AU781344B2 - Process for disposing of halogenated and non-halogenated waste substances - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): PAC HOLDING S.A.

Invention Title: PROCESS FOR DISPOSING OF HALOGENATED AND NON- HALOGENATED WASTE SUBSTANCES The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 PROCESS FOR DISPOSING OF HALOGENATED AND NON-HALOGENATED WASTE SUBSTANCES The present invention relates to a process for disposing of halogenated and non-halogenated waste substances.

Substituted, in particular halogenated hydrocarbons, such as are present for example in carbon tetrachloride, chloroform, methylene chloride, tetra- and trichloroethylene, tetrachloroethane, PCB etc., but also in PVC or polyvinylidene chloride, are a more or less problematical toxic or special waste following use, which has to be disposed of.

Substances with a strong toxic effect on the environment and man, such as halogenated compounds, in particular polyhalogenated substances such as PCBs or TCDD/TCDF (dioxins/furans) cannot be automatically recycled and have to be disposed of in an environmentally friendly manner.

The disposal takes place either by dumping or by incineration on the high seas or else on land in hightemperature furnaces with an excess of air.

The energy requirement is in many cases not inconsiderable, since not only do the substances to be disposed of have to be vaporised and heated to the required decomposition temperature, but enormous amounts of air also have to be heated up. In so doing either, as with incineration on the high seas, pollution of the atmosphere and the risk of acid rain have to be allowed for, or extremely expensive plants are required for keeping the air clean.

There is known from DE-A-33 13 889 a process or an apparatus for disposing of toxic and special waste, in which the toxic waste substances are mixed with an electrically conductive material, in particular in the form of iron powder and/or coke, and are brought in an induction furnace to the decomposition temperature of the H:\suzafet\eep\Speci\P46273.1 SPECIdoc 24/06/02 3 toxic and/or special waste to be eliminated.

US-A-4 435 379 discloses a process for decomposing chlorinated hydrocarbons with metal oxides with the aim of converting all carbon atoms into carbon monoxide. It is a question here of providing elemental chlorine for the conversion of hydrogen groups into HC1.

The overall ratio of chlorine to hydrogen groups must be at least 1 1 here, in order to be able to produce metal chloride.

US-A-4 587 116 discloses a similar process, in which nitrogen-containing waste substances can also be disposed of. The heating likewise takes place from the outside and not from the inside.

US-A-4 451 907 discloses a process for disposing of chlorinated organic compounds. The chlorinated organic compounds are initially vaporised in a salt melting furnace, and then fed into a reactor. In the reactor the chlorinated, organic compounds are heated to between 800 and 1200 this in the presence of aluminium oxide and reactive carbon monoxide, and consequently decomposed.

Nitrogen is used as carrier gas in order to feed the vaporised chlorinated organic compounds from the salt melting furnace to the reactor.

EP-0 306 540 discloses a process for recovering energy from substituted hydrocarbons such as are present e.g. as CC1 4

CHCI

3

C

2

H

2 C1 4 PCB, PVC, polyvinylidene chloride etc. in pure or bound form. In this process the waste material is decomposed thermally in an inductively heated reactor in the presence of a barely treatable metal oxide and an electrically conductive material, for example electrode coke or electrographite, and in contact with water vapour at temperatures of between 800 and 1 100 A portion of the metal oxide that corresponds to the chloride content of the waste materials is there converted into volatile metal chloride. A portion of the liberated carbon is converted into carbon monoxide and the portion of the carbon not reacting on the metal oxide is converted H:\suzanet\Keep\Speci\P46273.1 SPECI.doc 24/06/02 31/03 '05 THU 16:29 FAX 61 3 9243 8333 GRIFFITH HACK oo005 -4to water gas (CO H 2 with the aid of a stoichiometric amount of water vapour.

It is a preferred object of the present invention to develop a process which makes it possible to dispose of various halogenated and non-halogenated carboncontaining waste materials in an environmentally friendly manner.

According to the present invention there is provided a process for disposing of halogenated and nonhalogenated carbon containing waste materials in which the halogenated and non-halogenated waste materials are reacted with a metal oxide selected from TiO 2 SiO2, CaO, Fe203 or a mixture thereof with the exclusion of oxygen at temperatures of 8000C to 11000C, wherein hydrogen is produced instead of hydrogen chloride at the end of the process when hydrogen atoms are present in said waste materials.

