RU2775171C1 - Method for recovery of used mineral oils that do not contain additives - Google Patents

Abstract

FIELD: waste recovery.

SUBSTANCE: invention relates to methods for the recovery of mineral oils. A method is described for the recovery of used mineral oils that do not contain additives by selective purification with N–methylpyrrolidone at a temperature no higher than 90°C, settling until the phase boundary appears, separating the extract solution from the purified oil solution, followed by regeneration of N-methylpyrrolidone from the extract solution by distillation, moreover, regeneration with N–methylpyrrolidone from the purified solution the oils is carried out by washing, including dilution of the purified oil solution with water in an amount of 100-110, wt. %, relative to the purified oil solution, stirring for 5 minutes, settling for 20 minutes, separation of purified oil from an aqueous solution of N–methylpyrrolidone, drying of purified mineral oil by evaporation of water at a temperature not exceeding 90°C in vacuum, dehydration of N–methylpyrrolidone by evaporation of water for reuse in the process of selective cleaning.

EFFECT: improvement in the quality of purified oil.

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Description

The invention relates to the oil refining industry and can be used for the regeneration of used mineral oils that do not contain additives.

A known method of regeneration of used mineral oils, including selective purification of N-methylpyrrolidone (N - MP) at a temperature of 65÷90°and the ratio of used oil: solvent 100:70-100:150 wt. % (see Art. Pykhalova, N.V., Makarova, D.A., Tleugaliev, D.R., Sultanov, T.Kh. Method for restoring the properties of used oils. All-Russian Interdisciplinary Scientific Conference "Science and Practice - 2020" (Astrakhan, October 19-30, 2020) materials. - Astrakhan: ASTU Publishing House, 2020. - Access mode: 1 CD disk - state registration number 0322100459). The improvement of the quality indicators of purified oil compared to used oil occurs due to the selective extraction of undesirable components (resins, polycyclic hydrocarbons, acidic products) by a polar solvent - N - MP, which, as a rule, are either polar or capable of polarizing substances. However, the presented article does not describe a method for regenerating a solvent from a purified oil solution, which significantly affects its properties. In particular, prolonged overheating of a solution of purified oil in N-methylpyrrolidone during regeneration at a temperature exceeding 90° C. causes a deterioration in the color of the oil.

The closest in technical essence and the achieved effect to the proposed invention is a method for the regeneration of used mineral oils by selective purification using N-methylpyrrolidone (see Art. Pykhalova N.V., Tleugaliev D.A. The method of regeneration of used mineral oil. conference of the faculty of the Astrakhan State Technical University (62PPS), Astrakhan: ASTU Publishing House, 2018. - Access mode: 1 CD - disk. - state registration number 0321803357). The article describes a method for regenerating used motor oil using N-MP selective purification. The regeneration of the solvent from a solution of purified oil and extract solution was carried out by distillation at a temperature of 130-132°C in a stream of nitrogen in a vacuum. By this method, it was possible to obtain a purified oil with a color of 4 units. on the CNT scale. It is difficult to obtain oils with the best color values, determined on the CNT colorimeter, by this method, since with prolonged overheating at temperatures above 90 ° C, the oil becomes gummed and, as a result, darkens. The proposed method allows to solve this problem.

EFFECT: improved quality of refined oil.

It is achieved by the fact that in a known method, including selective purification of used mineral oil containing no additives with N-methylpyrrolidone at a temperature not exceeding 90 ° C, settling until a phase boundary appears, separation of the extract solution from the purified oil solution, followed by regeneration of N- methylpyrrolidone from the extract solution by distillation, the regeneration of N-methylpyrrolidone from the purified oil solution is carried out by washing, which includes diluting the purified oil solution with water in an amount of 100-110 wt. % with respect to the purified oil solution, stirring for 5 minutes, settling for 20 minutes, separating the purified oil from an aqueous solution of N - methylpyrrolidone, drying the purified oil by evaporating water at a temperature not exceeding 90 ° C in vacuum, dehydrating N - methylpyrrolidone by evaporating water for reuse in the selective purification process.

