EP0230543B1 - Process for recycling spent oil - Google Patents

Process for recycling spent oil Download PDF

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Publication number
EP0230543B1
EP0230543B1 EP86116200A EP86116200A EP0230543B1 EP 0230543 B1 EP0230543 B1 EP 0230543B1 EP 86116200 A EP86116200 A EP 86116200A EP 86116200 A EP86116200 A EP 86116200A EP 0230543 B1 EP0230543 B1 EP 0230543B1
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EP
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Prior art keywords
oil
solvent
extraction
process according
extraction residue
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EP86116200A
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German (de)
French (fr)
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EP0230543A1 (en
Inventor
Rolf Dr. Dipl.-Ing. Wetzel
Hubert Dr. Dipl.-Ing. Coenen
Winfried Dipl.-Ing. Kreuch
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Krupp Koppers GmbH
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Krupp Koppers GmbH
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Priority to AT86116200T priority Critical patent/ATE41029T1/en
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M175/00—Working-up used lubricants to recover useful products ; Cleaning
    • C10M175/02—Working-up used lubricants to recover useful products ; Cleaning mineral-oil based

Definitions

  • the invention relates to a process for working up waste oil, in which the previously dewatered waste oil is subjected to extraction under supercritical conditions using a solvent which is gaseous under normal conditions and the extracted components are then separated from the separated supercritical gas phase by reducing the pressure and / or changing the temperature.
  • lubricating oils used technically are contaminated waste oils and can, as far as they are accessible to a collection, be used for further purposes. This can be done either by incineration for the purpose of energy production or by refining the used oil for the purpose of re-use as a lubricant.
  • the used oil to be processed contains impurities of all kinds, e.g. as so-called additives serving metal compounds, wear and aging residues and contaminants that result from improper storage of the used oil.
  • these contaminants of various types require special measures to protect the environment when burning waste oil and, on the other hand, must be completely separated from the product to be reused when refining the waste oil.
  • the sulfuric acid / bleaching earth process has so far been used to a particularly large extent for refining used oils.
  • the advantages of a simple technique are offset by low yields, inadequate selectivity and larger amounts of problematic waste materials, essentially acid resins and bleaching earth residues.
  • this process does not guarantee the harmless disposal of particularly problematic pollutants such as polychlorinated biphenyls, polychlorinated phenyls, haloalkanes and polycondensed aromatics.
  • Thin-film evaporation however, consists in fouling the heat exchanger surfaces and in the comparatively low selectivity of the process.
  • the invention is therefore based on the object of further developing the process for the processing of waste oil using a supercritical extraction in such a way that the above-described disposal problem is solved in a satisfactory manner, so that the processing of the waste oil without the occurrence of residues or unacceptably polluting the environment By-products can be carried out.
  • the method according to the invention basically provides two options for the disposal of the resulting solvent-free extraction residue. If conditions permit, efforts will be made to dispose of the extraction residue by storage in a landfill for cost reasons. However, if this is not possible, the extraction residue will be disposed of by thermal treatment (gasification).
  • the waste oil to be processed is fed from the collecting container 1 via line 2 to the filter system 3, in which the solid particles are separated from the waste oil by filtration and are withdrawn via line 4.
  • the waste oil freed from the solid particles passes via line 5 and the pump 6 into the distillation column 7.
  • the waste oil is subjected to a distillation in the temperature range between 120 ° C. and 250 ° C. under atmospheric pressure.
  • the gas oil-water mixture escaping overhead from the distillation column 7 is introduced via line 8 into the separating tank 9, in which the water is separated from the gas oil (so-called gas oil I) by phase separation.
  • the gas oil is discharged through line 10 and the water through line 11 deducted from the separating container 9.
  • the pre-distilled and dewatered waste oil drawn off from the distillation column 7 via the line 12 is introduced into the central part of the extraction column 13, which works at a pressure between 50 and 150 bar and a temperature between 20 ° C. and 80 ° C.
  • the pump 14 brings the waste oil to the required operating pressure of the extraction column 13, and the heat exchanger 15 ensures that the required operating temperature of the waste oil is reached.
  • the waste oil can also be fed into the extraction column 13 in its upper or lower part.
  • the required solvent is introduced via line 16 into the lower part of the extraction column 13.
  • the solvent absorbs the components of the waste oil that are soluble under the specified operating conditions, while the insoluble components collect together with the impurities in the bottom of the extraction column 13 and are withdrawn from there via line 17 under level control.
  • the valve 18 serves to regulate the extraction of the extraction residue from the extraction column 13.
  • the necessary expansion of the extraction residue to a pressure of 1 to 0.01 bar takes place in the expansion tank 19.
  • the gaseous solvent released in this process is drawn off via line 20.
  • the expansion tank 19 can be heated and provided with an agitator.
  • the upper part of the extraction column 13 acts as an amplifier section.
  • the top product obtained there is drawn off via line 21 and enters the steam-heated heat exchanger 22, in which the required reflux is generated by a slight increase in temperature, since the solubility of the oil in the supercritical solvent decreases as the temperature increases.
  • the downstream separator 23 the condensed oil is separated off and returned to the extraction column 13 by the pump 24 via line 25, where it is added as reflux to the top of the column.
  • the loaded solvent passes from the separator 23 via the line 26 into the high-pressure separator 27, in which, in the present case, the oil phase is completely separated from the solvent.
  • the separated oil phase which is the extract
  • the separated oil phase is withdrawn from the lower part of the high-pressure separator 27 under level control and passes via line 28 into the low-pressure separator 29, in which the solvent residues still present in the oil phase are separated off.
  • the amount of the extract withdrawn via line 28 is regulated by valve 30.
  • the solvent-free product oil is withdrawn via line 31 from the low-pressure separator 29 and passes via line 31 into the collecting container 32.
  • the product oil is pressed into the hydrogenation reactor 36 via the pump 34 located in line 33 and the heat exchanger 35 which the catalytic hydrogenation of the product oil takes place in the presence of commercially available hydrogenation catalysts which contain, for example, nickel as the active component.
  • the hydrogen required for this is introduced into the hydrogenation reactor 36 via line 37.
  • the halogen and sulfur compounds contained therein are converted into hydrogen or hydrogen sulfide.
  • These products are withdrawn in gaseous form from the hydrogenation reactor 36 via line 38.
  • the hydrogenated product oil in the meantime passes via line 39 into the addition container 40, into which bleaching earth can be introduced via line 41, which is mixed in the addition container 40 with stirring with the hydrogenated product oil.
  • the bleaching earth / oil mixture is then introduced via pump 42 and line 43 into vacuum distillation column 44, in which it is distilled under a vacuum of 0.002 to 0.1 bar and is thus broken down into different fractions. If it is possible to dispense with the addition of bleaching earth, the hydrogenated product oil passes directly into the vacuum distillation column 44 via line 39. Gas oil II is withdrawn via line 45 and spindle oil is removed via line 46. The distillation residue obtained in the vacuum distillation column 44 is conveyed by means of the pump 48 in line 47 into the filter system 49, in which the bleaching earth is separated off by filtration. This oily bleaching earth passes through line 51 into the gasifier 52, while the base oil obtained during the filtration is drawn off from the filter system 49 via line 50.
  • the following products are also introduced into the gasifier 52: the extraction residue from the expansion tank 19 via the line 53 and the pump 54, the gas oil from the separating tank 9 via the line 10 and the sewage sludge from the biological wastewater treatment 55 via the line 56.
  • the carburetor 52 can be an entrained-flow carburetor that works according to the known Koppers-Totzek method. Oxygen and / or air and possibly small amounts of water vapor serve as the gasification medium.
  • the gasification can be carried out under normal or increased pressure. If liquids or suspensions are to be gasified, the gasifier is equipped with so-called atomizing burners. The burners can also be preceded by heat exchangers in which the product to be gasified is brought to the temperature required for setting the required viscosity.
  • the products introduced into the carburetor 52 are gasified in a flame reaction at temperatures between 1300 ° C and 2000 ° C.
  • the additional fuel which may be required for this purpose passes through line 57 and the necessary air or oxygen via line 58 into the gasifier 52.
  • the gas which results essentially consisting of the components CO, H 2 , C0 2 , H 2 0 and N 2 is drawn off from the carburetor 52 via the line 59 and reaches the pressurized water scrubber 61 via the waste heat boiler 60.
  • the gas stream from the line 38 is also introduced into this, so that both gas streams carry out the subsequent gas treatment go through together.
  • This consists of the pressurized water wash 61 and the pressurized wash 62, the individual stages being connected to one another via the lines 63 and 64.
  • This gas treatment removes both halogen and hydrogen sulfide as well as the metal compounds originating from the oil additives from the gas. Since the gas in the waste heat boiler 60 has already been pre-cooled to the required extent, the gas drawn off via line 65 after passing through the two washing stages can be used without problems as heating gas.
  • the gasification residue (slag) obtained in the gasification is drawn off in the molten state via line 66 from the gasifier and granulated and cooled in a water bath (not shown).
  • the solvent escaping overhead from the high-pressure separator 27 is drawn off via line 67 and returns via the heat exchanger 68 to line 16, via which the solvent is reintroduced into the extraction column 13. Since the solvent circuit is almost isobaric, only a slight increase in pressure has to be brought about by the circuit compressor 69.
  • the heat exchangers 68 and 70 are used here to adjust the temperature of the solvent.
  • the solvent escaping from the low-pressure separator 29 is drawn off via the line 71 and, after having been compressed to condensation pressure in the compressor 72, reaches the condenser 73, in which it is liquefied.
  • the heat exchanger 74 in turn serves the required temperature setting.
  • the line 20 opens into the line 71 in front of the heat exchanger 74, via which line the solvent released in the expansion tank 19 is drawn off.
  • the liquefied solvent is collected in the template 75 and fed from there through the compressor 76 via line 77 into line 16, if necessary.
  • the water separated in the separating container 9 passes via line 11 into the biological wastewater treatment 55, from which the cleaned wastewater is introduced via line 78 into the receiving water.
  • the sewage sludge resulting from the wastewater treatment is, as already mentioned, fed to the gasifier 52 via line 56.
  • the drying oil emerging from the distillation column 7 was cooled to 43 ° C. via the heat exchanger 15, compressed to 100 bar with the pump 14 and then fed to the extraction column 13 at half the height. At the foot of the extraction column 13, ethane was fed in as a solvent at 43 ° C. and 100 bar.
  • the cleaned, loaded solvent phase was freed from the dissolved products following the heat exchanger 22 in the downstream high-pressure separator 27 by heating to 150 ° C. at 100 bar.
  • the separated product in an amount of 126 kg / h was drawn off at the bottom of the high-pressure separator 27 and expanded to 1 bar in the low-pressure separator 29 in order to separate off the solvent still dissolved in it.
  • the solvent released was recompressed and combined with the main solvent stream.
  • the separated product was subjected to hydrogenation in the hydrogenation reactor 36 to break down the halogenated hydrocarbons present in it and then separated into the products base oil, spindle oil and gas oil II in the vacuum distillation column 44. 2.8 kg / h of bleaching earth were added to the product given to the vacuum distillation.
  • the oily bleaching earth was filtered off from the bottom product of the vacuum distillation in the filter system 49. 74 kg / h base oil, 35 kg / h spindle oil and 14 kg / h gas oil II as well as 5.6 kg / h oiled bleaching earth were obtained.
  • the extraction residue preheated to 150 ° C. was compressed to the required pre-pressure of the carburetor 52.
  • the gas oil 1 was mixed with the oil-laden bleaching earth and the small amount of sewage sludge obtained in the biological wastewater treatment 55, and the resulting mixture was also compressed to the required admission pressure of the gasifier 52 and fed to the gasifier 52 together with the extraction residue at approx. 150 ° C.
  • This mixture was gasified in the gasifier 52 with the addition of 0.95 kg of oxygen per kg of mixture as an oxidizing agent in a flame reaction at temperatures above 1500 ° C.
  • the product of the gasification was CO and H 2 in a ratio of 2.1: 1 as well as small amounts of CO 2 and water vapor as well as traces of H 2 S and HCl.
  • the metal contents of the residue were oxidized and removed from the gasifier as ash or fly dust.
  • the hot raw gas which was still loaded with small amounts of flying dust, was subjected to the gas treatment described above, whereby heating gas, waste heat steam and saline solution were obtained.
  • it was mixed with the raw gas from the gasification before the gas treatment.