The process described here can be used for the environmentally neutral recycling of halogenated and nonhalogenated waste materials.

The volume of the wastes used is largely reduced, so that as few residues as possible remain and as large a quantity as possible of metals/metal compounds is obtained. As positive an energy balance as possible is aimed at during the reaction.

In a preferred embodiment of the process, carbon-containing haloqenated waste materials are reacted.

Furthermore the reactor can also be supplied with carbon in the form of graphite and/or coal.

Various metal-oxide containing waste materials, such as silicon-containing residues from the metal-working industry, filter dusts, flue ashes, wind-blown sands, waste dumps, galvanic sludges, slags, slate residues etc., can also serve as reactants. Simple quartz, which consists about 98% of silicon dioxide (SiO2), is the simplest possible material which can be use for the conversion.

All of the above-mentioned materials are H:\mr:PA g\Fety\5;e:\t S(91( 02AM nldtF.Pag:.doc 31/03205 COMS ID No: SBMI-01184873 Received by IP Australia: Time 15:41 Date 2005-03-31 31/03 '05 THU 16:30 FAX 61 3 9243 8333 GIFT AK~ 0 GRIFFITH HACK (a 006 -4acharacteriseci by the fact that they contain a relatively COMS ID No: SBMI-01 184873 Received by IP Australia: Time 15:41 Date 2005-03-31 5 high content of halogenatable metal oxides (CaO, Si0 2 Ti02, Fe20 3 etc.).

This has the resultant advantage that materials containing metal oxides not treatable with economic agents to date now acquire a useful application.

Solvents such as carbon tetrachloride, chloroform, methylene chloride, tetra- and trichloroethylene, tetrachloroethane, coolants or refrigerants, PCB, pesticides, fungicides and herbicides, halogenated plastics such as PVC can be used as halogenated waste materials.

A portion of the metal oxide that corresponds to the chlorine content of the waste materials is converted into metal chloride by the above-mentioned process.

Ecologically and economically useful metal chlorides are obtained, wherein silicon and titanium tetrachloride (SiC1 4 TiC1 4 represent particularly preferred products.

Other materials such as spent oils, lubricants, fats, paints, dyes, tars, waxes, plastics, coolants and solvents, brake fluid or similar non-halogenated substances and materials can also be disposed of.

The reaction or conversion products preferably formed thermodynamically under these process parameters are hydrogen (H 2 which primarily occurs in gaseous form, together with smaller volumes in percentage terms of methane (CH 4 The formation of environmentally dangerous or environmentally polluting, gaseous substances such as carbon monoxide as well as the carbon dioxide (C0 2 known as a so-called greenhouse gas, is, under the preferred reaction conditions, negligibly small. Only at temperatures above 1100'C can CO or CO 2 be formed by chemical decomposition processes.

The conversion takes place in a fluidised bed reactor. The latter can be constructed either from special ceramics, silicon carbide (SiC) or specially alloyed steels.

H:\suzannet\Keep\Speci\P46273.1 SPECIdoc 24/06/02 6 The reactor can be brought to the required operating temperatures either by the use of electric heating elements heating half-shells) or by the use of an induction heater. The temperatures required for the conversion lie in the range from 800 0 C to 1100 0 C. The reaction itself takes place with the exclusion of oxygen.

Carbon dioxide (CO 2 is used as the fluidising gas.

The halogenated compounds are decomposed into their simplest constituents by the high temperatures. In the case of chlorinated hydrocarbons, hydrogen chloride, hydrogen, alkanes and chlorine gas are formed. The chlorine gas and the hydrogen chloride serve as chlorinating agents for the metal oxide-containing products or wastes. Products of this chlorinating reaction are the thermodynamically preferred metal chlorides.

In addition to the chlorides, hydrogen and carbon monoxide are formed, which can be used as a synthesis gas either for the obtaining of electrical energy or for other chemical syntheses, for example the methanol synthesis.

