CA2237098A1 - Plant and process for thermal decomposition, melting and vitrification and for recovering substances from waste and residues of the most widely varying kinds - Google Patents

Abstract

The invention relates to a plant and process for the thermal decomposition, melting and vitrification and the recovery of substances from waste and residues of the most widely varying kinds at high temperature in a closed reaction chamber with apertures for feeding in the material to be processed and reaction substances and for removing the gaseous and fluid reaction products. Material to be processed is inserted into the reactor by feed devices (6) and thermally treated by burners (3). The melt can be agitated by special gasifying units (10). Besides being mixed by vertically blowing units, the melt can be caused to circulate by tangentially arranged units. The gas flow is regulated via valves operated by a programmable gas regulator (14). With suitable melts, the rotation can be supported by electromagnetic agitators (11) as desired. The rotation results in a uniform distribution of the material on the melt. Vertical gasification also ensures that the melts is thoroughly mixed. Both effects promote the formation of free surfaces and the intensive contact of the material with the hot, high-energy heat sources. This results in an efficient reaction. The flue gases formed are removed via the extractor for prior art subsequent treatment. Material to be processed can also be fed in beneath the melt surface. As soon as processing is completed, controlled casting is performed via the casting system with the closure device and the casting device.

Description

05fOl~P, 10: 3~ F.~;~ 212 ~8728B~ CA 02237098Rl99D o~jRoRER

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PL NT hND.PROCESS FOR T~ERMA~ DECOMPOSITION, MELTING AND
VI~ RIFI~ATION ~D FOR RECO~ERIN~ SUBSTANCES FROM WAS~E AND
RX IDUES OY THE MOST WI~LY YA~YIN~ KINDS

The invention relates to a plant and a pro~ess for thermal de.o~position, ~lting and vitrification and for recovering su st~n5~ fro~ waste and r-sidues of the ~ost widely varying ki ds a~ high t~mpcr~tures in a closed reaction chamber with op nings ~or deliverin~ stoc~ ~o be trQated and rea~tion su ~tahces and for diseharging the gaseous or liquid reaction pr duct~.
M~ny industrial wast~s pre5ent problems in disposal and re ycling. Often, ~hey contain valua~le ~ubs~ncPs that can be re.overed only with great difficulty and by expensive methods. To en ble ef~ctive, ~c~o~ic~l processing, v-r3atile pl~nts and pr cesses are nee~ed.
Ther~al plants ~or treating wastes and recovering valuable BU stances are relatively old. ~arbage incinerating plants with gr te ~irlng, rotary tubular furnaces or pyrolysis ~urnaces are kn wn. Also known ~re ~elt baths ~salts or met~ls) for de omposing wastes ~nd rendering them in~rt. For recoveri~g metal su st~ncQs~ induction ~urnace6, ~rc furn~ces, plasma furnaces ~n~
ot ers are in uso. Rot~ting hearths (horizontal, vertical) ~i~h va ious pouring devices are al50 ~nown. These plants are usually hi hly suita~le for treating complex mixtures and accumulations of ~u ~tan~es. But these known systems are not in a posi~ion to ha dl~ complex wastes so that in one stop, organic components can ~e vapori~ed, inorganic sub~ances can be ~ound into A vitreous or cr ~talline slag, and ~etal s~bs~A~c~ can be precipitated out for re ov~ry. In moct cases, in the known p~oc~ , prob~matic .
re idue~ are produced, such ~s filt~r dust, sludge, or ashes. The ob eGt of the inven~ion is to convert the most various kinds of 05J01.~08 10:~3 F~ 21~ ~&728~ CA 02i370s8 ~998-05-o~BR ~004 wa te into valuab~e substances and unproble~atic sub~tance~ by me. n~ of ~ khermal process, so that:
- organic cQ~ronents are thermally d~compooed:
- inorganic ~esidues are sel~ctively bound into ~ vit~e~us or cry~talline slag:
- m~tal residue~ and reaction produ~ts are recovered.
According to the inv~nticn, this is attained by ~mploying a cl sed-he~rth rea~cr, which in it~ upper part has one or more h~ t sources comprising hot gas~s. Ele~ents for blowing in gases an du ~ are dispose~ such that the delivery of the substance can be ~ffect~d selectiYely verti~lly and tangentially. The process ga es are deli~ered in a known m~nner to appropriate treatmen~
~t ge~ ouch a$ filter~, condensers, washers, catalytically active st ge~, etc. The molten products can also be ~elivered to a ~tage fo further tre,~tment. Heating of th~ h-arth i8 effected with a a~ hot and high--n~rgy a h~at ~ource as possible, which enables hi~ h d~gro~s of deco~po~itio~, high ~e~al yields, and high slag qu lity. ~Y~m~les o~ such heat sourc~s ar- oxygen burner~, arc~, ~n~: plasma ~urners. To attain high throughputc, low energy co ~ump~ion and a compl~te reaction, c~re is takeh to assure good di tribu~ion and mixing of th4 molt~n stock~ ~cording to the in ention, this is e~fecte~ by ~eans of progra~med delivery of ga es to the melt through vertic~lly and t~nqentially ~ispos~d n~ ~les, or by the action of elect~ neti~ fields, or ~y a co: bination of the two methods. The reaction gases ar~ d~liver~d th ough ~n indu~d-draft blower to the post-tre~tment stages, ~h ch are known per se~ Th~ syste~ operates under c~ntrolled pr;~ur- within a predetermined rang~.
The ad~ntage~ of th~ plant described here are as ~ollows:
- ~ecAus~ o~ the great flexi~ility in ~er~ ~f cha~ging a~d pr ~S control, highly he~erog~neous kinds of waste and residues ca b~ handled:

