BG63637B1 - Method and installation for lubricants recycling - Google Patents

Abstract

The method and the installation are designed for economical recycling of lubricants with higher output and quality. The method comprises the addition of sodium or potassium base in quantities from 1 to 3 wt. % to preheated to 140-160 degrees C oils, dehydration and separation of the light hydrocarbons by minute evaporation with pressure reduction, separation and recuperation of the light oil by distillation and removal of admixtures by vacuum fraction distillation. The inventive method installation includes a tank for the waste lubricants (2), connected across a heater (3) to mixer (5) to which a tank for as base (4) is connected, the mixer, on its turn, being connected to column (6) for the separation of the water ad the light hydrocarbons, which is connected to a column for fraction distillation of light oil, connected on other side with a vacuum distillation column (10), to the bottom of which an evaporator (13) is connected. 2 claims, 1 figure

Description

Technical field

The invention relates to a method and installation for the recovery of waste lubricating oils.

Lubricants change when used, which requires a change.

The removal or regeneration of waste oils is currently a source of significant environmental pollution.

After use, these oils contain mainly solid waste, combustion waste, etc.

BACKGROUND OF THE INVENTION

Various methods of recovery are known. Spent oils are initially recovered, and those different parent oils sometimes contain more or less by-products that interfere with the course of regeneration.

The methods used so far include treatment of spent and recovered sulfuric acid oils, neutralization with lime and sodium carbonate, followed by decolourisation with activated bentonite and filtration.

A known apparatus and method for the recovery of waste oils / 1 /. The device consists of two tanks for treatment with sodium carbonate and with clay, and two centrifuges for the separation of water and spent clay from the treated oil.

This method allows the recovery of part of the waste oil but releases non-recoverable waste with a highly polluting effect.

The degree of oil regeneration in industrial devices implementing these methods does not exceed 85%, and their cost is high.

Other recovery methods are known including hydrotreating the oil after heat treatment followed by vacuum distillation. The hydrogenation of the oil is carried out in the presence of hydrodesulfurizing and hydrodewashing catalysts, which catalyze the exhaust during operation and gradually produce highly contaminated non-usable products.

Also known is a method (2) for the regeneration of waste oils, in which the dehydration and removal of chlorinated hydrocarbons is carried out in the temperature range between 100 and 200 ° C. Alkaline treatment is then carried out in a closed system at 300 ° C with a mixture of sodium and potassium carbonate. Thermal vacuum distillation at 480 ° C was followed.

SUMMARY OF THE INVENTION

The problem with the solution is to develop an economical method - for the regeneration of lightly soiled or uncontaminated waste lubricating oils, as well as a method for the regeneration of waste oils at a high rate of oil recovery.

These problems are solved by a waste oil regeneration method that involves a strong base treatment step using either a sodium or potassium base in aqueous solution. The method according to the invention involves the following sequential processing steps:

- assessment of the concentration of fuel oil, fatty acids and chlorine and homogenization of oils containing a low percentage of these components;

- preheating the regenerating oils to a temperature of 140 to 160 ° C;

- adding an aqueous solution of strong base in an amount of 1 to 3% by weight of the lubricating oil, using sodium or potassium base as the strong base;

- dehydration and separation of light hydrocarbons by instant evaporation under reduced pressure;

- separation and recovery of gas oil by distillation;

- removal of impurities by fractional distillation under vacuum, providing, on the one hand, the starting lubricating oils and, on the other, a residue comprising all impurities in concentrated form.

The instantaneous evaporation step by the dramatic reduction of pressure carried out before the impurity extraction ensures the dehydration and separation of light hydrocarbons from the treated mixture and creates the conditions for more efficient further processing.

The invention also relates to a waste oil recovery plant for carrying out the method described above.

This installation consists of a strong base mixing reactor to which a waste oil tank and a strong base tank are connected via a heating device. On the other hand, the reactor is connected to a column for the separation of water and light hydrocarbons by flash evaporation. This column is connected to a gas distillation column. After the gas oil distillation column, a vacuum distillation column is mounted to which a evaporator is connected to the bottom.

The method and installation according to the invention allow the use of waste oils to produce oils with different usable qualities, usable waste, water, light hydrocarbons and gas oil. All products obtained are recoverable, so this method avoids, in principle, the risks of environmental pollution. The method and installation according to the invention allow for a high recovery rate β of at least 90%, i.e. to obtain a regenerated oil with the qualities of a new one, eliminating the almost completely contained metals.

Examples of carrying out the invention

The invention is explained in more detail with the aid of Figure 1, which schematically represents the waste oil recovery plant according to the invention.

The collected waste oils may have different origins, for example, motor, timing, hydraulic, turbine oils, etc.

When delivering these oils to the regeneration plant, their suitability for treatment is checked.

