MXPA99005440A - High performance method and plant for regenerating lubricating waste oil - Google Patents

Abstract

The invention concerns a method and a plant for regenerating lubricating waste oil with low content of fuel, fatty acids and chloric products. The lubricating waste oil is subjected to the following steps successively:adding strong bases in aqueous solution atthe rate of 0.5 to 3%of pure bases by mass of waste oil;dehydrating and extracting the light hydrocarbons, extracting and recuperating the gas oil (stripping);extracting the impurities. The invention is characterised in that a complementary addition of a strong base in aqueous solution at the rate of 0.1 to 1%by mass of waste oil is carried out following the dehydrating and extracting of light hydrocarbons. The treated lubricating waste oil are rid of their impurities by distillation.

Description

METHOD AND HIGH OPERATING PLANT FOR - RECOGNIZING LUBRICATING OILS The present invention relates to a process and a facility for regenerating used lubricating oils of high performance. Regeneration processes of this type are already known and, in particular, we will refer to the process described in the patent application WO-94/21761. This prior document describes a process for the regeneration of used lubricating oils wherein said oils are subjected to the following successive treatment steps: a) preheating wherein the oils to be regenerated are brought to a temperature comprised between 120 and 250 ° C. b) addition of a strong base in aqueous solution at a ratio of 1 to 3% by mass of pure bases; c) extraction of impurities. This prior document also describes different preferred embodiments of this method which generally give satisfactory results. However, it has been sought to obtain regenerated oils of even better quality. The object of the present invention is, therefore, to propose a method of this type and the corresponding installation. For this purpose, the invention relates to a process for regenerating used lubricating oils having a low content of fuel, fatty acids and chlorinated products, wherein the lubricating oils used are subjected to the following successive stages of treatment in the following order : a) selection of used oils suitable for treatment; b) adding a first quantity of a strong phase in aqueous solution; c) heating the mixture to a temperature between 120 ° C and 250 ° C; d) addition of a second amount of the strong base in aqueous solution, the first amount and the second amount of strong base in aqueous solution together represent 0.5 to 3% of pure bases in mass of used lubricating oils; e) dehydration and extraction of light hydrocarbons; f) extraction and recovery of diesel (depuration); g) extraction of impurities. According to the present invention, a complementary addition of a strong base in aqueous solution at a ratio of 0.1 to 1% of pure bases in mass of lubricating oils is carried out after step e). In different embodiments, the invention can also present the characteristics considered below in isolation or according to all its technically possible combinations: the complementary addition of strong bases is carried out during the extraction and recovery stage of diesel fuel, - the supplementary addition of strong bases is carried out subsequently to the stage of extraction and recovery of diesel oil, - after the dehydration, extraction of light hydrocarbons and depuration of diesel oil stage, the purified oil is cleaned of its impurities (residue) in a vacuum column equipped with a re-boiling system, and then subjected to an oxidation step before the addition of strong bases, and then fractionated, - the elimination of the impurities is obtained by vacuum distillation ensuring separation in lubricating base oils on the one hand and in a waste which concentrates all the impurities on the other hand. During the first addition, the amount of strong bases in aqueous solution provided can be within a range of 0.5 to 3% of pure bases in mass of used lubricating oils. This addition can be carried out totally or partially cold or hot. The heating temperature of the oils used to regenerate is within a range of 120 to 250 ° C and is a temperature at which the addition of the hot base is carried out in whole or in part. The invention will be described in detail with reference to the accompanying drawings in which: - Figure 1 is a schematic representation of a process and a prior art lubricating oil regeneration installation;; Figure 2 is a schematic representation of a procedure and a reinstallation of regeneration of lubricating oils used in a first embodiment of the invention; Figure 3 is a schematic representation of a procedure and a regeneration reinstallation of lubricating oils used according to a second embodiment of the invention; Figure 4 is a schematic representation of a process and a regeneration plant for lubricating oils used according to a third embodiment of the present invention. The collected waste oils may have diverse origins. It can be, for example, motor oil, gear oil, hydraulic oil, turbine oil, etc. The arrival of these oils in the regeneration unit verifies their suitability for treatment. In fact, the regeneration process of the invention focuses on the elimination of light components, such as gasoline, diesel and water; it also allows the elimination of products of degradation of oil and additives, but does not allow the elimination of certain components as heavy as the oils themselves and that have different physical properties. It could be, for example, fuel whose disposal or treatment could only be obtained through a complete refining procedure. An excessive chlorine content of the mixtures could cause premature wear of the installation. Collecting oils that contain a too high percentage of fuel, fatty acids or chlorine are therefore eliminated. In general, they are oils that do not comply with the regeneration tests. In order to evaluate the concentrations in these different compounds, regeneration tests well known per se in use in this field are practiced. The tests of regenerabilidad are the following: - the approves of chlorine "that allows to detect the presence of chlorides." A wire of submerged in used oil is presented before a flame, a greenish flame indicates the presence of chlorides. Drop test "allows detecting the presence of fuel. A drop of oil is placed on a chromatographic paper. A concentric spot with a yellowish halo indicates the presence of fuel. - the 'fat test' allows the presence of fatty acids in the oils to be detected, 2 ml of used oil are heated in the presence of a soda tablet: when the oil is fixed, after cooling, this means that fatty acids are found - the determination of the concentration in PCB (polychlorobiphenyl) This test is carried out and its limits are set according to the regulations in force The used oils collected 1 that approved the test set are put together in a tank 2. Said oils are mixed, either inside the tank 2, or during their extraction by conventional means not shown in the figures A base or a mixture of bases stored on the other hand in a tank 4a is provided and mixed by means 5a a oils used at room temperature between 10 and 40 ° C. Heating means 3 carry the oils taken from tank 2 and possibly mixed with the base, at a temperature between 20 and 250 ° C and preferably between 140 and 160 ° C. A base or a mixture of bases stored in a tank 4b is provided and mixed by means 5b to the used oils heated. Preferably, a quantity of pure bases comprised between 0.5 and 3% by mass is added to the waste oils. This rate, as well as its distribution between the two points of cold and hot injection, can be used profitably depending on the quality of the used oils and the nature of the base used. The base used is a strong base, preferably sodium or potassium hydroxide. We can also raise the possibility of using a mixture of these bases. The used oils, brought to a high temperature, with the addition of a base, feed a unit 6 for the extraction of water and light hydrocarbons by expansion (flash) in a unit of this type 6, evaporation of the water is produced by expansion sudden of a mixture in a balloon.