05~01~8 10:~ F~ 212 ~&728B~ CA 02237098~Rl9~98 oq5Ro8R;ER

- Th~ variou~ c:harging mod~s, Which can also be e~nployed si;ult~n~o~ly if n~P~, allow waste streams ~o be optimally co;bin~d, 80 that ~hey can b~ pro~ssed into va~uabl~ sU~stances an~ unproblematic residues.
- The motion of the melt leads to a ~uperfi~ial di tribution of ~he stock f~d on top of i~, and as a result the de ired reactions (pyroly~is, reduction, oxidation, etc.) take pl ~e quickly and e~fici-ntly (thi~-film e~fect).
- Th~ controll~d ~otion of the melt ~nabl~s op~im~l mixing in ~ way that is adapted to the stock: thi~ is not the case with v~ tic~lly disposed rotating hearth furn~c~s, for exa~ple.
- Because o~ th~ fin~ ~istrib~tion of the stock that is th r~by attained, the exposed surfac~s are increased in size, thus le.din~ to a v~ry efficient r~action.
- Wastes in ~he ~orm of dust can be fed in underneath ~he me t, which minimizQs the development of dust in the exhaust gas.
- Reactive gase~ such as oxygen, hydrogen, water vaEwr, et . can be blown dir~ctly into the melt through th~ vertically an~ tang~ntially di~posed n~zzles~ in order to achieve ~esired re ctions~
~ xamplos of fi~lds in whi~h the plant and the process can be u$ed are as ~ollows:

Co~bustib~ h~zardou~ waste in solid or sludge form:

~ ia a vat charging dQvice, a feed worm, or other feeding ~e hode, ~uch w~s~es c~n be f-d onto the surface of a melt of in~rganic compon~nts, which has b~Qn put in place be~orehand.
Ac ing as the vat charging device is a horizontally disposed gr pp~r, which feed~ the vat in a horizontal pO~itiOh through an op ning into thQ reacto~ cha~b~r. A v~t opening device {such as an ac-tyl~ne tor~h~ is mount4d where the vdt enters th~ reactor~

05~01~8 10:33 FA~ 212 88728~ STRIKER AND STRIRER ~oo~
CA 02237098 l998-05-08 Th grip~er can be ~o~ed axially an~ can also be rotated. A~ ~
re ult, the va~ is cut apa~t by th~ v~t opening devi~e, so that th contents, along with the r-mnant~ of the va~, are distributed ~v nly onto the ~elt.
Good distribution of t~e ~aterial is assured by t~e ~o~ion of ~he ~ath. Onc~ a ~rtain bath l~vel is l~c~e~, the ~elt is po r~d o~. The flue gases are oxidized without residue in a po ~co~bu~tion chamber. In the flue gas $crubber that foll~ws, th ~mi8siohB are re~ucs' to below the applicable li~nits. Th-~e idueu produced in the flue gas scru~bing ~re fed back into the re ctor after ~h~ wat~r has been sepzlrated off.