The method is carried out as follows: used mineral oil containing no additives is mixed with N-methylpyrrolidone in the ratio of used oil: solvent 100:80-100:115 wt. %, heated to a temperature not exceeding 90 ° C, kept at this temperature for 20 minutes, stirred for 5 minutes, settled for 20 minutes - 24 hours, depending on the type of oil and its contamination, and after the appearance of the phase boundary, it is separated into a solution of purified oils and extract solution, then the purified oil solution is diluted with water, taken in an amount of 100-110 wt. % of the purified oil solution for washing N - methylpyrrolidone, stirred for 5 minutes, settling for 20 minutes, the purified oil is separated from the aqueous solution of N-methylpyrrolidone, the purified oil is dried at a temperature not exceeding 90 ° C in a vacuum and pumped out for storage and subsequent use for its intended purpose, and water is evaporated from an aqueous solution of N-methylpyrrolidone, anhydrous N-methylpyrrolidone obtained from solutions of purified oil and an extract solution, after cooling, is used for reuse, and the extract freed from N-methylpyrrolidone is pumped out for storage.

The method is illustrated by the following examples.

Example 1

Under laboratory conditions, the original waste mineral turbine oil TP-22 was placed in an amount of 234.86 g into an extractor, which is a funnel with a volume of 500 ml with a jacket for supplying heating water at a given temperature from a thermostat, equipped with a stirrer, and 185.96 g of N -methylpyrrolidone, that is, in a ratio of 100:80 mass. %. The mixture of solvent and waste mineral turbine oil TP-22 was heated to 90°C and kept at this temperature for 20 minutes, then stirred for 5 minutes. After settling for 24 hours at room temperature and the appearance of the phase boundary, the extract solution and the purified oil solution were separated. Received 230.78 g of a solution of purified oil in N-methylpyrrolidone. N-methylpyrrolidone was separated from the purified oil solution by washing in a separating funnel. For this, 253.14 g of water at room temperature, that is, in the amount of 110 wt. % relative to a solution of purified oil, stirred for 5 minutes, defended for 20 minutes. The solution of N-methylpyrrolidone in water was poured into a separate container. The amount of N-methylpyrrolidone was 253.63 g. The water content of the purified oil was 0.03% wt. Water was separated by evaporating it from the purified oil at 90° C. under vacuum at a residual pressure of 0.92 kPa. The output of purified mineral turbine oil was 223.39 g, i.e. 95.12 wt. % of the original used mineral turbine oil. From the extract solution at a temperature not exceeding 132°C in vacuum at a residual pressure of 0.92 kPa, 177.65 g of N-methylpyrrolidone was distilled off. The resulting N-methylpyrrolidone was recyclable. Waste in this process was an extract consisting of undesirable components of used mineral turbine oil, the amount of which was 2.97 wt. % of the original used mineral turbine oil.

Example 2

The original waste mineral turbine oil TP-22 was placed in an amount of 182.58 g into an extractor, which is a funnel with a volume of 500 ml with a jacket for supplying heating water at a given temperature from a thermostat, equipped with a stirrer, and 144.72 g of N-methylpyrrolidone was added to it. , that is, in a ratio of 100:80 mass. %. The mixture of solvent and waste mineral turbine oil TP-22 was heated to 80°C and kept at this temperature for 20 minutes, then stirred for 5 minutes. After settling for 20 min. and the appearance of the phase boundary, the extract solution and the purified oil solution were separated by draining the extract solution from the bottom of the extractor. Received 211.54 g of a solution of purified oil in N - methylpyrrolidone. N-methylpyrrolidone was separated from the purified oil solution by washing in a separating funnel. For this, 212.01 g of room temperature water, that is, in an amount of 100 wt. % relative to a solution of purified oil, stirred for 5 minutes, defended for 20 minutes. The solution of N-methylpyrrolidone in water was poured into a separate container. The amount of N-methylpyrrolidone was 249.57 g. The yield of purified oil was 168.23 g, i.e. 79.53 wt. % of the original used mineral turbine oil. Its water content was 0.03 wt. %. Water was separated by evaporation from the purified oil at 85° C. under vacuum at a residual pressure of 0.92 kPa. From the extract solution at a temperature not exceeding 132°C in vacuum at a residual pressure of 0.92 kPa drove 100.05 g of N-methylpyrrolidone. The resulting N-methylpyrrolidone was recyclable. Waste in this process was an extract consisting of undesirable components of used mineral turbine oil, the amount of which was 6.37 wt. % of the original used mineral turbine oil.