Abstract

A process is disclosed for the working up of salvage oil, in which the salvage oil is subjected to an extraction under supercritical conditions. The halogen compounds contained in the produced extract are removed by catalytic hydrogenation. The extraction residue is eliminated by deposition or thermal treatment (gasification). In the case of a thermal treatment of the extraction residue, other residues can be simultaneously converted, so that the process is performed without yield of environmentally burdensome residues or by-products. Ethane in particular and/or propane is employed as solvent for the supercritical extraction.

Description

Die Erfindung betrifft ein Verfahren zur Aufarbeitung von Altöl, bei dem das zuvor entwässerte Altöl einer Extraktion unter überkritischen Bedingungen unter Anwendung eines bei Normalbedingungen gasförmigen Lösungsmittels unterworfen wird und anschließend aus der abgetrennten überkritischen Gasphase die extrahierten Bestandteile durch Druckerniedrigung und/oder Temperaturänderung abgeschieden werden.The invention relates to a process for working up waste oil, in which the previously dewatered waste oil is subjected to extraction under supercritical conditions using a solvent which is gaseous under normal conditions and the extracted components are then separated from the separated supercritical gas phase by reducing the pressure and / or changing the temperature.

Etwa 50% aller technisch eingesetzten Schmieröle fallen als verunreinigte Altöle an und können, soweit sie einer Sammlung zugänglich sind, einer weiteren Nutzung zugeführt werden. Dies kann entweder durch Verbrennung zum Zwecke der Energiegewinnung geschehen oder durch Raffination des Altöls zum Zwecke des erneuten Einsatzes als Schmiermittel. Das aufzuarbeitende Altöl enthält hierbei Verunreinigungen der unterschiedlichsten Art, wie z.B. als sogenannte Additive dienende Metallverbindungen, Verschleiß- und Alterungsrückstände sowie Verunreinigungen, die aus der unsachgemäßen Lagerung des Altöles herrühren. Diese Verunreinigungen unterschiedlichster Art erfordern einerseits bei der Altölverbrennung besondere Maßnahmen zum Umweltschutz und müssen andererseits bei einer Raffination des Altöls vollständig von dem zur Wiederverwendung anstehenden Produkt abgetrennt werden.About 50% of all lubricating oils used technically are contaminated waste oils and can, as far as they are accessible to a collection, be used for further purposes. This can be done either by incineration for the purpose of energy production or by refining the used oil for the purpose of re-use as a lubricant. The used oil to be processed contains impurities of all kinds, e.g. as so-called additives serving metal compounds, wear and aging residues and contaminants that result from improper storage of the used oil. On the one hand, these contaminants of various types require special measures to protect the environment when burning waste oil and, on the other hand, must be completely separated from the product to be reused when refining the waste oil.

