Classifications

• • 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
  • C10M175/0075—Working-up used lubricants to recover useful products ; Cleaning synthetic oil based

Definitions

• the present invention relates to a method for decontaminating modern lubricating oils by the extraction of heavy metals, sulfur compounds and phosphate compounds.
• Lubricating oils have undergone a very strong development in the last fifteen years. This development is mainly due to the increase in performance of thermal engines put into service in recent years.
• Used lubricating oils come mainly from the draining process of automobile engines. These used oils are extremely toxic and a law imposes their collection and disposal in approved centers throughout Europe and the North American countries.
• Used oil also known as engine drain oil, consists of the above ingredients, to which is added the soiling due to the operation of the engines at operating temperatures (more than
• this oil contains volatile constituents (water, petrol, diesel), oil-soluble compounds formed by oxidation (resins, metallic soaps, additives of viscosity index, organometallic compounds), compounds insoluble in the oils
• additives containing a metal dispersing additives, ashless additives, antioxidant and anti-corrosive additives, metals from pipes or fittings (iron, copper, lead), bearings (silver, cadmium), or fuels
• the mineral and synthetic oils contained in the drain oils keep good specific qualities after their use, because they are very thermally stable.
• the invention solves this technical and economic problem by a process for decontaminating lubricating oils, containing mineral oils and semi-synthetic and synthetic oils, used, called drain oils, characterized by the following steps: a) the oils to be treated are placed in a container, 1 to 2% by weight of glycol is added to them, the mixture is heated to 60 ° C., the mixture is stirred and then allowed to cool and decant, so that an aqueous phase containing the glycol and the phenolic products extracted from the oily phase as well as the suspended matter and the residues of silicone oil possibly present as anti-foaming additive, b) the aqueous phase is drawn off, a chelating agent.
• a coagulant is added to the oily phase obtained after centrifugation, in a stoichiometric amount or slightly greater than the stoichiometric amount relative to the compounds to be eliminated in the step, in an acidic aqueous medium to extract the iron, and the aqueous phase is separated obtained
• step d) barium hydroxide in suspension or in solution is added to the oily phase, in a stoichiometric amount or slightly greater than the stoichiometric amount relative to the compounds to be eliminated in the step, in water to precipitate the sulfate and phosphate ions in the form of barium sulfate and phosphate which are separated by decantation or by centrifugation, e) a fractional distillation is carried out to recover the basic constituents of the oils, and optionally a discoloration of the products thus obtained, steps b and c and c and d can be reversed provided that step d is carried out after l 'step b.
• step b is repeated after step c.
• the discoloration of step e is carried out with a clay.
• the coagulating agent of step c is chosen from the group comprising hydroxides of trivalent metals, amines and polyamines. and the acid used to bring the pH to an acid value is an organic acid or a strong inorganic acid.
• drain oils come only from motor vehicles, that is to say when they have not been mixed - for transport problems - with other used oils of industrial origin, it is possible to simultaneously carrying out steps b and c, that is to say simultaneously carrying out the addition of the chelating agent and the coagulant.
• the problem with decontaminating used oils is as follows: metals, heavy metals, part or all of the sulfur compounds, phosphate compounds, chlorine, chlorine compounds and phenolic compounds must be removed.
• the decontamination process consists of: pumping the waste oils into a cylindrical tank with a conical base, equipped with a heating coil and a means of agitation such as a counter-rotating propeller or compressed air.
• the used oil is mixed with 1 to 2% glycol to remove the phenolic compounds. The whole is brought to a temperature of at least 60 ° C. stirred, then allowed to stand to obtain separation of the phases by decantation.
• the aqueous phase is positioned at the bottom of the tank, that is to say in the conical part, provided with a withdrawal tap; this aqueous phase contains the glycols mixed with the phenolic products and all the particles in suspension (iron, carbon, sand, etc.) which will have deposited, as well as the residual silicone oil (anti-foaming additive). This aqueous phase mixed with these components is drawn off in order to leave only the oily phase in the tank.
• the whole is brought to a temperature between 60 ° C and 80 ° C and stirred for at least one hour to complex the heavy metals (including zinc) with the chelating agents.
• the whole is centrifuged in order to separate the oil from the complexed heavy metals which are in the aqueous solution.
• This operation extracts between 80 and 90% of the heavy metals while the sodium neutralizes the chlorine.
• the oily phase is directed into another tank of the conical bottom type.
• a coagulant is then added in small quantities in an acid medium which allows the extraction of iron.
• the coagulant is chosen, for example, from the group comprising hydroxides of trivalent metals, amines and polyamines and the acid used to bring the pH to an acid value is an organic acid or a strong inorganic acid.
• barium hydroxide suspended in water is added, this hydroxide precipitates the phosphate and sulfate ions. It should be noted that the use of this barium hydroxide allows the use of sulfur chelating agents, because its action makes it possible to control the level of residual sulfur in the oils, according to the wishes of the end customer, who may require levels residual sulfur in the oil variable, but not exceeding a threshold generally between 3000 and 3500 ppm.
• the whole is then decanted or centrifuged, which makes it possible to obtain a decontaminated oil which can be distilled by fractionation.
• Decontamination due to the elimination of zinc and its derivatives allows distillation all the easier to conduct when the fouling phenomena due to the recombination of zinc with the products at the bottom of the column are eliminated. If a higher degree of purity of the oil is required, a phase can optionally be repeated with a mixture of chelating agents, if necessary.
• the phases of the treatment may be modified, for example the treatment with barium hydroxide may precede the phase of elimination of heavy metals.
• Another advantage of this decontamination treatment is that it makes it possible to replace, in the final treatment, bleaching earth activated by a simple clay (bentonite and derivatives). The cost advantage is considerable, a bleaching earth worth 6 to 8 times the price of a clay.
• this decontamination carried out in the initial phase before distillation makes it possible to preserve the distillation unit and to conduct it at very low temperature, which will not induce cracking phenomenon polymers and therefore to separate them from the oil much more easily and to obtain a fractionation which is much easier to conduct.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• Lubricants (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

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• 1999
  • 1999-06-23 FR FR9908021A patent/FR2795421B1/fr not_active Expired - Fee Related
• 2000
  • 2000-06-21 EP EP00951623A patent/EP1190023A1/de not_active Withdrawn
  • 2000-06-21 WO PCT/FR2000/001705 patent/WO2001000756A1/fr not_active Application Discontinuation
  • 2000-06-21 AU AU64502/00A patent/AU6450200A/en not_active Abandoned

Non-Patent Citations (1)

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