Resi~ue~ and waste i~ dust for~, ouch as filter dust that co t~ins metal:

To av~rt du~t ~evelop~ent, thes~ residu~s ~re fed i~
un erneath the pre-placQd melt ~ein~ blown in pneumatically, for in tance). In the reducing atmosph~re tha~ is established in the re ction chamber, the redu~ible metal oxides, such a~ CuO, FeaJ
~n , PbO, Nio, etc. are reduced to metals and precipitated in th~
fo m of liquid ~tal out of the pre-plac~d ~elt, or are exhausted in vapor form ~long with the ~lu- gas. Thi~ OpQ~ation is re~nforced by a ~uitable combin~tion of electroma~netic ~otion and ga:sing. The ~olatile metals ~such as zinc) can be recovered from th flue gas ~y ~uitabl~ con~-nsation stages. Once a certain ~elt vo ume is att~i~P~, the two ph~ , that is, the metal portion and th non~e~al portion of th~ melt, are poured off ~eparately.

Mixed waste that contains m~tal:

Nixed waste containing metal, su~h a~ us~d cataly~t~ f~om th ch~io~l indu-~try, can be fed into the rea~tor. The organic 05~01~8 10: 34 F.~2L 212 88728~ CA 02237098EP~lgA98 oq~; Ro8R;ER

co;ponent3 are ~t:lQ~O~ed, and the recoYered me~als ar~ ~nriched in a ~other ~elt. The inorgani~ residues ar bound in~o a vi reou~ or cry~talline matrix.

Ga~eous waste an~ rQ~idues, such as toxic gases;

The~e g~ses can be f~ ~ire~tly through th~ gassing op nings in~o the m~lt or into the heat source, a~ a result o~
which ~specially effi~ient decomposition can be attained.
This plant is al~o e~pecially suitable for p~o~essing ra ioactiv~ waste i~o products ~uited ~o~ ultimate disposal.

~ escription of ~he plant:

Fig~. l and 2 show a plant ~ccor~ing t~ the invention in se.tion and in outline, ~espectively.
M~terial to be proctssed is introduced, to~e~her with ad itive subs~anc-s if nec*c~Ary~ throu~h th~ charging device 6 in o the re~ctor and is melted by the ~orches or burners 3. The m~lt B aan ~e set into motion ~y ths ga~sing elements 10. Along wi h mixing by th~ eloments th~t blow vertical~y, rotation of the m~it can be attai~ed by m~ans of the tangentially disposed el.~ents. To that end, the ~elt motion is first initiate~ by me . ns o~ periodic gas pul~es. As soon as the m~lt motion ha~
st rt~d, it i~ maintained by means of continuous gassing. ~h~
ro ~tional ~p-e~ can ~e ~egulated by means of the quan~i~y of gas bl wn in. The ~as flow is regulated via valves, which are tri~g~r~d by a ~ro~..~abl~ gas regul~tor 14. For a giv~n ~elt, th rotation can b~ ~electively reinforc~d by means of the el ~tro~agnatic agitator ~lsments 11. All of these ~lement~ are in egrated into ~h~ lower p~rt 2 of th~ r-actor. As soon as the me t i~ rotati~g, the a~tual charging op4r~tion begins, through 05~01~ 10:34 F~ 212 ~8728B~ CA 022370IgKERgAN~ o95RoIl~ER l~boo8 th charging de~i~e 6. Becau~e of the rotation, an even di tri~ution of the m~terial on the melt is achievQd. The ve,tical gafisi~g mor-ove~ leads to int~n~i~e ~ixing of the melt.
Bo'h e~ects promote the formatian of expo~-d surfaoe~ and the in enciv~ contact ~f the material with th~ not, high-enQrgy heat oo rce~. As a result, An e~ri~ient rQaation is achieved. Through th flue ga~ ~nt 13, which i~ int~grated into ~he upper part 1 of th reactor, the flue gases produced are scrubbed, in post-tr atmQnt operations known p~r se. To oxidize ~he flu~ gas even in the r~actor, oxygen is blown in through the nozzle 7. By means of the ~eal 5 and by monitoring the openings, the wrong air is pr ~nt~d from entering the system. Material to be pro~essed can be introduced not only through the charging de~ice ~, but also un erneath the melt surface vi~ thQ inlQt g. Once the pro~o~ing ha b~-n completed, the controlled pouring off is done, via the po rinq ~ystem having the stopper device 4 and the sp~ut 12.