Für die Altölraffination hat das Schwefelsäure/Bleicherde-Verfahren bisher eine besonders weite Anwendung gefunden. Den Vorteilen einer einfachen Technik stehen hierbei jedoch geringe Ausbeuten, unzureichende Selektivität und größere Mengen an problematischen Abfallstoffen, im wesentlichen Säureharze und Bleicherderückstände, gegenüber. Außerdem gewährleistet dieses Verfahren nicht die schadlose Entsorgung der besonders problematischen Schadstoffe wie polychlorierte Biphenyle, polychlorierte Phenyle, Halogenalkane und polykondensierte Aromaten.The sulfuric acid / bleaching earth process has so far been used to a particularly large extent for refining used oils. However, the advantages of a simple technique are offset by low yields, inadequate selectivity and larger amounts of problematic waste materials, essentially acid resins and bleaching earth residues. In addition, this process does not guarantee the harmless disposal of particularly problematic pollutants such as polychlorinated biphenyls, polychlorinated phenyls, haloalkanes and polycondensed aromatics.

Neuere Entwicklungen von Verfahren zur Altölraffination sind:

  • - das IFP-Verfahren (Ersatz der Schwefelsäure-Raffination durch eine unterkritische Propan-Extraktion),
  • - das BERC-Verfahren (Lösungsmittelextraktion, Vakuumfraktionierung und Bleicherde- bzw. H2-Nachbehandlung),
  • - das KTI-Verfahren (Vakuum-Dünnschicht-Destillation als Reinigungsstufe),
  • - das PROP-Verfahren (Anwendung von Ammoniumphosphaten zur Reinigung und H2-Behandlung) und
  • - das Recyclon-Verfahren (Abrennung der Altölverunreinigungen durch Natrium).
Recent developments in waste oil refining processes are:
  • - the IFP process (replacement of sulfuric acid refining by subcritical propane extraction),
  • - the BERC process (solvent extraction, vacuum fractionation and bleaching earth or H 2 aftertreatment),
  • - the CTI process (vacuum thin-film distillation as a purification stage),
  • - the PROP process (use of ammonium phosphates for cleaning and H 2 treatment) and
  • - the Recyclon process (separation of the contaminated oil by sodium).

Diese Verfahren haben bisher mit Ausnahme des KTI-Verfahrens den Nachweis ihrer grundsätzlichen verfahrenstechnischen Eignung und wirtschaftlichen Technik im großtechnischen Betrieb nicht erbringen können.With the exception of the CTI process, these processes have so far not been able to demonstrate their basic suitability for process engineering and economic technology in large-scale operation.

Das KTI-Verfahren mit einem Dünnschichtverdampfer als physikalischer Reinigungsstufe wurde zwar großtechnisch eingesetzt. Die Probleme derThe CTI process with a thin-film evaporator as a physical cleaning stage was used on an industrial scale. The problems of

Dünnschichtenverdampfung bestehen jedoch im Fouling der Wärmetauscherflächen und in der vergleichsweise geringen Selektivität des Verfahrens.Thin-film evaporation, however, consists in fouling the heat exchanger surfaces and in the comparatively low selectivity of the process.

Aus der DE-OS 2 850 540 und der DE-OS 3 038 728 ist es ferner bereits bekannt, die Aufarbeitung von Altöl durch Anwendung einer Extraktion unter überkritischen Bedingungen, das heißt bei Temperaturen oberhalb TK und Drücken oberhalb PK, vorzunehmen. Die in diesen Veröffentlichungen beschriebene Arbeitsweise liefert jedoch noch keine Lösung für die schadlose Entsorgung der in den Altölen enthaltenen Halogenverbindungen. Unter Berücksichtigung der heutigen Anforderungen an den Umweltschutz ist in der Praxis eine Anwendung der überkritischen Extraktion zur Altölaufbereitung jedoch nur dann möglich, wenn dieses Problem in befriedigender Weise gelöst wird.From DE-OS 2 850 540 and DE-OS 3 038 728 it is also already known to carry out the processing of waste oil by using extraction under supercritical conditions, that is to say at temperatures above T K and pressures above PK . However, the procedure described in these publications does not yet provide a solution for the harmless disposal of the halogen compounds contained in the waste oils. Taking today's environmental protection requirements into account, the use of supercritical extraction for waste oil processing is only possible in practice if this problem is solved in a satisfactory manner.

Der Erfindung liegt deshalb die Aufgabe zugrunde, das Verfahren zur Aufarbeitung von Altöl unter Anwendung einer überkritischen Extraktion dahingehend weiterzuentwickeln, daß das vorstehend geschilderte Entsorgungsproblem in befriedigender Weise gelöst wird, so daß die Aufarbeitung des Altöls ohne Anfall von die Umwelt in unvertretbarer Weise belastenden Rückständen bzw. Nebenprodukten durchgeführt werden kann.The invention is therefore based on the object of further developing the process for the processing of waste oil using a supercritical extraction in such a way that the above-described disposal problem is solved in a satisfactory manner, so that the processing of the waste oil without the occurrence of residues or unacceptably polluting the environment By-products can be carried out.

Das der Lösung dieser Aufgabe dienende Verfahren der eingangs genannten Art ist erfindungsgekennzeichnet durch die Anwendung der Verfahrensschritte a) bis h) des Hauptanspruches.The method of the type mentioned at the outset, which is used to solve this problem, is characterized by the invention by the use of method steps a) to h) of the main claim.

Für die Entsorgung des anfallenden lösungsmittelfreien Extraktionsrückstandes sieht das erfindungsgemäße Verfahren grundsätzlich zwei Möglichkeiten vor. Wenn es die Verhältnisse erlauben, wird man aus Kostengründen bestrebt sein, den Extraktionsrückstand durch Lagerung auf einer Deponie zu entsorgen. Wenn dies jedoch nicht möglich ist, wird man den Extraktionsrückstand durch thermische Behandlüng (Vergasung) entsorgen.The method according to the invention basically provides two options for the disposal of the resulting solvent-free extraction residue. If conditions permit, efforts will be made to dispose of the extraction residue by storage in a landfill for cost reasons. However, if this is not possible, the extraction residue will be disposed of by thermal treatment (gasification).

