CS198671B1 - Method for the continuous preparation of neutral regenerated oils from used motor oils by the molecular distillation - Google Patents

Description

The invention relates to a process for the continuous preparation of neutral recovered oils from worn engine oils by molecular distillation.

Previously known processes for the regeneration of worn motor oils using vacuum distillation provide regenerates that have some low residual acidity (0.1-0.5 mg KOH per gram of sample) and color, so that they are not suitable for direct use as base oils and require further treatment. So eg. US Pat. Nos. 3,173,859, 3,625,881, and 3,791,965 utilize clay for finishing with clay, according to U.S. Pat. 3,565,791, U.S. Pat.

Germany 1 182 377, brit. pat. 1 153 077, fr. pat. 1,516,733 utilize fine catalytic hydrogenation for purification. These combined processes are complicated and costly, and in vacuum rectification alone, the material is exposed to high temperatures for a long time in the presence of catalysing metals, in addition to further thermal decomposition, the viscous residue tending to clog the overflows in the column. These drawbacks have been eliminated by the process of PV 5172-77, which utilizes molecular distillation in a wiped film evaporator for regeneration, but the low residual acidity of the regenerate is not removed by the oil. On the other hand, methods for treating worn engine oils prior to vacuum distillation with an alkaline liquor are known. Alkaline lye at elevated temperatures disrupts solvable shells of colloidal metal particles and does not contaminate and causes flocculation (U.S. Pat. No. 3,970,470, Neth. Appl. 6,412,357, je. Pat. U.S. Pat. No. 3,620,967, Japanese Pat. disadvantage

198 671 »8871 of these processes is that flocculation and sedimentation of impurities require long times (up to hours wafers) and are not suitable for continuous operation. It is also known to use an alkaline liquor for floccularly undesirable colloidally dispersed components (U.S. Pat. No. 3,625,881), but the material to be treated must be diluted with diesel to remove the solid particles on a filtered centrifuge. A common drawback of these processes is that the precipitated particles must be removed from the environment, which complicates and prolongs the regeneration process. In addition, when the material thus treated is distilled on a vacuum rectification column, elevated temperatures and long residence times in the presence of caustic and metal catalysts result in copolymerization of additives (viscosity index improver) with oil components (aromatics), thereby worsening the flow properties on the one hand, the valuable components of ole ja are drained,

All these drawbacks are overcome by the method of preparing neutral recovered oils from worn engine oils according to the invention, which is characterized in that the worn engine oil is continuously mixed with 0.2-1.5% by weight immediately before the molecular deaerability. alkali alcohol in the form of an aqueous solution with a concentration of 30-50 wt. and the mixture is continuously heated at 150-220 ° C in a thin wiped film at atmospheric pressure, at the same time freeing moisture and low boiling hydrocarbons.

The process for preparing neutral regenerated oils according to the invention has a number of advantages over the prior art. By treating the worn engine oil according to the invention, it is possible to prepare practically neutral base oils with an acid number of 0-0.01 mg / KOH / g. The purpose of the leaching of the worn oil is to neutralize acidic substances, in particular those which pass into the regenerate in the process of molecular distillation, while avoiding floccularly colloidally dispersed undesired products. For this reason, any small amounts of sludge must be removed from the material to be treated. As a rule, acid components of the worn oil also possess fake ones, and thus, by binding in the form of alkali metal salts in the distillation residue, an improvement in the color of the regenerate can also be achieved. The material treated according to the invention is treated by thin film wiping by molecular distillation, where under short-term evaporation conditions the exposure time of the distilled substance to the effect of the elevated temperature is very short and also the working temperatures are substantially lower than in conventional vacuum distillation. polymerization of worn oil components. This also avoids the formation of highly viscous distillation residues which cause the aforementioned problems in the vacuum rectification columns, and it is possible to extract as much as possible of the undamaged engine oil from the worn engine oil, resulting in a high process yield of 70-80% from the feed. The inclusion of lye pre-treatment for molecular distillation is not a new technological operation, since even without the addition of lye, degassing of worn oil and removal of low volatile hydrocarbons and water before molecular distillation is necessary.

The worn engine oil, free from coarse meohaniocyte impurities, is mixed with 0.2-1.5 wt. alkaline lye (NaOH, KOH) in the form of an aqueous solution of β with a concentration of 30 - 50 wt. liquor.

8β 871

The mixture is continuously heated at atmospheric pressure in a thin wiped film to a temperature of 150-220 ° C, at which neutralization takes place, and at the same time the water and low volatile constituents are removed from the material. At a temperature of 100-180 ° C and a pressure of the order of 100-1 Pa, a light oil fraction of 2-12 wt.%, Suitable as a lubricating lubricant or as a fuel component, is separated from the feed in a thin wiped film. At temperature and pressure 150-300 ° C resp. 10-10 < 10 & gt ^; Pa under molecular distillation conditions, characterized by a short evaporator-condenser distance of 10-60 mm, recovered from the thin wiped film 65-80% of the feed, either as one or more fractions.

EXAMPLE

The spent engine oil with an acid number of 3.56 mg KOH / g was mixed with 1.1 wt. NaOH in the form of a 40% aqueous solution and continuously in a thin ethereal film is heated to 200 ° C at atmospheric pressure to give a fraction containing 5% of the feed containing water and volatile hydrocarbons. From this treated worn oil with continuous heating in a thin wiped film at a pressure of 50 Pa to 140 ° C, a front fraction of 5% by weight was obtained. from the feed and at a temperature of 20 ° C and a pressure of 1-3 Pa, regenerated oil is obtained in an amount of 68% of the feed. Its kinematic viscosity at 100 ° P was 74.71 mm ² s ^-1 , at 210 ° P 8.22 mm ² s ^-1 , viscosity index 83.3 acid number 0.006 mg KOH / g, fabra ASTM 2.5 · Equal the treated worn oil without the addition of lye provided a regenerate with kinematic viscosity at 100 ° P 81.36 mm ² e ¹ , at 210 ° P 8.79 nm ² s ^-1 , with a viscosity index of 86.5, an acid number of 0.246 mg KOH / g with ASTM 4.5.

Example 2

The spent engine oil with an acid number of 3.56 mg KOH / g is mixed with 0.58 wt. NaOH in the form of a 40% aqueous solution and processed analogously to Case 1. The kinematic viscosity of the regenerate at 100 ° P was 73.96 mm ² s ^-1 , at 210 ° P 8.17 mm ² s ^-1 , viscosity index 83 , 1, acid number 0.051 mg KOH / g, color ASTM 3.5.

Claims (1)

OBJECT OF THE INVENTION Process for the continuous preparation of neutral regenerated oils from worn engine oils by molecular distillation from a thin wiped film at a temperature of 150 - 300 ° C and a pressure of the order of 10 - ΙΟ ¹ Pa pr). vaporizer-condenser 10 - 60 mm characterized in that the worn engine oil is continuously mixed with 0.2 - 1.5 wt.% immediately prior to molecular distillation. alkaline lye in the form of an aqueous solution with a concentration of 30-50 wt. and the mixture is continuously heated in a thin wiped film to a temperature of 150-220 ° C under atmospheric atmosphere of 4 lacquers, at the same time freeing moisture and low-boiling hydrocarbons.