OA10185A - Method and installation for regenerating lubricating oils - Google Patents

Abstract

Process and plant for the regeneration of spent oils comprising: a tank (2) for the storage of spent oils; preheating means (3) for the preheating of spent oils; means (4) for the storage of a strong base; means (5) for mixing the strong base in a predetermined proportion with the spent oils; waste elimination means (10, 14).

Description

PCI <', <£> o 7' 7 ··> ·. ) "?" · · ·. > 7. Λ \ - 'pCT / FR 94 / 0Π308 010185

The invention relates to a method and an installation for the regeneration of used lubricating oils.

Lubricating oils generally undergo modifications and alterations during their use, which implies more or less frequent replacement. The removal or regeneration of these used oils has so far been a significant source of pollution.

After use, these oils usually contain solid residues, additives, combustion residues, etc.

Various recovery processes have been developed so far. Degraded oils are everything. first recovered and these oils of various origins are sometimes mixed with more or less foreign products likely to disturb the regeneration processes.

Up to now, the most widely used processes involve a step of treating used oils recovered by sulfuric acid and then their neutralization with lime and sodium carbonate and finally the discoloration with activated earth and filtration.

The installation and the process described in document GB-A-243,656 are particularly known. This installation comprises two tanks, allowing two treatments, one with soda and the other with the ground, and two centrifuges, ensuring the separation, one of the water and the other used land, of the oil treat.

JVIJB FEÛ LLE MOD / F / ff 2 010185

This type of process allows the recovery of a part of used oils, but generates non-reusable waste highly polluting.

The recovery rate of the industrial installations employing these processes does not exceed 85% and their implementation cost is high.

There are also known other recovery processes based on the hydrofinishing of the oil after heat treatment and its vacuum distillation. Hydrogenation of the oil is produced by hydrodesulphurization and hydrodenitrogenation catalysts.

During the implementation of these processes, the catalysts are gradually exhausted and finally give rise to highly polluting non-reusable products.

Moreover, these processes are even more expensive.

The process described in GB-A-2,022,131 is also known. In this used oil regeneration process a first phase of dehydration and removal of chlorinated hydrocarbons is carried out in a temperature range between 100 'and 200'.Then an alkaline treatment is carried out. closed system 25 to 300 ° C by a mixture of soda and potash. Thermal vacuum distillation reaching a temperature of 480.degree. C. is then carried out. The object of the present invention is therefore the development of a regeneration process of used lubricating oils with little or no pollutant and whose implementation can be done in good economic conditions. It is also an object of the present invention to provide a used oil regeneration process for a high oil recovery rate. 18! SB !! It 1Γ PCT / EN 04/00308

For this purpose, the invention relates to a process for the regeneration of used lubricating oils comprising a step of treatment with a strong base.

According to the invention, the process comprises the following successive treatment steps: a) evaluation of the concentrations of fuel, fatty acid and chlorine and elimination of oils containing a too high percentage of one of these compounds; b) preheating in which the oils to be regenerated are brought to a temperature of between 120 and 250 ° C; c) addition of a strong base in aqueous solution due to 1 to 3% of pure base in lubricating oil; D) dehydration and extraction of light hydrocarbons; e) extraction and recovery of gas oil (stripping); f) extracting the impurities by vacuum fractional distillation, separating the lubricating base oils, on the one hand, and concentrating all the impurities, on the other hand.

In various preferred embodiments, the invention has the following features taken in all their possible combinations: - Before preheating the waste oils are homogenized. In the preheating step, the oils to be regenerated are brought to a temperature of between 120 and 250 ° C. This temperature is preferably between 140 and 160 °. - The strong base is in aqueous solution. - The strong base is added at the rate of 1 to 3% pure base ennui. • 3 010185

A relaxation step (flash) carried out after the addition of the strong base and before the extraction of impurity. ensures the dehydration and extraction of light hydrocarbons from the treated mixture. The vacuum distillation column cooperates with a column bottom exhaustion evaporator. The strong base is sodium or potassium hydroxide. The strong base is sodium hydroxide. The strong base is potassium hydroxide. The invention also relates to a waste oil regeneration plant for implementing the method mentioned above.