Weitere Einzelheiten des erfindungsgemäßen Verfahrens ergeben sich aus den vorliegenden Unteransprüchen und sollen nachfolgend durch ein Ausführungsbeispiel an Hand des in der Abbildung dargestellten Fließschemas erläutert werden. Das Fließschema zeigt dabei nur die für die Verfahrenserläuterung unbedingt erforderlichen Anlagenteile, während Nebeneinrichtungen, die in keinem Zusammenhang mit dem erfindungsgemäßen Verfahren stehen, nicht dargestellt sind.Further details of the method according to the invention result from the present subclaims and are to be explained in the following by means of an embodiment using the flow diagram shown in the figure. The flow diagram shows only those parts of the plant that are absolutely necessary for the process explanation, while auxiliary devices that are not related to the process according to the invention are not shown.

Das aufzuarbeitende Altöl wird aus dem Sammelbehälter 1 über die Leitung 2 der Filteranlage 3 zugeführt, in der die Feststoffpartikel durch Filtration aus dem Altöl abgetrennt und über die Leitung 4 abgezogen werden. Das von den Feststoffpartikeln befreite Altöl gelangt über die Leitung 5 und die Pumpe 6 in die Destillationskolonne 7. Hier wird das Altöl unter atmosphärischem Druck einer Destillation im Temperaturbereich zwischen 120°C und 250°C unterworfen. Das hierbei über Kopf aus der Destillationskolonne 7 entweichende Gasöl-Wasser-Gemisch wird über die Leitung 8 in den Scheidebehälter 9 eingeleitet, in dem das Wasser durch Phasenscheidung vom Gasöl (sogenanntes Gasöl I) abgetrennt wird. Das Gasöl wird hierbei durch die Leitung 10 und das Wasser durch die Leitung 11 aus dem Scheidebehälter 9 abgezogen. Das über die Leitung 12 aus der Destillationskolonne 7 abgezogene vordestillierte und entwässerte Altöl wird in den mittleren Teil der Extraktionskolonne 13 eingeleitet, die bei einem Druck zwischen 50 und 150 bar und einer Temperatur zwischen 20°C und 80°C arbeitet. Die Pumpe 14 bringt hierbei das Altöl auf den erforderlichen Betriebsdruck der Extraktionskolonne 13, und der Wärmetauscher 15 sorgt für die Erreichung der erforderlichen Betriebstemperatur des Altöles. In Abweichung zur Darstellung im Fließschema kann die Einspeisung des Altöles in die Extraktionskolonne 13 auch in deren oberen oder unteren Teil erfolgen. Das erforderliche Lösungsmittel wird über die Leitung 16 in den Unterteil der Extraktionskolonne 13 eingeleitet. Im Gegenstrom nimmt das Lösungsmittel die unter den genannten Betriebsbedingungen löslichen Bestandteile des Altöles auf, während sich die unlöslichen Bestandteile zusammen mit den Verunreinigungen im Sumpf der Extraktionskolonne 13 sammeln und von dort niveaugesteuert über die Leitung 17 abgezogen werden. Das Ventil 18 dient dabei der Regelung des Abzuges des Extraktionsrückstandes aus der Extraktionskolonne 13. Die erforderliche Entspannung des Extraktionsrückstandes auf einen Druck von 1 bis 0,01 bar erfolgt im Entspannungsbehälter 19. Das hierbei freiwerdende gasförmige Lösungsmittel wird über die Leitung 20 abgezogen. Zur Unterstützung der Entgasung kann der Entspannungsbehälter 19 beheizt und mit einem Rührwerk versehen werden.The waste oil to be processed is fed from the collecting container 1 via line 2 to the filter system 3, in which the solid particles are separated from the waste oil by filtration and are withdrawn via line 4. The waste oil freed from the solid particles passes via line 5 and the pump 6 into the distillation column 7. Here, the waste oil is subjected to a distillation in the temperature range between 120 ° C. and 250 ° C. under atmospheric pressure. The gas oil-water mixture escaping overhead from the distillation column 7 is introduced via line 8 into the separating tank 9, in which the water is separated from the gas oil (so-called gas oil I) by phase separation. The gas oil is discharged through line 10 and the water through line 11 deducted from the separating container 9. The pre-distilled and dewatered waste oil drawn off from the distillation column 7 via the line 12 is introduced into the central part of the extraction column 13, which works at a pressure between 50 and 150 bar and a temperature between 20 ° C. and 80 ° C. The pump 14 brings the waste oil to the required operating pressure of the extraction column 13, and the heat exchanger 15 ensures that the required operating temperature of the waste oil is reached. In deviation from the representation in the flow diagram, the waste oil can also be fed into the extraction column 13 in its upper or lower part. The required solvent is introduced via line 16 into the lower part of the extraction column 13. In countercurrent, the solvent absorbs the components of the waste oil that are soluble under the specified operating conditions, while the insoluble components collect together with the impurities in the bottom of the extraction column 13 and are withdrawn from there via line 17 under level control. The valve 18 serves to regulate the extraction of the extraction residue from the extraction column 13. The necessary expansion of the extraction residue to a pressure of 1 to 0.01 bar takes place in the expansion tank 19. The gaseous solvent released in this process is drawn off via line 20. To support the degassing, the expansion tank 19 can be heated and provided with an agitator.

Der Oberteil der Extraktionskolonne 13 wirkt als Verstärkerteil. Das dort anfallende Kopfprodukt wird über die Leitung 21 abgezogen und gelangt in den dampfbeheizten Wärmetauscher 22, in dem durch geringfügige Temperaturerhöhung der erforderliche Rückfluß erzeugt wird, da bei Temperaturerhöhung die Löslichkeit des Öls im überkritischen Lösungsmittel abnimmt. Im nachgeschalteten Abscheider 23 wird das auskondensierte Öl abgeschieden und mit der Pumpe 24 über die Leitung 25 in die Extraktionskolonne 13 zurückgefördert und dort als Rückfluß auf den Kopf der Kolonne aufgegeben.The upper part of the extraction column 13 acts as an amplifier section. The top product obtained there is drawn off via line 21 and enters the steam-heated heat exchanger 22, in which the required reflux is generated by a slight increase in temperature, since the solubility of the oil in the supercritical solvent decreases as the temperature increases. In the downstream separator 23, the condensed oil is separated off and returned to the extraction column 13 by the pump 24 via line 25, where it is added as reflux to the top of the column.