2-H 2 CO- CH 3

OH

Reaction Equation 1 The carbon dioxide (C02) used as the fluidising gas is converted completely to carbon monoxide (CO) by reaction with the carbon of the decomposed hydrocarbons and by an additional coal or graphite charge in the top part of the reactor.

The so-called BOUDOUARD reaction is referred to in this context: C0 2 +C Reaction Equation 2 The formation of environmentally harmful compounds such as dioxins, furans or e.g. phosgene (COC1 2 H:\suzaet\Keep\Speci\P462?3.1 SPECI.doc 24/06/02 7 is extremely improbable under the prevailing reaction conditions.

All the halogenated metal compounds produced are present initially in gaseous form. Depending on the starting material, solid, i.e. crystalline metal compounds can be obtained by cooling to room temperature, or else liquid metal compounds by condensation at low temperatures.

The degree of purity of these compounds is around 96% and can be further improved e.g. by a fractionating distillation, also called rectification.

Various embodiments of the invention will now be described below by means of the attached figures, where Fig. 1 shows a diagram of the plant for disposing of halogenated waste materials.

In the diagrammatic flow-chart of the process, as shown in Fig. 1, a feed line 1 for the halogenated waste materials, a feed line 2 for metal oxide-containing products, and a line 3 for the discharge of unconverted materials 3 can be seen. A fluidising gas (C0 2 is blown into the fluidised bed reactor 5 via a feed unit 4.

The reactor 5 is heated by means of a reactor heater 6 to a temperature of between 800'C and 1100'C, so that a reaction between the halogenated waste materials and the metal oxide-containing materials takes place in the reactor. The products formed are separated in a solids trap 7, and the solid metal chlorides formed, in particular FeCI 3 are discharged via a line 8. The remaining gases are purified by an activated carbon filter 9 and then compressed by a fan 10. The gases are then cooled in a cooling tank 12, which comprises a coolant inlet 11 and a coolant outlet 13, so that the remaining metal chlorides are separated out. SiC1 4 is mainly involved here.

The gases are then fed to a condenser 15 and subjected to an alkaline gas scrubbing in a gas scrubbing column 16. The column 16 possesses a circulating pump 17 H:\suzanet\Keep\Seci\P46273.1 SPECIdoc 24/06/02 8 for the scrubbing fluid. The remaining synthesis gas, a mixture of CO and H 2 is discharged through the line 18 in the upper part of the gas scrubbing column 16.

Application example i: Disposal of hydrocarbon- (HC) or halogenated hydrocarbon-containing (HHC) wastes in the presence of calcium oxide The various feedstocks, such as inter alia oils, fats, PCBs, CFCs, solvents or similar are conveyed via a metering device, e.g. an eccentric screw pump, into the reaction zone. There a first thermal cleavage of the feedstocks into short-chain hydrocarbons takes place very rapidly. The residence time of the feedstocks or that of the cleavage products obtained is determined by the height of the reaction zone.

As a rule a virtually quantitative breakdown into substantially hydrogen and methane takes place, wherein the volume ratio of hydrogen to methane lies clearly on the side of the hydrogen. Since the melting point of calcium oxide (CaO) is around 2500'C, substantial amounts of synthesised calcium compounds do not have to be allowed for.

If on the other hand halogenated feedstocks, in particular chlorinated materials, are caused to react, a reaction between the calcium oxide and the halogen atoms of the feedstocks then occurs.

In the main calcium chloride (CaCI 2 is formed as the reaction product, which remains in the reactor as slag or melt. The following reaction equation (reaction equation 1) takes account of all the main products which are formed during the disposal or recycling of a halogenated hydrocarbon. The individual products have been calculated thermodynamically and attested experimentally.

2CaO+4C H 2aClq+2CO+CH 4 +5C+8H, Reaction equation 9 H:\suzannet\Keep\Speci\P46273 .1 SPECI.doc 24/06/02 In addition to this reaction, carbon in the form of fine soot particles is also discharged out of the reactor.

The separation from the remaining gaseous constituents hydrogen and methane, or hydrogen and carbon monoxide is carried out by gravity separators, such as a high-capacity cyclone.