This installation comprises: a storage tank for used oils; means for mixing and homogenizing oil oils initially contained in the storage tank; means for preheating waste oils; means for storing a strong base; - means for mixing the strong base in a specific proportion, used oils, - a unit for extracting water and light hydrocarbons by expansion (flash), - a diesel extraction unit (stripping), means for extracting impuritiescomprising a vacuum distillation unit.

Preferably the vacuum distillation unit is associated with a bottom depletion evaporator.

One embodiment of the invention will be described in more detail with reference to the single figure which is a schematic representation of the waste oil regeneration plant according to the invention. 4 010185

The waste oils collected may have various origins, for example, motor oil, gear oil or hydraulic oil, turbine oil, etc. On arrival of these oils to the regeneration unit, their suitability for treatment is verified.

In fact, the regeneration process of the invention essentially eliminates the light components, such as gasoline, gas oil and water, but does not make it possible to eliminate components as heavy as the oils themselves but With different physical properties, it could be, for example, fuel whose elimination of treatment could only be achieved by a complete refining process.

Excessive chlorine blending may be likely to cause premature wear of the plant.

Collected oils containing a high percentage of fuel oil, fatty acid or chlorine should be removed. In order to evaluate the concentrations in these different compounds, the tests that are well known in themselves are used in the field.

Among these we can mention the "Chlor Test" which makes it possible to detect the presence of chlorides. A copper wire dipped in the used oil is presented to the flame. A gypsum flame indicates the presence of chlorides.

The "Drop Test" makes it possible to detect the presence of fuel oil. A drop of oil is deposited on a chromatographic paper. A concentric spot with a yellow halo indicates the presence of fuel.

The "Fat Test" can detect the presence of fatty acids in oils. 2 ml of used oil are heated in the presence of a soda pellet: when the oil freezes, after cooling, it means that fatty acids are present. 5 010185

The collected used oils 1 having successfully undergone these various tests are combined in a tank 2.

They are then mixed either inside the same reservoir, or during their extraction by conventional means not shown in FIG.

Preheating means 3 carry the oils raised from the tank 2 at a temperature between 120 and 250 ° C and preferably between 140 and 160 ° C.

A base stored elsewhere in tank 4 is supplied and mixed by means of the used waste oils.

Preferably, a pure basic amount of from 1 to 3% by weight is added to the waste oils.

This rate can be advantageously specified according to the quality of the used oils and the nature of the baseutilized.

The base used is a strong base, preferably sodium hydroxide or potassium hydroxide. One can also consider using a mixture of these bases.

The used oils, brought to a high temperature, added strong base, feed a unit 6extraction of water and light hydrocarbons by expansion (flash). In such a unit, the evaporation of water is produced by the sudden expansion of the mixture in a flask. Water and light hydrocarbons are removed and the remaining mixture is directed to a stripping unit 8. This elimination is carried out by distillation in a column.

The gas oil 9 is then discharged and the remaining mixture is fed to a distillation column 10 allowing fractionation of the mixture into baseloading oil cuts and separation of the residue where all the impurities are concentrated.

The base oils can be separated at different levels according to the desired number of cuts. 6 010185

Good results have been obtained by separating, on the one hand, a base oil of 150 Neutral 11 and a base oil of 400 to 500 Neutral 12.

The distillation column 10 is a conventional vacuum column which allows the dissociation and extraction of the residues, which are directed to an accumulating balloon 14.

The residues 15 are then removed and are likely to be used for example as tar or bitumen for the realization of roads. They can also be used as fuels.

The vacuum distillation column 10 is preferably associated with a bottom depletion evaporator 13 to improve its efficiency. Part of the energy required to raise the temperature of the oils used prior to the addition of the pure base is derived from the energy recovery performed on the lubricating base oilcuts 11, 12 of the column outlet 10.

The used oils are advantageously filtered during their recovery and when they leave the storage tank 2, so as to eliminate the solid particles that they may contain.

Different pumps not shown ensure the circulation of the mixture and products extracted through the described installation.

The process and the installation of the invention thus make it possible, from used oils, to obtain base oils of various reusable qualities, usable residues, water, light hydrocarbons and gas oil.

All products obtained are reusable, which is why this process avoids the main risks of pollution.

