RU2802284C1 - Method for determining the content of oils in petroleum and petroleum products - Google Patents

Abstract

FIELD: analytical chemistry.

SUBSTANCE: method for determining the content of oils in petroleum and products of its processing consists in isolating asphaltenes from the initial sample of petroleum or petroleum product by precipitating them with petroleum ether, settling the solution in a place protected from light, followed by filtering the settled solution, evaporating the remaining filtrate to a minimum volume, and further sorption of resins by passing the solution through an adsorption column filled with aluminum oxide, evaporating the remaining solution to a minimum volume, dissolving it in an acetone-toluene mixture at a ratio of 35:65, extracting paraffins by freezing the mixture at minus 20°C and separation of paraffins by filtration on a cold filter and washing with hot toluene into a flask, characterized in that the remaining acetone-toluene solution is evaporated on a rotary evaporator, dried in an oven at 105°C to constant weight and determine the oil content by the formula: М = m₁/m₂⋅100%, where m₁ is the oil sediment weight, g; m₂ is the weight of the original sample, g.

EFFECT: expansion of methods for highly accurate and reliable determination of the content of oils in petroleum products, as well as in petroleum-containing deposits with a high content of resinous substances and paraffins, simplifying the method relative to known methods, reducing time, and therefore increasing its profitability implementation, as well as the possibility of a comprehensive assessment of the petroleum composition.

2 cl, 4 tbl, 5 ex

Description

The invention relates to analytical chemistry, namely to methods for determining the content of oils in oil and oil products and can be used in laboratories of oil companies, oil and oil products pipeline transport companies, research laboratories.

By chemical composition, petroleum oils are a mixture of hydrocarbons with a molecular weight of 300-750 amu, containing 20-60 carbon atoms in the molecules. Base oils consist of groups of isoparaffin, naphthene-paraffin, naphthene-aromatic and aromatic hydrocarbons of varying degrees of cyclicity, as well as heteroorganic compounds containing oxygen, sulfur and nitrogen. It is organoelement compounds (mainly oxygen-containing) that are the basis of the resins contained in base oils. The chemical composition of base oils and the structure of their constituent hydrocarbons are determined both by the nature of the processed raw materials and by the technology of its processing.

In accordance with the areas of application, oils are divided into lubricating and special-purpose oils. Lubricating oils are used in almost all areas of technology, depending on the purpose. Special oils serve as working fluids in hydraulic transmissions, as an electrical insulating medium in transformers, capacitors, cables, oil switches, and are used in the preparation of greases, additives, etc.

Oil from different fields has different chemical, physical properties and chemical composition, therefore, in order to choose the correct method of oil refining, to draw up material balances of some processes, it is necessary to know the composition of oil and oil products, including oils.

In addition, the shortage of fossil hydrocarbon raw materials leads to the need to deepen the processing of oil residues (processing of bituminous rocks, fuel oil) in order to obtain lubricating oils. Therefore, the determination of the oil content in fuel oil, tar, bitumen is no less important in determining the further processing of these petroleum products. But there are no methods for such definitions.

The method for determining the group composition of bitumen, fuel oil is based on a different ratio of the components that make up their composition to solvents and consists in dissolving a sample of a substance in an organic solvent, followed by determining the mass of the filtered and dried residue.

One of the most well-known methods for determining the content of oils in petroleum products is [GOST 11244-2018. Oil. Method for determining the potential content of distillate and residual oils]. The essence of this method is distillation of oil into fractions depending on the boiling point, dewaxing with a mixture of methyl ethyl ketone-toluene or acetone-toluene by heating in a water bath to 50-60ºС, followed by cooling the mixture to minus 33ºС, deasphalting with isopentane or petroleum ether and adsorption separation of the resulting fractions and residues on silica gel, sequential mixing of individual groups of hydrocarbons and determination of physicochemical parameters in the resulting mixtures. The disadvantage of this method is its high labor intensity, the duration of the process, the need to use a large number of reagents, equipment, and highly skilled operator. But most importantly, it is applicable only to oil, and is not applicable to other petroleum products, especially waste products.