In fact, the regeneration method according to the invention essentially relates to the removal of light constituents such as gasoline, gas oil and water without removing the heavy constituents, as well as oils having different physical properties. For example, the removal or treatment of fuel oil can only be done by a complete purification method.

High chlorine content can cause the device to wear out prematurely.

Collected oils containing a very high percentage of fuel oil, fatty acids or chlorine must be removed. In order to evaluate the concentration of these various ingredients, some of the tests used in the art are practiced.

Among them may be cited "Chlor Test", which allows to capture the presence of chlorides. Copper wire immersed in waste oil is placed on a flame. A greenish flame indicates the presence of chlorides.

Drop Test allows you to capture the presence of fuel oil. A drop of oil is placed on the chromatographic paper. A concentric spot with a yellowish halo indicates the presence of fuel oil.

Fast Test allows the presence of fatty acids in the oil to be captured. Heat 2 ml of waste oil in the presence of a sodium hydroxide tablet when, after cooling, the oil thickens, this means that it contains fatty acids.

The grouped waste oils 1, which have withstood these different tests, are collected in tank 2.

They are mixed inside the tank itself or during their extraction by classical means not shown in the figure.

The heating equipment 3 heats the pre-collected oils from tank 2 to a temperature of 140 to 160 ° C.

The base in tank 4 is fed and mixed via the gear 5 with the heated exhaust oils.

Preferably, the amount of pure base added to the waste oils is in the range of 1 to 3% by weight.

The quantity can be pre-specified depending on the quality of the used oils and the type of base used.

The base used is sodium or potassium hydroxide.

The high temperature waste oils mixed with the strong base are introduced into column 6 for extraction of water and light hydrocarbons by flash evaporation. Evaporation of water is carried out by rapid expansion of the mixture.

Water and light hydrocarbons are separated and the remaining mixture is transferred to a gas separation column 8, which is carried out by distillation.

The gas oil 9 was separated and the remaining mixture was transferred to a distillation column 10 for fractionation of the mixture of individual lubricants and separation of the residue where all impurities were concentrated.

Base oils can be divided into different fractions at different column levels - 11 and 12.

Good results are obtained by splitting in two - a base oil of 150 - Neutral-11 and a base oil of 400 to 500 - Neutral-12.

Distillation column 10 is a traditional vacuum column that allows the separation of residues that are transferred to a collection balloon 14.

The waste 15 is disposed of and is usable (for example as tar or bitumen for road construction). They can also be used as fuels.

The vacuum distillation column 10 is preferably connected to an evaporator 13 for further purification, which allows to improve the performance of the main column. Part of the energy required to raise the temperature of the exhaust oils prior to the addition of the clean base comes preferably from the recovery of energy from the lubricating oils 11, 12 at the outlet of column 10.

The spent oils are filtered successfully during their recovery and at the outlet of the tank 2 to remove the solids they contain.

Various pumps, which are not presented, ensure the circulation of the mixture and the separated products.

The method and installation according to the invention allow the use of waste oils to produce oils with different application properties: usable waste, water, light hydrocarbons and gas oil.

All the products obtained can be utilized, so this method avoids, in principle, the risks of environmental pollution.

The method allows a recovery rate of at least 90% to be obtained. This percentage is relative to the mass of the recovered oil quantities by the method according to the invention with respect to laboratory recovered oils under optimum conditions.

In one embodiment, waste disposal is contemplated by centrifugation.

The two methods of waste disposal: distillation and centrifugation can be combined, preferably using a vacuum distillation column with a evaporator at the base of the column. Thus, it is possible to obtain a high percentage of recovery with superior basic lubricating oil, to reduce the cost of investment and operation with respect to other known regeneration methods, to obtain recovered oils of the same qualities as new oils, and to remove almost all metal from them.

Moreover, all impurities are contained in residues which, as indicated, are readily appreciable.

The installation according to the invention can be operated easily with maximum reliability.

The following example in the form of tables illustrates the invention without limiting it.

Table (a) gives the results of the vacuum distillation of waste oils in a laboratory, indicating the ingredients and their refined characteristics.

Table b) gives the results of the distillation by a known method without adding a base. This method must be followed by chemical treatment to complete it by traditional acid and clay treatment, the disadvantages of which are set out above. The processing results are presented in Table c).

Table d) shows the results of oil recovery according to the invention.

In the tables, the products represent recovered components.

Rdt represents their yield (the ratio of the recovered amount to the initial amount of waste oil recovered).

T.A.N. represents their acidity (acid number).

VIS (40 ° C) represents their viscosity at 40 ° C, expressed in cantistocks.

The color is expressed in terms of the colors of standardized standards. When the numerical value is insignificant, the color and appearance are better, and this is an indication of good quality.

A comparison of Table c) and Table d) shows the high quality of the basic oil fractions obtained according to the invention. It is especially important that the metal content of the recovered oils is too low and the B yield higher. Moreover, the complex of oil fractions is easily recoverable.