Das beladene Lösungsmittel gelangt aus dem Abscheider 23 über die Leitung 26 in den Hochdruckabscheider 27, in dem im vorliegenden Falle eine Totalabscheidung der Ölphase aus dem Lösungsmittel erfolgt. Hierbei wird die abgeschiedene Ölphase, die den Extrakt darstellt, niveaugesteuert aus dem Unterteil des Hochdruckabscheiders 27 abgezogen und gelangt über die Leitung 28 in -den Niederdruckabscheider 29, in dem die Abtrennung der noch in der Ölphase vorhandenen Lösungsmittelreste erfolgt. Die Menge des über die Leitung 28 abgezogenen Extraktes wird durch das Ventil 30 geregelt. Das lösungsmittelfreie Produktöl wird über die Leitung 31 aus dem Niederdruckabscheider 29 abgezogen und gelangt über die Leitung 31 in den Sammelbehälter 32. Von hier aus wird das Produktöl über die in der Leitung 33 befindliche Pumpe 34 und den Wärmetauscher 35 in den Hydrierreaktor 36 gedrückt, in dem die katalytische Hydrierung des Produktöles in Gegenwart von handelsüblichen Hydrierkatalysatoren, die beispielsweise Nickel als aktive Komponente enthalten, erfolgt. Der hierfür erforderliche Wasserstoff wird über die Leitung 37 in den Hydrierreaktor 36 eingeführt. Durch die Hydrierung des Produktöles werden die in diesem enthaltenen Halogen- und Schwefelverbindungen in Halogen- bzw. Schwefelwasserstoff überführt. Diese Produkte werden gasförmig über die Leitung 38 aus dem Hydrierreaktor 36 abgezogen. Das hydrierte Produktöl gelangt währenddessen über die Leitung 39 in den Zugabebehälter 40, in den über die Leitung 41 Bleicherde eingeführt werden kann, die im Zugabebehälter 40 unter Rühren mit dem hydrierten Produktöl vermischt wird. Das Bleicherde- Öl-Gemisch wird sodann über die Pumpe 42 und die Leitung 43 in die Vakuumdestillationskolonne 44 eingeleitet, in der es bei einem Vakuum von 0,002 bis 0,1 bar destilliert und damit in verschiedene Fraktionen zerlegt wird. Sofern auf einen Bleicherdezusatz verzichtet werden kann, gelangt das hydrierte Produktöl über die Leitung 39 unmittelbar in die Vakuumdestillationskolonne 44. Über die Leitung 45 wird hierbei das Gasöl II und über die Leitung 46 das Spindelöl abgezogen. Der in der Vakuumdestillationskolonne 44 anfallende Destillationsrückstand wird vermittels der Pumpe 48 in der Leitung 47 in die Filteranlage 49 gefördert, in der die Bleicherde durch Filtration abgetrennt wird. Diese verölte Bleicherde gelangt über die Leitung 51 in den Vergaser 52, während das bei der Filtration anfallende Grundöl über die Leitung 50 aus der Filteranlage 49 abgezogen wird.The loaded solvent passes from the separator 23 via the line 26 into the high-pressure separator 27, in which, in the present case, the oil phase is completely separated from the solvent. In this case, the separated oil phase, which is the extract, is withdrawn from the lower part of the high-pressure separator 27 under level control and passes via line 28 into the low-pressure separator 29, in which the solvent residues still present in the oil phase are separated off. The amount of the extract withdrawn via line 28 is regulated by valve 30. The solvent-free product oil is withdrawn via line 31 from the low-pressure separator 29 and passes via line 31 into the collecting container 32. From here, the product oil is pressed into the hydrogenation reactor 36 via the pump 34 located in line 33 and the heat exchanger 35 which the catalytic hydrogenation of the product oil takes place in the presence of commercially available hydrogenation catalysts which contain, for example, nickel as the active component. The hydrogen required for this is introduced into the hydrogenation reactor 36 via line 37. By hydrogenation of the product oil, the halogen and sulfur compounds contained therein are converted into hydrogen or hydrogen sulfide. These products are withdrawn in gaseous form from the hydrogenation reactor 36 via line 38. The hydrogenated product oil in the meantime passes via line 39 into the addition container 40, into which bleaching earth can be introduced via line 41, which is mixed in the addition container 40 with stirring with the hydrogenated product oil. The bleaching earth / oil mixture is then introduced via pump 42 and line 43 into vacuum distillation column 44, in which it is distilled under a vacuum of 0.002 to 0.1 bar and is thus broken down into different fractions. If it is possible to dispense with the addition of bleaching earth, the hydrogenated product oil passes directly into the vacuum distillation column 44 via line 39. Gas oil II is withdrawn via line 45 and spindle oil is removed via line 46. The distillation residue obtained in the vacuum distillation column 44 is conveyed by means of the pump 48 in line 47 into the filter system 49, in which the bleaching earth is separated off by filtration. This oily bleaching earth passes through line 51 into the gasifier 52, while the base oil obtained during the filtration is drawn off from the filter system 49 via line 50.

In den Vergaser 52 werden außer der verölten Bleicherde noch folgende Produkte eingeleitet: Der Extraktionsrückstand aus dem Entspannungsbehälter 19 über die Leitung 53 und die Pumpe 54, das Gasöl aus dem Scheidebehälter 9 über die Leitung 10 sowie der Klärschlamm aus der biologischen Abwasserreinigung 55 über die Leitung 56. Bei dem Vergaser 52 kann es sich um einen Flugstromvergaser handeln, der nach dem bekannten Koppers-Totzek-Verfahren arbeitet. Als Vergasungsmedium dienen hierbei Sauerstoff und/oder Luft sowie ggf. geringe Mengen an Wasserdampf. Die Vergasung kann unter normalem oder erhöhtem Druck durchgeführt werden. Sofern Flüssigkeiten oder Suspensionen vergast werden sollen, wird der Vergaser mit sogenannten Verdüsungsbrennern ausgerüstet. Den Brennern können ferner Wärmetauscher vorgeschaltet werden, in denen das zu vergasende Produkt auf die für die Einstellung der erforderlichen Viskosität benötigte Temperatur gebracht wird.In addition to the oiled bleaching earth, the following products are also introduced into the gasifier 52: the extraction residue from the expansion tank 19 via the line 53 and the pump 54, the gas oil from the separating tank 9 via the line 10 and the sewage sludge from the biological wastewater treatment 55 via the line 56. The carburetor 52 can be an entrained-flow carburetor that works according to the known Koppers-Totzek method. Oxygen and / or air and possibly small amounts of water vapor serve as the gasification medium. The gasification can be carried out under normal or increased pressure. If liquids or suspensions are to be gasified, the gasifier is equipped with so-called atomizing burners. The burners can also be preceded by heat exchangers in which the product to be gasified is brought to the temperature required for setting the required viscosity.

Die in den Vergaser 52 eingeleiteten Produkte werden in einer Flammenreaktion bei Temperaturen zwischen 1300°C und 2000°C vergast. Der hierfür gegebenenfalls erforderliche Zusatzbrennstoff gelangt über die Leitung 57 und die erforderliche Luft bzw. Sauerstoff über die Leitung 58 in den Vergaser 52. Das anfallende, im wesentlichen aus den Bestandteilen CO, H2, C02, H20 und N2 bestehende Gas wird über die Leitung 59 aus dem Vergaser 52 abgezogen und gelangt über den Abhitzekessel 60 in die Druckwasserwäsche 61. In diese wird auch der Gasstrom aus der Leitung 38 eingeleitet, so daß beide Gasströme die nachfolgende Gasbehandlung gemeinsam durchlaufen. Diese besteht aus der Druckwasserwäsche 61 und der Drucklaugewäsche 62, wobei die einzelnen Stufen über die Leitungen 63 und 64 miteinander verbunden sind. Durch diese Gasbehandlung werden sowohl Halogen- und Schwefelwasserstoff als auch die aus den Öladditiven herrührenden Metallverbindungen aus dem Gas entfernt. Da das Gas im Abhitzekessel 60 bereits im erforderlichen Umfang vorgekühlt worden ist, kann das nach Passieren der beiden Waschstufen über die Leitung 65 abgezogene Gas problemlos als Heizgas verwendet werden. Der bei der Vergasung anfallende Vergasungsrückstand (Schlacke) wird im schmelzflüssigen Zustand über die Leitung 66 aus dem Vergaser abgezogen und in einem nicht dargestellten Wasserbad granuliert und gekühlt.The products introduced into the carburetor 52 are gasified in a flame reaction at temperatures between 1300 ° C and 2000 ° C. The additional fuel which may be required for this purpose passes through line 57 and the necessary air or oxygen via line 58 into the gasifier 52. The gas which results, essentially consisting of the components CO, H 2 , C0 2 , H 2 0 and N 2 is drawn off from the carburetor 52 via the line 59 and reaches the pressurized water scrubber 61 via the waste heat boiler 60. The gas stream from the line 38 is also introduced into this, so that both gas streams carry out the subsequent gas treatment go through together. This consists of the pressurized water wash 61 and the pressurized wash 62, the individual stages being connected to one another via the lines 63 and 64. This gas treatment removes both halogen and hydrogen sulfide as well as the metal compounds originating from the oil additives from the gas. Since the gas in the waste heat boiler 60 has already been pre-cooled to the required extent, the gas drawn off via line 65 after passing through the two washing stages can be used without problems as heating gas. The gasification residue (slag) obtained in the gasification is drawn off in the molten state via line 66 from the gasifier and granulated and cooled in a water bath (not shown).