The water and the light hydrocarbons are extracted and evacuated towards the outlet 7. The remaining mixture is directed towards a diesel extraction unit 8 (depuration). This elimination is carried out by distillation in a column. The gas oil 9 is then evacuated and the remaining mixture is taken to a distillation column 10 which allows the fractionation of the mixture into lubricating base oil cuts 11, 12 and the separation of the residue 15 where all the impurities are concentrated. Base oils can be separated at different levels according to the number of cuts sought. Good results have been obtained by separating, on the one hand, a base oil of 150 Neutral 11 and on the other hand a base oil of 400 to 500 Neutral 12. The distillation column 10 is a traditional column in vacuum that allows dissociation and the extraction of waste that is directed towards a balloon of accumulation 14. The waste 15 is then evacuated and capable of being used, for example as tar or asphalt for the construction of roads. They can also be used as fuel. The vacuum distillation column 10 is preferably associated with a column bottom depletion evaporator 13 which allows its efficiency to be improved. A part of the energy necessary for raising the temperature of the oils used before the expansion preferably comes from the recovery of the energy that is effected in the lubricating base oil cuts 11, 12 of the column outlet 10. The used oils are preferably filtered during their recovery and during their exit from the storage tank 2, in such a way that the solid particles they may contain are eliminated. Several pumps, not illustrated, ensure the circulation of the mixture and of the extracted products through the installation described. An addition of complementary base solution is carried out in lower proportions than the initial additions, before the expansion, the complementary addition has proportions of the order of 0.1 to 1% by mass of pure bases in relation to the lubricating oils used. It can be carried out in different points of the installation that correspond, in each of the cases, to one embodiment. This complementary addition gives the process a flexibility that allows it to adapt to the different physicochemical requirements of regenerated base oils, that is, to provide oils whose quality is adapted to the desired results. This procedure makes it possible to ensure a better stability of the regenerated base oils and to fluidify the impurities, which allows an easier expansion of the process. In a first embodiment represented in FIG. 2, this complementary addition is carried out after the dehydration and extraction of the light hydrocarbons. A base stored in a tank 16 is provided and mixed through the means 17 with the oils used in the recirculated purified oil part. The temperature of the oil is now profitably within a range between 270 and 310 ° C. In another embodiment represented in figure 3, the addition of complementary base is carried out under the same conditions of concentration and temperature as in the first mode but after the operation of extraction of diesel fuel (depuration). A base stored in a tank 18 is provided and mixed by means 19 with the superheated purified oil directed towards the fractionating column. In the third embodiment shown in FIG. 4, after the operation of gas oil fraction (scrubbing), an evaporator 13, preferably thin layers, connected to a column under vacuum 10, allows the elimination of most of the impurities . The obtained oil is then subjected to accelerated oxidation in a cuvette 22, before the addition of a complementary amount of pure bases. For this purpose, a base stored in a tank 23b is provided and said base is mixed with the oil by the mixing means 24. The oil is then fractionated in the distillation column 20. The temperature of the oil during the addition of the base is found preferably between 200 and 300 ° C for an injection from the tank 23b just before the column 20 and is between 120 and 200 ° C for addition from a tank 23a directly in the oxidation vessel 22. The evaporator 13 is preferably an evaporator of thin layers. It is also possible to use several evaporators in succession. The residues 21 of the column 20 are, depending on the efficiency of this column and the requirements imposed on the regenerated oils, either recirculated and injected at the inlet of the column 10, either directed towards the storage of waste as the residues 15 from the distillation column 10 and from the evaporator 13. This choice depends on the concentration of residues 21 in the lubricating oil. It is carried out regularly according to the requirements imposed on regenerated oils. The color stability of the regenerated base oil 150NJ is shown in table number 1 below. Sample two has been obtained by a method according to the present invention applied according to one of figures 2 and 3. Sample 3 has been obtained through a method according to the present invention applied according to figure 4. These samples they are compared with the sample obtained with a single base injection according to the prior art. Analogously, in the case of regenerated base oil 400-500N, samples 5 and 6 obtained in accordance with the present invention are compared to sample 4 obtained in accordance with the prior art. The stability of the color and the appearance of the cuts obtained by this procedure are better and translate a superior quality of the obtained oil in comparison with the oil obtained by the previous procedures. The reference signs inserted after the technical characteristics mentioned in the claims have the sole purpose of facilitating the understanding of the latter and in no way limit the scope of said claims. ANNEX? O.l OXIDATION TEST ACCORDING TO IP 306/79 Standard Unit 1 2 3 Oil in ASTM sample 1 sample 2 sample 3 Natural State Unit Standard 4 5 6 Oil in ASTM sample 4 sample 5 sample 6 Natural State Characteristics of origin at the production date Unit Standard 1 2 3 Color D-1500 < 2 < 1.5 < 1.5 Unit Standard 4 5 6 Color D-1500 < 3 < 2 < 1.5 Characteristics before the oxidation test and after an industry storage of 6 (six) months Unit Standard 1 2 3 Color D-1500 < 3 . 5 < 2 . 5 < 1 . 5 Unit Standard 4 5 6 Color D-1500 < 3.5 < 2.5 2 Oxidation test according to standard I 306/79 Unit Standard 1 2 3 Color D - 1500 < 4.5 < 3.5 2.5 S a? 0.1 0.052 0.0094 S / TOP% 70.92 57.78 22.93 Unit Nc > rma 4 5 6 Color D - 1500 < 6 4 < 3.5 S% 0.167 0.15 0.087 S / TOP g. ? 77.67 66.08 47.54 S = total deposit TOP = total oxidation products Sample No.l = regenerated 150 N regenerated obtained in the regeneration unit according to the prior art according to figure 1. Sample No.2 = regenerated 150N cut obtained in the regeneration unit according to the present invention according to figures 2 or 3.