The gases cleaned in this way can in the interests of safety also be passed through activated carbon filters. Should foreign constituents still be contained in the process gas, the latter can be removed either by targeted condensation or by a gas scrubbing.

Finally, there remains as a rule only one synthesis gas, consisting of carbon monoxide, methane and hydrogen, which can be used for many different technical applications, e.g. energy recovery or use for chemical *syntheses (methanol synthesis) In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further o features in various embodiments of the invention.

It is to be understood that, if any prior art oo publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

H:\marieag\Keep\Speci\48916 02AmendedPages.doc 2/02/05

Claims (39)

1. Process for dispos: halogenated carbon-containinc waste materials are reacted x from Ti02, SiO2, CaO, Fe20 3 or exclusion of oxygen at tempel wherein hydrogen is produced at the end of the process whc in said waste materials.

2. that

3. that Process according t carbon is added during t Process according t graphite and/or coal is .ng of halogenated and non- waste materials, wherein the Fith a metal oxide selected a mixture thereof with the atures of 800°C to 1100 0 C, instead of hydrogen chloride n hydrogen atoms are present o claim 1, characterised in he process. o claim 2, characterised in used as carbon. o any one of the preceding solvents, coolants or ,fungicides, herbicides re used as halogenated waste o claim 4, characterized in trachloride, chloroform, d trichloroethylene or

4. Process according t claims, characterised in that refrigerants, PCB, pesticides and/or halogenated plastics a materials.

Process according t that the solvent is carbon te methylene chloride, tetra- an tetrachloroethane.

6. Process according t that the halogenated plastic

7. Process according t claims, characterised in that that corresponds to the chlor materials is converted into m, D claim 4, characterized in Ls PVC. D any one of the preceding a portion of the metal oxide Lne content of the waste tal chloride.

Process according t any one of claims i to 7, H: %5.r-1a~JEthe,\spcc±%,fl')16 t2ArcnsdF4'.j. doc a 3/c COMS ID No: SBMI-01184873 Received by IP Australia: Time 15:41 Date 2005-03-31 31/03 '05 THU 16:30 FAX 61 3 9243 8333 GRFIHAC GRIFFITH HACK characterised in that spent oils, lubricants, fats, paints, dyes, tars, waxes, plastics, coolants and solvents, brake fluid or similar non-halogenated substances and materials and mixtures thereof are used as non-halogenated waste materials.

9. The process according to any one of claims 1 to 8, wherein a first feed line feeds in the halogenated waste material to a reactor and a second line feeds in a product containing metal oxides to said reactor.

The process according to claim 9, wherein said product containing metal oxides is fed to the reactor in granulated form with a mean grain size of 3-8 mm.

11. The process according to claim 9 or 10, wherein said product containing metal oxides is slate.

12. The process according to claim 11, wherein the slate is introduced into the reactor apart from perchloroethylene as the halogenated waste material which is also introduced into the reactor.

13. A process for disposing of halogenated and non- halogenated waste materials, comprising: chemically reacting in A reaction the waste materials with a product containing metal oxides, wherein the metal oxides that are playing an active part in the reaction are at least one of Tib 2 3i0 2 CaD and Fe 2 0 3 the reaction being carried out with the exclusion of oxygen at temperatures of 800'C, to 1100'C in a reactor, wherein hydrogen is produced instead of hydrogen chloride at the end of the pr~ocess when hydrogen atoms are present in said waste materials.

14. T-he process according to claim 13, wherein a CP~sa,\A~ltOz~ont1dI~ea~ac41/O3,'V5 COMS 1D No: SBMI-01184873 Received by IP Australia: Time (I-Pm) 15:41 Date 2005-03-31 31/03 '05 THI 16:31 FAX 61 3 9243 8333 GRIFFITH HACK 01oio -12- first feed line feeds in halogenated waste material to a reactor and a second line feeds in the product containing metal oxides to said reactor.

15. The process according to claim 13 or 14, wherein said product containing metal oxides is fed in granulated form with a mean grain size of 3-8 mm.

16. The process according to any one of claims 13 to 15, wherein said product containing metal oxides is slate.

17. The process according to claim 16 wherein ground slate is introduced into a reactor apart from perchloroethylene as the halogenated waste material which is also introduced into the reactor.