Das über Kopf aus dem Hochdruckabscheider 27 entweichende Lösungsmittel wird über die Leitung 67 abgezogen und gelangt über den Wärmetauscher 68 zurück in die Leitung 16, über die das Lösungsmittel wieder in die Extraktionskolonne 13 eingeleitet wird. Da der Lösungsmittelkreislauf nahezu isobar ist, muß durch den Kreislaufkompressor 69 nur eine geringe Druckerhöhung bewirkt werden. Die Wärmetauscher 68 und 70 dienen hierbei der erforderlichen Temperatureinstellung des Lösungsmittels.The solvent escaping overhead from the high-pressure separator 27 is drawn off via line 67 and returns via the heat exchanger 68 to line 16, via which the solvent is reintroduced into the extraction column 13. Since the solvent circuit is almost isobaric, only a slight increase in pressure has to be brought about by the circuit compressor 69. The heat exchangers 68 and 70 are used here to adjust the temperature of the solvent.

Das aus dem Niederdruckabscheider 29 entweichende Lösungsmittel wird über die Leitung 71 abgezogen und gelangt, nachdem es im Kompressor 72 auf Kondensationsdruck komprimiert worden ist, in den Kondensator 73, in dem es verflüssigt wird. Der Wärmetauscher 74 dient hierbei wiederum der erforderlichen Temperatureinstellung. In die Leitung 71 mündet vor dem Wärmetauscher 74 die Leitung 20, über die das im Entspannungsbehälter 19 freigesetzte Lösungsmittel abgezogen wird. Das verflüssigte Lösungsmittel wird in der Vorlage 75 gesammelt und von dort bei Bedarf durch den Kompressor 76 über die Leitung 77 in die Leitung 16 eingespeist.The solvent escaping from the low-pressure separator 29 is drawn off via the line 71 and, after having been compressed to condensation pressure in the compressor 72, reaches the condenser 73, in which it is liquefied. The heat exchanger 74 in turn serves the required temperature setting. The line 20 opens into the line 71 in front of the heat exchanger 74, via which line the solvent released in the expansion tank 19 is drawn off. The liquefied solvent is collected in the template 75 and fed from there through the compressor 76 via line 77 into line 16, if necessary.

Das im Scheidebehälter 9 abgeschiedene Wasser gelangt über die Leitung 11 in die biologische Abwasserreinigung 55, aus der das gereinigte Abwasser über die Leitung 78 in den Vorfluter eingeleitet wird. Der bei der Abwasserreinigung anfallende Klärschlamm wird, wie bereits erwähnt wurde, über die Leitung 56 dem Vergaser 52 zugeführt.The water separated in the separating container 9 passes via line 11 into the biological wastewater treatment 55, from which the cleaned wastewater is introduced via line 78 into the receiving water. The sewage sludge resulting from the wastewater treatment is, as already mentioned, fed to the gasifier 52 via line 56.

Der vorstehend beschriebene Verfahrensgang zeigt, daß es durch eine komplexe Lösung des Entsorgungsproblems möglich ist, die Altölaufarbeitung durch überkritische Extraktion in einer Weise durchzuführen, bei der die Umwelt im Vergleich zu den bisher bekannten Verfahren deutlich weniger belastet wird. Selbstverständlich sind in Abweichung von dem im Fließschema dargestellten Ausführungsbeispiel auch gewisse Änderungen des Verfahrensablaufes möglich.The process described above shows that a complex solution to the disposal problem makes it possible to carry out the waste oil processing by supercritical extraction in a manner in which the environment is significantly less polluted than in the previously known processes. Of course, in deviation from the exemplary embodiment shown in the flow diagram, certain changes in the process sequence are also possible.

So ist bereits weiter oben festgestellt worden, daß es unter Umständen auch möglich ist, den Extraktionsrückstand durch Lagerung auf einer Deponie zu entsorgen. Da in diesem Falle der Vergaser 52 in Fortfall kommt, müssen dann auch alle anderen Rückstände, die im vorstehenden Verfahrensbeispiel mit in den Vergaser 52 eingeleitet wurden, durch Lagerung auf einer Deponie oder auf andere Weise entsorgt werden. Im Interesse eines möglichst umfassenden Umweltschutzes wird man deshalb der im vorstehenden Verfahrensbeispiel beschriebenen Arbeitsweise den Vorzug geben.It has already been stated above that it may also be possible to dispose of the extraction residue by storing it in a landfill. Since in this case the carburetor 52 comes to an end, all other residues which were introduced into the carburetor 52 in the above process example must also be disposed of by storage in a landfill or in another way. In the interest of protecting the environment as comprehensively as possible, preference will therefore be given to the procedure described in the above process example.

Ferner kann beispielsweise anstelle der beschriebenen Totalabscheidung des Extraktes in einem einzigen Hochdruck- 27 und Niederdruckabscheider 29 diese Abscheidung auch in mehreren Stufen erfolgen. Wird eine derartige fraktionierte Abscheidung der Produkte des Extraktes durchgeführt, dann sind die dabei anfallenden Fraktionen auch einzeln zu hydrieren, wenn die in den einzelnen Fraktionen vorhandenen Halogenverbindungen dies erforderlich machen.Furthermore, instead of the total separation of the extract described in a single high-pressure separator 27 and low-pressure separator 29, this separation can also take place in several stages. If such a fractional separation of the products of the extract is carried out, the resulting fractions must also be hydrogenated individually if the halogen compounds present in the individual fractions make this necessary.

Außerdem ist es möglich, statt der im Fließschema vorgesehenen getrennten Zufuhr von Gasöl, Extraktionsrückstand und Bleicherde zum Vergaser 52 diese Produkte vor dem Eintritt in den Vergaser zu vereinigen, so daß die Bleicherde im Extraktionsrückstand und Gasöl I suspendiert wird. Der Zusatz des Gasöles zum Extraktionsrückstand vor der Vergasung ist auch dann angebracht, wenn der Extraktionsrückstand eine zu hohe Viskosität aufweist, da dadurch die Viskosität herabgesetzt werden kann.It is also possible, instead of the separate supply of gas oil, extraction residue and bleaching earth to the gasifier 52 provided in the flow diagram, to combine these products before entering the gasifier, so that the bleaching earth is suspended in the extraction residue and gas oil I. It is also advisable to add the gas oil to the extraction residue before gasification if the extraction residue has too high a viscosity, since this can reduce the viscosity.