This method makes it possible to obtain a minimum recovery rate of 90%. This rate is the ratio by mass of the 7 010185 quantities of oils recovered by this industrial process, compared with that of the oils recovered in the laboratory, in optimum conditions independent of any economic consideration.

In an alternative embodiment, waste disposal is performed by a centrifuge device.

The two modes of waste disposal, column distillation and centrifugation can be combined.

However, the preferred embodiment employs the vacuum distillation column associated with a column bottom exhaustion evaporator. It is thus possible to obtain an excellent level of recovery of the lubricant oil fraction, to reduce the investment and operating costs compared to other known degeneration processes, to obtain regenerated oils that are as effective as the new base oils. and remove from them almost all the metals.

Moreover, all the impurities are contained in their residues which, as already indicated, are easily valorizable. The installation of the invention can be implemented in the best conditions of reliability. The following example illustrates the implementation of the invention.

In (a), the result of the sousvide distillation of used oils in the laboratory is indicated by providing the components and their precise characteristics.

In b), the result of the distillation obtained by an earlier method is shown without the addition of base. This method must, according to the prior art, be followed by the chemical finishing treatment, by a traditional process with acid and earth, the disadvantages of which have been mentioned above. The results of this treatment are shown in c).

In d), the regeneration of the oils is represented according to the industrial process claimed. 8 010185

In these different tables, the products are the recovered components.

Yield represents their yield (ratio in mass of the quantity recovered with respect to the initial quantity of oil to be regenerated). T.A.N. represents their acidity (acid number content). VIS 40 * C represents their viscosity at 40 ° C expressed encentistocks.

The color is expressed relative to standard reference colors. The lower the numerical value indicated, the better the color and the appearance is a qualitative indication.

Ba represents barium, Ca calcium, Pb lead, Znle zinc, P phosphorus, Cr chromium, Fe iron and Si ilicium.

Comparison of Table c) with Table d) shows the superior quality of the base oil cuts obtained according to the invention. In particular the contents of metals in recovered oils are much lower and the efficiency is more important. In addition, all the cuts are easily reusable.

The engine tests of regenerated oils according to the invention have shown their equivalence to new oils. They are more efficient than those regenerated by the known processes.

The reference signs inserted after the technical characteristics mentioned in the claims, for the sole purpose of facilitating the understanding of the latter, and in no way limit the scope. 010185 A)

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Claims (8)

A lubricant regeneration process involving a heavy base treatment oil, characterized in that it comprises the following successive treatment steps: a) evaluation of the concentrations of fuel oil, fatty acid and chlorine and elimination of oils containing a percentage too much high of one of these compounds; (b) preheating in which the oils to be regenerated are brought to a temperature between 120 and 250 ° C, (c) addition of a strong base in an aqueous solution in the proportion of 1 to 3% of pure base, in lubricating oil, and (d) dehydration light hydrocarbons e) extraction and (stripping) f) extraction of the recovery of gas-oil impurities by vacuum fractional distillation providing separation into lubricating base oils on the one hand and by concentrating all impurities on the other somewhere else. 2. A method of regenerating used lubricating oils according to claim 1, characterized in that the dehydration step and extraction of light hydrocarbons is effected pardétente (flash). 3. A method of regenerating used lubricating oils according to one of claims 1 and 2, characterized in that the distillationsous column or vacuum cooperates with a column exhaust exhauster column. 4. Process for regenerating used lubricating oils according to any one of PCT / FR 04/00308. Claims 1 to 3, characterized in that the strong base is sodium hydroxide and / or potassium hydroxide. 5. Process for the regeneration of used lubricating oils according to claim 4, characterized in that the strong base is sodium hydroxide. 6. A method of regenerating used lubricating oils according to claim 4, characterized in that the strong base is potassium hydroxide. 7. Plant for the regeneration of used oils comprising: - a reservoir (2) for storing used oils, - means for preheating (3) the used oils, - means for storing (4) a strong base, - means for mixing (5) of the strong base in a given proportion to used oils, - a unit for extracting water and light hydrocarbons by expansion (6) (flash), - a diesel extraction unit (8) (stripping, and - means for extracting impurities (10,14) comprising a vacuum distillation unit (10). 8. regeneration plant ofused oils according to claim 7, characterized in that the vacuum distillation unit (10) is associated with a evaporator (13) of bottom depletion column.