18. A process for disposing of halogenated and non- halogenated carbon-containing waste materials, comprising: reacting the waste material with metal-oxide containing products with an exclusion of oxygen at temperatures of 800'C to 1100'C, and wherein carbon dioxide is added during the process, wherein the waste materials and metal-oxide containing products are introduced into a fluidized bed reactor and the added carbon dioxide is introduced as a fluidizing gas for the fluidized bed reactor, wherein the carbon dioxide used as the fluidizing gas is converted completely to carbon monoxide by reaction with carbon of decomposed hydrocarbons in the fluidized bed reactor and by an addition of additional carbon material, and wherein hydrogen is produced instead of hydrogen chloride at the end of the process when hydrogen ii\carri;a3\K« \S p :i\48916 02AmM ndc3P.ag .doc 31/03/05 COMS ID No: SBMI-01184873 Received by IP Australia: Time 15:41 Date 2005-03-31 31/03 '05 THU 16:31 FAX 61 3 9243 8333 GRIFFITH HACK Q0Oll -13- atoms are present in said waste materials.

19. The process of claim 18, wherein the additional carbon material is coal, graphite, or both.

The process according to claim 18 or 19, wherein the halogenated waste material is selected from the group consisting of solvents, carbon tetrachloride, chloroform, methylene chloride, tetrachloroethylene, trichloroethylene, tetrachloroethane, coolants, refrigerants, PCB, pesticides, fungicides, herbicides, halogenated plastics, PVC and mixtures thereof.

21. The process according to any one of claims 18 to 20, wherein a portion of a metal oxide that corresponds to a chlorine content of the waste materials is converted into metal chloride.

22. The process according to any one of claims 18 to 21, wherein the non-halogenated waste material is selected front the group consisting of spent oils, lubricants, fats, paints, dyes, tars, waxes, plastics, coolants, solvents, brake fluid and mixtures thereof.

23. The process according to any one of claims 18 to 22, wherein a first feed line feeds in the halogenated waste material to the reactor and a second line feeds in a product containing metal oxides to the reactor.

24. The process according to claim 23, wherein said product containing metal oxides is fed to the reactor in granulated form with a mean grain size of 3-8 mm.

The process according to claim 23, wherein said product containing metal oxides is slate.

26. A process for disposing of halogenated and non- 4ds1 e 'ondccPaqwk.Uoc ,iIo!to3 COMS ID No: SBMI-01 184873 Received by IP Australia: Time 15:41 Date 2005-03-31 31/03 '05 THU 16:31 FAX 61 3 9243 8333 GRIFFITH HACK [012 -14- halogenated waste material, comprising: introducing waste material comprising halogenated waste material to a reactor as a first reactant; introducing a halogenatable, metal oxide material which is selected form the group consisting of CaO, TiO 2 AlO0 3 SiO 2 Fe20 3 and mixtures thereof to the reactor as a second reactant; chemically reacting the first and second reactants at a temperature of 800'C to 1100'C while excluding oxygen and with said second reactants being supplied in sufficient quantity for the introduced metal oxide material to act as a metal oxide containing adduct, and separating out, from reaction product gases produced in the reaction of the first and second reactants, halogenated metal compounds, wherein hydrogen is produced instead of hydrogen chloride at the end of the process when hydrogen atoms are present in said waste materials.

27. The process of claim 26, wherein the separating out of halogenated metal compounds includes cooling halogenated metal compounds initially in gaseous form to form solid, crystalline metal compounds.

28. The process of claim 26 or 27, wherein said cooling is carried at a location downstream from the reactor.

29. The process of any one of claims 26 to 28, wherein the separating out of halogenated metal compounds occurs at a separation unit positioned downstream from the reactor.

X:'.nArieaq\Kp''gpcci\48s)16 32 andedPa;ac.dov 31/03/15 COMS ID No: SBMI-01184873 Received by IP Australia: Time 15:41 Date 2005-03-31 31/03 '05 THU 16:32 FAX 61 3 9243 8333 GRFIhHC 01 GRIFFITH HACK 91013 The process of any one of claims 26 to 29, wherein the separating out of halogenatedi metal compounds includes removal of metal chlorides while in solid form and suspended within a reaction product gas flow traveling downstream from said reactor.