Schließlich wird es in manchen Fällen möglich sein, auf eine Reinigung des aus dem Scheidebehälter 9 ablaufenden Abwassers zu verzichten und das Wasser stattdessen mit dem Extraktionsrückstand zu vergasen. Hierbei dürfte allerdings in den meisten Fällen eine zusätzliche Zugabe von Brennstoff in den Vergaser 52 erforderlich sein. Hierbei können gegebenenfalls flüssige, kohlenwasserstoffhaltige Abfallstoffe, wie beispielsweise über die zulässigen Grenzen hinaus mit Schadstoffen belastetes Altöl, verwendet werden.Finally, in some cases it will be possible to dispense with cleaning of the waste water flowing out of the separating container 9 and instead to gasify the water with the extraction residue. In most cases, however, an additional addition of fuel to the carburetor 52 may be necessary. Liquid, hydrocarbon-containing waste materials, such as waste oil contaminated with harmful substances beyond the permissible limits, may be used here.

Die Wirksamkeit des erfindungsgemäßen Verfahrens wird durch das nachfolgende Anwendungsbeispiel belegt.The effectiveness of the method according to the invention is demonstrated by the following application example.

Hierbei wurde nasses Altöl mit 15% Wasser und 5% Gasöl 1 (KP < 170°C) in einer Menge von 175 kg/h der Destillationskolonne 7 aufgegeben. Es wurden bei 160°C und 1 bar 26 kg/h Wasser und 9 kg/h Gasöl 1 abdestilliert.Here, wet waste oil with 15% water and 5% gas oil 1 (KP <170 ° C) in an amount of 175 kg / h was added to the distillation column 7. 26 kg / h of water and 9 kg / h of gas oil 1 were distilled off at 160 ° C. and 1 bar.

Das aus der Destillationskolonne 7 austretende Trockenöl wurde über den Wärmetauscher 15 auf 43°C gekühlt, mit der Pumpe 14 auf 100 bar komprimiert sowie danach der Extraktionskolonne 13 in halber Höhe aufgegeben. Am Fuß der Extraktionskolonne 13 wurde als Lösungsmittel Äthan bei 43°C und 100 bar zugeführt.The drying oil emerging from the distillation column 7 was cooled to 43 ° C. via the heat exchanger 15, compressed to 100 bar with the pump 14 and then fed to the extraction column 13 at half the height. At the foot of the extraction column 13, ethane was fed in as a solvent at 43 ° C. and 100 bar.

Im unteren Teil der Kolonne, die mit Raschigringen gefüllt war, wurden die löslichen Bestandteile des Trockenöles durch Gegenstromextraktion vom Lösungsmittel aufgenommen. Die beladene Lösungsmittelphase wurde dem Wärmetauscher 22 (Dephlegmator) zugeführt und auf 48°C erwärmt. Hierbei ergab sich eine Teilabscheidung der schwerflüchtigen Kohlenwasserstoffe (denaturierte Additive), die der aufsteigenden beladenen Lösungsmittelphase entgegenströmten und einen Strippeffekt bewirkten, wodurch ein zusätzlicher Trenneffekt erzielt wurde. Das aufgegebene Trockenöl konnte dabei in einen Extraktionsrückstand von 14 kg/h und in eine Wertfraktion von 126 kg/h aufgetrennt werden. Der Extraktionsrückstand wurde am Fuß der Extraktionskolonne 13 abgezogen, auf 1 bar entspannt und auf 150°C aufgeheizt. Das hierbei freiwerdende Lösungsmittel wurde rekomprimiert und dem Hauptlösungsmittelstrom zugeführt.In the lower part of the column, which was filled with Raschig rings, the soluble constituents of the dry oil were taken up by the solvent by countercurrent extraction. The loaded solvent phase was fed to the heat exchanger 22 (dephlegmator) and heated to 48 ° C. This resulted in a partial separation of the low-volatility hydrocarbons (denatured additives), which flowed against the rising loaded solvent phase and caused a stripping effect, whereby an additional separation effect was achieved. The abandoned Dry oil could be separated into an extraction residue of 14 kg / h and a value fraction of 126 kg / h. The extraction residue was drawn off at the foot of the extraction column 13, let down to 1 bar and heated to 150 ° C. The solvent released was recompressed and fed to the main solvent stream.

Die gereinigte beladene Lösungsmittelphase (Extrakt) wurde im Anschluß an den Wärmetauscher 22 im nachgeschalteten Hochdruckabscheider 27 durch Erwärmung auf 150°C bei 100 bar von den gelösten Produkten befreit. Das abgeschiedene Produkt in einer Menge von 126 kg/h wurde am Boden des Hochdruckabscheiders 27 abgezogen und zur Abtrennung des in ihm noch gelösten Lösungsmittels im Niederdruckabscheider 29 auf 1 bar entspannt. Das hierbei frei werdende Lösungsmittel wurde rekomprimiert und mit dem Hauptlösungsmittelstrom vereinigt.The cleaned, loaded solvent phase (extract) was freed from the dissolved products following the heat exchanger 22 in the downstream high-pressure separator 27 by heating to 150 ° C. at 100 bar. The separated product in an amount of 126 kg / h was drawn off at the bottom of the high-pressure separator 27 and expanded to 1 bar in the low-pressure separator 29 in order to separate off the solvent still dissolved in it. The solvent released was recompressed and combined with the main solvent stream.

Das abgeschiedene Produkt wurde einer Hydrierung im Hydrierreaktor 36 zum Abbau der in ihm vorhandenen Halogenkohlenwasserstoffe unterworfen und sodann in der Vakuumdestillationskolonne 44 in die Produkte Grundöl, Spindelöl und Gasöl II aufgetrennt. Das der Vakuumdestillation aufgegebene Produkt wurde mit 2,8 kg/h Bleicherde versetzt. Die verölte Bleicherde wurde vom Bodenprodukt der Vakuumdestillation in der Filteranlage 49 abfiltriert. Es fielen 74 kg/h Grundöl, 35 kg/h Spindelöl und 14 kg/h Gasöl II sowie 5,6 kg/h verölte Bleicherde an.The separated product was subjected to hydrogenation in the hydrogenation reactor 36 to break down the halogenated hydrocarbons present in it and then separated into the products base oil, spindle oil and gas oil II in the vacuum distillation column 44. 2.8 kg / h of bleaching earth were added to the product given to the vacuum distillation. The oily bleaching earth was filtered off from the bottom product of the vacuum distillation in the filter system 49. 74 kg / h base oil, 35 kg / h spindle oil and 14 kg / h gas oil II as well as 5.6 kg / h oiled bleaching earth were obtained.