Sample No.3 = regenerated 150N cut obtained in the regeneration unit according to the present invention according to Figure 4. Sample No.4 = regenerated cut 400-500N obtained in the regeneration unit according to the prior art according to the figure 1. Sample No.5 = regenerated cut 400-500N obtained in the regeneration unit according to the present invention according to figures 2 or 3. Sample No.4 = regenerated cut 400-500N obtained in the regeneration unit in accordance with the present invention according to figure 4. Note: the higher the S / TOP ratio, the more unstable the oil.

Claims (1)

1. CLAIMS 1. A regeneration process of used lubricating oils with a low content of fuel, fatty acids and chlorinated products, where the used lubricating oils are subjected to the following successive stages of treatment, in the order: a) selection of suitable used oils to the treatment that meet the regeneration capacity tests; b) adding a first quantity of a strong base in aqueous solution; c) heating used oils to regenerate at a temperature between 120 and 250 ° C; d) addition of a second amount of the base in aqueous solution, the first and second quantities of strong base in aqueous solution represent, together, from 0.5 to 3% of pure bases in mass of used lubricating oils; e) dehydration and extraction of light hydrocarbons; f) extraction and recovery of diesel (depuration); g) extraction of impurities, characterized in that a complementary addition of a strong base in aqueous solution at a ratio of 0.1 to 1% of pure bases in mass of waste oils is carried out after step e). . Regeneration process according to claim 1, characterized in that the additional addition of strong bases is carried out during the extraction and recovery phase of the diesel fuel. Regeneration process according to claim 1, characterized in that the additional addition of strong bases is carried out subsequently to the extraction and recovery stage of gas oil. Regeneration process according to claim 1, characterized in that, after the dehydration, extraction of light hydrocarbons and gas oil depuration stage, the purified oil is cleaned of its impurities in a vacuum column equipped with a new system boiling, and then subjected to an oxidation step before the addition of strong bases, and then subjected to fractionation. Process for regenerating used lubricating oils according to any of claims 1 to 4, characterized in that the elimination of the impurities is obtained by vacuum distillation ensuring the separation in lubricating base oils, on the one hand, and in a residue that concentrates all impurities, on the other hand. The waste oil regeneration plant comprising: - a storage tank (2) for used oils, - heating means (3) for used oils, - storage means (4) for a strong base, - mixing means (5) of the strong base in a proportion determined in relation to the oils used, - means for removing impurities (10, 13, 14), the mixing means (5) of the strong base with the oils used and the means for removing impurities (10, 13, 14), an expansion water extraction unit (6) and a diesel extraction unit (8) (purification) and the means for extracting impurities (10, 13, 14) contain a vacuum distillation unit (10) associated with a column bottom depletion evaporator (13), characterized in that it contains means for complementary addition of a strong base after the mixing means (5) of the strong base. . An installation according to claim 6, characterized in that it contains an evaporator (3) at least placed after the diesel extraction unit. . An installation according to claim 7, characterized in that the evaporator (3) is thin layers.