Example 3

The original waste mineral turbine oil TP-22 was placed in an amount of 185.62 g into an extractor, which is a funnel with a volume of 500 ml with a jacket for supplying heating water at a given temperature from a thermostat, equipped with a stirrer, and 214 g of N-methylpyrrolidone was added to it, then is in the ratio of 100:115 wt. %. A mixture of solvent and waste mineral turbine oil TP-22 was heated to 90°C and kept at this temperature for 20 minutes, then stirred for 5 minutes. After settling for 20 hours and the appearance of a phase boundary, the extract solution and the purified oil solution were separated by draining the extract solution from the bottom of the extractor. Received 182.93 g of a solution of purified oil in N-methylpyrrolidone. N-methylpyrrolidone was separated from the purified oil solution by washing in a separating funnel. To do this, 183.42 g of water at room temperature was added to a solution of purified oil in N-methylpyrrolidone, placed in a separating funnel, stirred for 5 minutes, and the solution was settled for 20 minutes. The solution of N-methylpyrrolidone in water was poured into a separate container. Its amount was 223.46 g. The yield of purified oil was 176.59 g, i.e. 96.53 wt. % of the original used mineral turbine oil. Its water content was 0.03 wt%. Water was separated by evaporating it from the purified oil at 90° C. under vacuum at a residual pressure of 0.92 kPa. From the extract solution at a temperature not exceeding 132°C in vacuum at a residual pressure of 0.92 kPa, 204.93 g of N-methylpyrrolidone were distilled off. The resulting N-methylpyrrolidone was recyclable. Waste in this process was an extract consisting of undesirable components of used mineral turbine oil, the amount of which was 3.47 wt. % of the original used mineral turbine oil.

Qualitative indicators of refined oil samples are presented in Table 1.

Table 1 shows that the proposed method can significantly improve the main indicators of the quality of the regenerated oil. In all cases, there is an improvement in color, acid number, viscosity index, flash points and pour points of the refined oil. The density of the refined oil samples complies with existing requirements. Purified oil obtained by the proposed method can be recommended as a component in the production of commercial mineral turbine oil TP-22.

Positive effect: the proposed method allows, by improving the quality of used oils, to increase the resource of commercial oils, reducing the amount of used oils discharged to landfills. The advantage of the selective purification method chosen in this method is the possibility of implementing the process in a closed cycle mode.

Sources of information

1. Article:

Pykhalova, N.V., Makarova, D.A., Tleugaliev, D.R., Sultanov, T.Kh. A method for restoring the properties of used oils. All-Russian interdisciplinary scientific conference "Science and Practice - 2020" (Astrakhan, October 19-30, 2020) materials. - Astrakhan: ASTU Publishing House, 2020. - Access mode: 1 CD disk - State No. registration 0322100459.

2. Article:

Pykhalova, N.V., Tleugaliev, D.A. The method of regeneration of used mineral oil. All-Russian scientific conference of the faculty of the Astrakhan State Technical University (62PPS), Astrakhan: ASTU Publishing House, 2018. - Access mode: 1 CD - disk - state number. registration 0321803357 (prototype).

Claims (1)

A method for regenerating used mineral oils that do not contain additives by selective purification with N-methylpyrrolidone at a temperature not exceeding 90 ° C, settling until a phase boundary appears, separating the extract solution from the purified oil solution, followed by regeneration of N-methylpyrrolidone from the extract solution by distillation, characterized in that the regeneration of N-methylpyrrolidone from a solution of purified oil is carried out by washing, which includes diluting the solution of purified oil with water in an amount of 100-110 wt. % with respect to the purified oil solution, stirring for 5 min, settling for 20 min, separation of the purified oil from the aqueous solution of N-methylpyrrolidone, drying of the purified mineral oil by evaporating water at a temperature not exceeding 90 ° C in vacuum, dehydration of N- methylpyrrolidone by evaporating water for reuse in the selective purification process.