Der auf 150°C vorgewärmte Extraktionsrückstand wurde auf den erforderlichen Vordruck des Vergasers 52 komprimiert. Das Gasöl 1 wurde mit der ölbeladenen Bleicherde und der in der biologischen Abwasserreinigung 55 anfallenden geringen Klärschlammenge vermischt, und das anfallende Gemisch ebenfalls auf den erforderlichen Vordruck des Vergasers 52 komprimiert und zusammen mit dem Extraktionsrückstand bei ca. 150°C dem Vergaser 52 aufgegeben. Diese Mischung wurde im Vergaser 52 unter Zugabe von 0,95 kg Sauerstoff je kg Mischung als Oxidationsmittel in einer Flammenreaktion bei Temperaturen oberhalb von 1500°C vergast. Als Produkt der Vergasung entstanden CO und H2 im Verhältnis 2,1:1 sowie kleine Mengen an C02 und Wasserdampf sowie Spuren von H2S und HCI. Die Metallgehalte des Rückstandes wurden oxidiert und aus dem Vergaser als Asche oder Flugstaub abgezogen. Das noch mit geringen Mengen Flugstaub beladene heiße Rohgas wurde der weiter oben beschriebenen Gasbehandlung unterzogen, wobei Heizgas, Abhitzedampf und salzhaltige Lauge anfielen. Um eine getrennte Wäsche des bei der Hydrierung anfallenden HCI-haltigen Abgases zu vermeiden, wurde dieses vor der Gasbehandlung dem Rohgas der Vergasung zugemischt.The extraction residue preheated to 150 ° C. was compressed to the required pre-pressure of the carburetor 52. The gas oil 1 was mixed with the oil-laden bleaching earth and the small amount of sewage sludge obtained in the biological wastewater treatment 55, and the resulting mixture was also compressed to the required admission pressure of the gasifier 52 and fed to the gasifier 52 together with the extraction residue at approx. 150 ° C. This mixture was gasified in the gasifier 52 with the addition of 0.95 kg of oxygen per kg of mixture as an oxidizing agent in a flame reaction at temperatures above 1500 ° C. The product of the gasification was CO and H 2 in a ratio of 2.1: 1 as well as small amounts of CO 2 and water vapor as well as traces of H 2 S and HCl. The metal contents of the residue were oxidized and removed from the gasifier as ash or fly dust. The hot raw gas, which was still loaded with small amounts of flying dust, was subjected to the gas treatment described above, whereby heating gas, waste heat steam and saline solution were obtained. In order to avoid separate washing of the HCI-containing exhaust gas obtained during the hydrogenation, it was mixed with the raw gas from the gasification before the gas treatment.

Zur Verdeutlichung der Ergebnisse des dargelegten Verfahrens im Hinblick auf den Abbau der im Altöl enthaltenen Schadstoffe wie PCB, PCT, der Chloralkane und der Metallgehalte dient nachfolgende Tabelle:

Figure imgb0001
The following table serves to clarify the results of the described process with regard to the degradation of the pollutants contained in the waste oil such as PCB, PCT, the chloroalkanes and the metal contents:
Figure imgb0001

Claims (12)

1. Process for reprocessing spent oil, in which the previously dehydrated spent oil is subjected to an extraction under supercritical conditions, using a solvent which is gaseous under standard conditions, and the extracted constituents are then precipitated from the supercritical gas phase, which has been separared off, by lowering the pressure and/or altering the temperature, characterized by the application of the following process steps:
a) the solid impurities present in the spent oil are removed by filtration;
b) the filtered spent oil is subjected to an atmospheric distillation in the temperature range between 120°C and 250°C;
c) the incipiently distilled spent oil is subjected to a supercritical extraction under pressures of 50 to 150 bar and at temperatures of 20°C to 80°C, whereupon the constituents of the extract are precipitated in one step or fractionally from the supercritical gas phase, which has been separated off, under pressures between 50°C and 150 bar and at temperatures between 40°C and 200°C;
d) the precipitated extract is freed from solvent residues still present therein by single-stage or multi-stage let-down to a pressure of 1 to 0.01 bar at temperatures between 40°C and 200°C;
e) the solvent-free extract is subjected to a catalytic hydrogenation under a pressure of 50 to 150 bar and at a temperature between 250°C and 400°C, the gas stream issuing from the hydrogenation being purified by water-scrubbing under pressure and/or alkali-scrubbing under pressure;
f) the extraction residue resulting from the extraction stage is freed of the solvent dissolved therein by a single-stage or multi-stage let-down to a pressure of 1 to 0.01 bar at temperatures between 40°C and 200°C;
g) the solvent-free extraction residue is disposed of by dumping or thermal treatment, and
h) the solvent recovered from the extraction residue is combined with the solvent recovered from the extract and, after appropriate compression, added to the main solvent stream which is recycled to the extraction stage.
2. Process according to Claim 1, characterized in that the hydrogenated extract, if appropriate with addition of bleaching earth in a quantity of up to 5% by weight, is fractionated by vacuum distillation.
3. Process according to Claims 1 and 2, characterized in that the solvent-free extraction residue is gasified in a flame reaction in the presence of oxygen and/or air at temperatures between 1300°C and 2000°C, the resulting gas, consisting essentially of the components CO, H2, C02, H20 and N2, being freed in a downstream gas purification from undesired constituents, in particular the metal compounds originating from the oil additives.
4. Process according to Claims 1 to 3, characterized in that the gas oil I obtained in the atmospheric distillation of the spent oil is gasified together with the extraction residue.
5. Process according to Claims 1 to 4, characterized in that the gas oil I is admixed to the extraction residue before gasification, in order to reduce the viscosity.
6. Process according to Claims 1 to 5, characterized in that the oil-contaminated bleaching earth arising in the vacuum distillation of the hydrogenated extract is suspended in the extraction residue and gas oil I and gasified together with the latter.
7. Process according to Claims 1 to 6, characterized in that the water arising in the atmospheric distillation of the spent oil is gasified together with the extraction residue.
8. Process according to Claims 1 to 7, characterized in that the gasification of the water arising in the atmospheric distillation of the spent oil is carried out with addition of fuel.
9. Process according to Claims 1 to 8, characterized in that liquid hydrocarbon-containing waste materials are added to the water, arising in the atmospheric distillation of the spent oil, before the gasification.
10. Process according to Claims 1 to 6, characterized in that the water arising in the atmospheric distillation of the spent oil is processed and the treatment sludge thus obtained is gasified together with the extraction residue.
11. Process according to Claims 1 to 10, characterized in that ethane or propane as well as mixtures of these gases are used as the solvent for the extraction.
12. Process according to Claims 1 to 11, characterized in that the solvent used contains an addition of butane.
EP86116200A 1986-01-29 1986-11-21 Process for recycling spent oil Expired EP0230543B1 (en)

Priority Applications (1)

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AT86116200T ATE41029T1 (en) 1986-01-29 1986-11-21 PROCESS FOR REFURBISHING ALTOEL.

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DE3602586 1986-01-29
DE19863602586 DE3602586A1 (en) 1986-01-29 1986-01-29 METHOD FOR REFURBISHING ALTOEL

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EP0230543B1 true EP0230543B1 (en) 1989-03-01

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JP (1) JPS62184097A (en)
AT (1) ATE41029T1 (en)
DE (2) DE3602586A1 (en)
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JPS62184097A (en) 1987-08-12
EP0230543A1 (en) 1987-08-05
DE3602586A1 (en) 1987-07-30
ATE41029T1 (en) 1989-03-15
ES2006695B3 (en) 1989-10-16
US4797198A (en) 1989-01-10
DE3662205D1 (en) 1989-04-06

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