The engine tests of the recovered oils according to the invention show that they are equivalent to new oils. They are of better quality than those recovered by known methods.

The indications included after the technical features indicated in the claims are solely intended to facilitate the understanding of the latter and are not intended to limit the scope of the invention.

(a) Distillation of waste oils in a laboratory

Products Yield (%) Acidity (mgKOH / g) Viscosity (40 ° C) (Cst) Color Appearance Gas oil 4.06 2.01 2.97 5 The easy part 23.15 0.75 27.05 4 cloudy The hard part 43,30 0.49 74,8 4.5 cloudy The rest 19.60 - - - - Water + Gasoline 8.39 - - - - Losses 1.50 - - - -

Distillation Yield: 66.45%

b) Distillation of waste oils in a production plant without prior alkaline treatment (Known development)

Products Yield (%) Acidity (mgKOH / g) Viscosity (40 ° C) (Cst) Color Appearance Gas oil 6.99 4.70 3.70 5 cloudy The easy part 12.40 0.10 30.57 4 cloudy The hard part 49.95 0.41 75.98 4.5 cloudy The rest 20,27 - - - - Water + Petrol + 3Lub (Dist.) Metal Content (ppm) 10,39 - - - -

Barium Calcium Tin Zinc Phosphorus Chrome Iron Silicon

Used oil 8 692 1138 694 704 5 84 The easy part <2 <1 6 <1 8 <0.5 <0.5 The hard part <2 <1 5 <1 <5 <0.5 <0.5 Gas oil <2 <1 39 2 101 <0.5 8 327 The rest 85 4901 2529 3469 2570 36 652

228

Distillation Yield: 62.35%

c) Waste oil regeneration at an acid / clay production plant (Known development)

Products Yield (%) Acidity (mgKOH / g) Viscosity Color Appearance (40 ° C) (Cst) Gas oil (without treatment) 6.99 4.70 3.70 5 cloudy The easy part 11.16 0.01 30.04 1.5 C + B The hard part 44.05 0.05 75.85 3 C + B The rest 20,27 - - - - - Water + Petrol + 3Lub (dist.) 10,39 Chemical treatment losses (ppm) Metals content (ppm) 7.14 - - - - Barium Calcium Lead Zinc Phosphorus ΧρΟΝ Silicon iron Slight part <2 <1 5 <1 <5 <0.5 <0.5 5 The hard part is <2 <1 5 <1 <5 <0.5 <0.5 5

Yield at regeneration: 55.21%

Recovery rate: 83.09% (calculated on laboratory distillation, without pre-treatment)

d) Oil regeneration in a production plant according to the invention

Products Yield (%) Acidity (mgKOH / g) Viscosity (40 ° C) (Cst) Color Appearance Gas oil 5.41 0.02 6.05 1.5 C + B The easy part 12.77 0.01 33.89 2 C + B The hard part 49.99 0.01 84.91 2.5 C + B The rest 20,44 - - - - Water + Petrol + 3Lub (Dist.) Metal Content (ppm) 11,39 - - - - Barium Calcium Lead Zinc Phosphorus Chrome Silicon iron The easy part <2 <1 <2 <1 <5 <0.5 <0.5 3 The hard part <2 <1 <2 <1 <5 <0.5 <0.5 3 Gas oil <2 <1 6 <1 95 <0.5 1 122 The rest 132 7624 2788 3500 2644 40 664 279

Yield at regeneration: 62.76%

Recovery rate: 94.45% (calculated for distillation in a laboratory, without pre-treatment)

Claims (1)

1. A method for the regeneration of waste lubricating oils, comprising a strong-base treatment step, characterized in that it consists of the following successive treatment steps: estimation of the concentration of fuel oil, fatty acids and chlorine and removal of oils containing many a high percentage of one of these ingredients; preheating the regenerating oils to 140 to 160 ° C; adding an aqueous solution of a strong base in an amount of 1 to 3% by weight of the lubricating oil, using sodium or potassium base as the strong base; dehydration and separation of light hydrocarbons by instantaneous evaporation with reduced pressure; separation and recovery of gas oil by distillation; removal of impurities by fractional distillation under vacuum to provide, on the one hand, the starting lubricants and, on the other, a residue comprising all the impurities in concentrated form. 5 2. A waste lubricating oil recovery plant, characterized in that it consists of a reservoir (2) for collecting the waste oil, connected via a heating device (3) with a strong base mixer (5) to 10 which is coupled reservoir for a strong base (4), the mixer (5) is connected to a column (6) for the separation of water and light hydrocarbons by instant evaporation, which is connected to a column (8) for the distillation of gas oil, connected on the other side with ca15 a distillation column (10) to which a evaporator (13) is connected to the bottom.