Claims (25)

Claims:

1. A plant for thermal decomposition, melting and vitrification and for recovering substances from waste and residues of the most widely varying kinds at high temperatures in a closed reaction chamber with openings for delivering stock to be treated and gases and for discharging the gaseous or liquid reaction products, characterized in that in the upper part of the reaction tank, one or more heat sources comprising hot gases are disposed such that they act largely perpendicularly on the stock, and that in the bottom part of the tank, elements for blowing in gases and dust are disposed, and are disposed such that the delivery of the substance can be effected selectively between vertically and tangentially.

2. The plant of claim 1, characterized in that the gas delivery elements are distributed spatially in groups, and these groups can be triggered separately in accordance with a program.

3. The plant of claim 1, characterized in that the heat sources (3) are directly or indirectly operated plasma burners.

4. The plant of claim 1, characterized in that the heat sources (3) are carbon arcs.

5. The plant of claim 1, characterized in that the heat sources (3) are burners for liquid and gaseous fuels.

6. The plant of claims 1-5, characterized in that the heat sources (3) are arranged movably, such that they can sweep over largely the entire surface of the reaction tank.

7. The plant of claim 1, characterized in that the reaction tank (1/2) is round.

8. The plant of claim 1, characterized in that the reaction tank (1/2) is polygonal.

9. The plant of claim 1, characterized in that the reaction tank is constructed in two parts, comprising an upper part (1) and a lower part (2).

10. The plant of claim 1, characterized in that the opening (12) for discharging the liquid is disposed at the lowermost point of the bottom.

11. The plant of claim 1, characterized in that the melt is moved by electromagnetic agitators (11).

12. The plant of claim 1, characterized in that it is equipped with an inductive support heater.

13. A process for thermal decomposition, melting and vitrification and for recovering substances from waste and residues of the most widely varying kinds at high temperatures in a closed reaction chamber with openings 6, 9, 13) for delivering stock to be treated and gases and for discharging the gaseous or liquid reaction products, of claims 1-12, characterized in that a melt of inorganic material is put in place beforehand, and the stock is added; and that heat is supplied from above and gas is blown in from below.

14. The process of one of claims 13-22, characterized in that the stock is sluiced into the melt.

15. The process of claim 13, characterized in that the gas is blown in by programmed control (14) in such a way that the melt is moved, and a defined mixing or melt motion between the melt and the stock is attained.

16. The process of claim 13, characterized in that from outside, an electromagnetic field is applied to the reactor and controlled in such a way that good mixing between the melt and the stock is attained.

17. The process of claim 13, characterized in that from outside, an electromagnetic field is applied to the reactor and controlled in such a way that the melt is set into a rotary motion.

18. The process of claim 13, characterized in that with the gas, powdered stock is added in metered fashion in such a way that in is blown into the region of influence of the gaseous heat source.

19. The process of claim 13, characterized in that the gas is reactive.

20. The process of claim 13, characterized in that the plasma gas contains reactable components.

21. The process of claim 13, characterized in that the thermal treatment is effected under controlled pressure.

22. The process of one of claims 13-22, characterized in that oxygen is delivered to the reaction chamber.

23. The process of claim 13, characterized in that the complete oxidation of the products of decomposition takes place in the reactor.

24. The process of claim 13, characterized in that complex wa~tes comprising organic, inorganic and metal-containing substances are treated in one step in such a way that organic components are vaporized, inorganic components are bound into a me~t, and the metals are recovered.

25. The process of one of claims 13-22, characterized in that the wastes are introduced into closed vats via a sluice, and that the vat is open and the contents are delivered to the process in controlled fashion