31. The process of any one of claims 26 to wherein the separating out of halogenated metal compounds includes a first and a second separation stage with a first type of halogenated metal compound removed at the first stage and a second type of halogen~ated metal compound removed from the second stage.

32. The orocess of any one of claims 26 to 31, wherein the separated out haloge-nated metal compound is a metal chloride.

33. The process of any one of claims 26 to 32, wherein the separated out halogenated metal compound is subjected to further purification.

34. The process of claim 33, wherein further purification comprises distilling said halogenatedi metal compound.

The process of any one of claims 26 to 34, wherein the separating out of halogenated metal compounds includes condensing halogenated metal compounds initially in gaseous form.

36. The process of any one of claims 26 to further comprising introducing carbon dioxide to the reactor during the reaction of the fir-st and second reactants.

37. The process of any one of claims 26 to 36, wherein the waste material is a carbon containing COMS ID No: SBMI-01 184873 Received by IP Australia: Time 15:41 Date 2005-03-31 31/03 '05 THUI 16:32 FAX 61 3 9243 8333 GRIFFITH HACK 014 -16- halogenated waste material.

38. A process for disposing of halogenated and non- halogenated waste material, comprising: introducing waste material comprising halogenated waste material to a reactor as a first reactant; introducing a halogenatable, metal oxide materialwhich is selected form the group consisting of CaO, Tio 2 AO 2 0 3 Si0 2 Fe 2 0 3 and mixtures thereof to the reactor as a second reactant; reacting the first and second reactants at a temperature of 800'C to 1100°C while excluding oxygen and with said second reactants being supplied in sufficient quantity for the introduced metal oxide material to act as a metal oxide containing adduct, and separating out, from reaction product gases produced in the reaction of the first and second reactants, halogenated metal compounds, wherein the separating out of halogenated metal compounds includes a first and a second separation stage with a first type of halogenated metal compound removed at the first stage and a second type of halogenated metal compound removed from the second stage, wherein metal chlorides are removed at the first stage and SiC1 4 at the second stage, and wherein hydrogen is produced instead of hydrogen chloride at the end of the process when hydrogen atoms are present in said waste materials. H:\.<re:eag\Xt.i\bpeci\81 16 02na)ncJdfag:.- oc 31/U3/C5 COMS ID No: SBMI-01184873 Received by IP Australia: Time 15:41 Date 2005-03-31 31/03 '05 THU 16:32 FAX 61 3 9243 8333 GRFTHHC01 GRIFFITH HACK Q 0 1 -17-

39. A process for disposing of halogenated and non- halogenated waste material, comprising: introducing waste material comprising halogenated waste material to a reactor as a first reactant; introducing a halogenatable, metal oxide material which is selected form the group consisting of CaO, TiC 2 A1 2 0 3 SiO 2 Fe 2 O 3 and mixtures thereof to the reactor as a second reactant; reacting the first and second reactants at a temperature of 8O0'C to 1100'C while excluding oxygen and with said second reactants being supplied in sufficient quantity for the introduced metal oxide material to act as a metal oxide containing adduct, and separating out, from reaction product gases produced in the reaction of the first and second reactants, haiogenated metal compounds, wherein the separated out halogenated metal compound is subjected to further purification, wherein further purification comprises distilling said halogenated metal compound, and wherein hydrogen is produced instead of hydrogen chloride at the end of the process when hydrogen atoms are present in said waste materials. COMS ID No: SBMI-01 184873 Received by IP Australia: Time 15:41 Date 2005-03-31 31/03 '05 THU 16:32 FAX 61 3 9243 8333 GRIFFITH HACK 0o16 -18- Process for disposing of halogenated and non- halogenated carbon-containing waste materials according to claim 1, with reference to the example and/or drawing. Dated this 31st day of March 2005 PAC HOLDING S.A. By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia H:\aCieatg\Ke~Kt\3ccl\di916 U2AnindedPageF.doc 31/03/05 COMS ID No: SBMI-01184873 Received by IP Australia: Time 15:41 Date 2005-03-31