Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G21/00—Refining of hydrocarbon oils, in the absence of hydrogen, by extraction with selective solvents
  • C10G21/006—Refining of hydrocarbon oils, in the absence of hydrogen, by extraction with selective solvents of waste oils, e.g. PCB's containing oils

Definitions

• the present invention relates to a method of decontaminating mineral oils generally and dielectric silicone fluids from polychlorobiphenyl by means of a solvent.
• PCB polychlorobiphenyl
• the dissolving step of polychlorobiphenyl and possible oxidized compounds contained in the fluid to be decontaminated occurs at a temperature ranging from 50° to 80°C.
• the stripping step accurs under vacuum and in an atmosphere of inert gas, preferably nitrogen.
• the mixing and dissolving, decantation and/or centrifugation and/or stripping steps can be sequentially repeated until the fluid will be fully decontaminated.
• the solvent is in the liquid condition at the operative temperature in order to facilitate its mixing with the fluid to be decontaminated and further it has a good heat-stability, a good water miscibility, a very small toxicity and a very low cost.
• the solvent has a lower boiling temperature both than that of the fluid to be decontaminated and that of PCB in order that it can be readily recovered for reuse, this temperature being however higher than the operative temperature.
• the solvent has a higher density than that of the fluid to be decontaminated in order to facilitate the decantation and/or centrifugation steps.
• the solvent has a low solubility towards the components of the fluid under treatment and a good affinity to the biphenylchlorinated and oxidized compounds.
• a pyrrolidone or an alkylderivative thereof is employed as a solvent such as 1-methyl -2-pyrrolidone or 2-pyrrolidone.
• the oil 0 under treatment is pumped by a circulating pump PC1 through a three-way valve V1, into a static mixer M, in which the pyrrolidone is fed through a line 3 and the so obtained mixture is caused to flow into a set of heaters R1, which are thermostatically controlled at a temperature of 50° to 80° C so as to dissolve the polychlorobiphenyl and the possible oxidized compounds contained in the fluid under treatment in the pyrrolidone.
• the mixture flows out of the set of heaters R1 and through a serv-ovalve V2, enters the centrifuge C, where the pyrrolidone is separated and fed, through a line 4, to the pyrrolidone storage tanks SP1, SP2, through a three-way valve V5.
• the oil separated by the centrifuge C having still a 2% of pyrrolidone content, is caused to flow through a line 2 in a collecting tank SO and then through a three-way valve V3 and a line 5 to be recycled through a line 8 to valve V1 in order that the above mentioned mixing and dissolving step is repeated to further lower the polychlorobiphenyl content therein or else it a is caused to flow through a line 6 and circulating pump PC2 in a second set of heaters R2 which are thermostatically controlled at a temperature of 80°C and then in a centrifugal separator SE which is under a vacuum generated by the vacuum pump PV and in which the stripping of the dissolved pyrrolidone rests is performed under an inert gas stream, preferably a nitrogen stream.
• the PCB containing pyrrolidone is entrained by the nitrogen stream up to the upper outlet of the separator SE, and conveyed to a water cooled condenser RF from where it is discharged into the drain tank S1 under the vacuum generated by the vacuum pump PV.
• the pyrrolidone flowing out of the centrifuge and stored in the tanks SP1 and SP2 in the meantime is recycled to the mixer M through the three-way valve V6, the line 9 and the circulating pump PC4 for its reuse in the dissolving step of the PCB contained in the oil.
• This recycling step is carried out until the PCB in the pyrrolidone has reached such a percent as to permit a convenient separation by distillation which is carried out in a conventional distillation plant not shown.
• the oil is drained from the centrifugal separator SE through a line 7 and pumped by means of a circulating pump PC3 through a three-way valve V4 to the drain SC or else recycled through a line 8 to the valve Vl to be again subjected to the so far described treatment.

Landscapes

• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Silicates, Zeolites, And Molecular Sieves (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=11212369

Family Applications (1)

Country Status (2)

Cited By (6)

Citations (5)

• 1982
  • 1982-11-11 IT IT24174/82A patent/IT1154554B/it active
• 1983
  • 1983-10-18 EP EP83830204A patent/EP0109366A1/en not_active Withdrawn

Patent Citations (5)

Non-Patent Citations (1)

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