can be brought about, and that for this purpose the absorbent in the form of its oxide or the like to its EPO - COPY Task, which he then just recently reduc- * 7 adorned shape. 3. The method according to claim 1. Or 2, - ' thereby geke η η ζ ei ch net, that -ß '■ as an agent completely or partially graphitic acid (= graphite oxide), sodium formate or other formate, nitrated carbon, nitrated coke, nitrated "coal or mixtures of the aforementioned substances applied" T ^ are or completely or partially silicon compounds with a similar spontaneous decomposition character, .which in all .Fall the absorbent itself preferably a metal or a metal compound or a Alloy or an intermetallic compound can be. '. " 4. The method according to claim 1 to 3, ■ characterized in that the "absorbent in a known manner copper oxide, copper oxide or another copper compound or the metal is copper itself or an alloy or intermetallic compound thereof, but in one physical or chemical association with the Means for the thermie is located. 5. Procedure according to. Claim 1 to 4, characterized in that instead of the known more or less porous carrier or transport body for the absorbent, e.g. instead of ceramic pellets, such bodies or pellets are used, which consist entirely or partially of more or less porous metal carbide and EPO - COPY can accordingly bring their own ability to reduce with them. 6. A method according to claim 5, characterized g ~ ek ennzeichnet that the absorbent is saved when using reducing Met ^ allcarbid, if it is sulfur bond and to the reacting of related contaminants. 7 »Method according to claim 1, characterized in that the thermal energy is applied entirely or partially electrically, namely by shortwave 'and / or by electrical Flame arcs in good distribution, which according to known electrical circuit principles for constant reignition, So can be set as a "long-term hit" and apart from the thermal finely distributed copper burn-off deliver as absorbent * 8. The method according to any one of claims 1 to 7, characterized in that it for so-called peak operation for smog peaks or for situations analogous to a known flue gas desulphurisation process, possibly even a wet process temporarily, · if necessary, operated automatically switched on. EPO - COPY