In the literature [Shlogova V.E., Kozhevnikova V.A. Determination of the content of asphalt-resinous substances in oil / Proceedings of the XVII International Scientific and Practical Conference. prof. L.P. Kulev. P.630-631] describes a method for determining oils in oil, based on a method taken from [GOST 11858-06 Method for determining the content of asphalt-resinous substances], a sample of oil was diluted with a solution of petroleum ether, defended in a dark place, the precipitate containing asphaltenes was separated from the filtrate, the resulting deasphalted oil was passed through a silica gel column to precipitate resins, and the oil concentrate was washed out with a mixture of petroleum ether and benzene. The solvent was evaporated on heating, and the amount of oils in the sample was counted from the precipitate. This method can hardly be considered reliable, since it misses the content of paraffins in the oil sample. And in the GOST itself, to which the authors refer, the methodology for determining oils is not indicated at all.

Another well-known method is [GOST 9090 Petroleum paraffins. Method for determination of oil content]. The sample is dissolved in methyl ethyl ketone with heating, then cooled to minus 32°C to precipitate paraffin and filtered. The oil content is determined by evaporating the methyl ethyl ketone and weighing the residue. The disadvantage of this method is its applicability only for petroleum paraffins with a melting point above 30°C and a mass fraction of oil of not more than 15%. In addition, the reproducibility of the method reaches 11% of the arithmetic mean.

According to the well-known method for determining the content of paraffin in bitumen [GOST 17789-72 "Petroleum bitumen. Method for determining the content of paraffin "], which allows you to sequentially remove solid asphaltenes, paraffins and resins from petroleum products, a sample of bitumen weighed with an accuracy of 0.01 grams is placed in a container and dissolved in toluene while heated in a water bath and stirred. To precipitate asphaltenes, a 40-fold amount of petroleum ether is added to the resulting solution of bitumen in toluene and placed in a dark place for 24 hours. The settled solution is filtered carefully, without stirring, through a double “white tape” filter. The precipitate is washed in several steps on the filter with petroleum ether. Most of the solvent is distilled off from the flask with the filtrate until 20-30 ml of the concentrate is obtained and poured into an adsorption column filled with aluminum oxide and the sorbent is washed several times with the solvent. Petroleum ether is distilled off from the resulting desorbed solution, the residue in the flask is dissolved in 50 ml of an acetone-toluene mixture, the resulting solution is cooled to minus 20°C. The cooled solution is filtered at minus 20°C through a porous filter and washed with hot toluene into a flask where paraffin precipitation took place. The acetone-toluene solution remaining after the removal of paraffin seems to be promising for determining the content of oils in petroleum products.

The objective of the invention is to develop a method for determining the content of oils in petroleum products and oily deposits, based on the method for determining the content of paraffins in bitumen, which allows, if necessary, to expand the known method, and in addition to oils, to comprehensively study oil for such indicators as the content of asphaltenes, paraffins, resins and fur . impurities.

The technical result of the invention consists in expanding the methods for highly accurate and reliable determination of the oil content in petroleum products, as well as in oil-containing deposits with a high content of resinous substances and paraffins, in simplifying the method relative to known methods, reducing time, and therefore increasing the profitability of its implementation, as well as in the possibility of a comprehensive assessment of the composition of oil.

The specified technical result is achieved by sequential removal of asphaltenes, resins, paraffins, mechanical impurities from the sample with the possibility of analyzing them by known methods, and further analysis of the oil content in the sample. To do this, a weighed sample of an oil product or asphalt, resin and paraffin deposits (ARPD) is treated with a solvent, the reaction mixture is settled in a dark place with further separation by filtration from the resulting reaction mixture of an undissolved precipitate containing asphaltenes, the resulting solution containing paraffins, resins and oils is evaporated on a rotary evaporator to a minimum volume, passed through an adsorption column (sorbent - aluminum oxide), resins remain on the sorbent, paraffins and oils in the solution. The resulting solution is evaporated on a rotary evaporator to a minimum volume, then dissolved in an acetone-toluene mixture, cooled at minus 20°C. The precipitate containing paraffins is filtered off, washed with a solvent, and the solution is transferred into a previously prepared flask, evaporated and dried at 105°C in an oven to constant weight. The content of oils (M) in the original sample (in%) is found by the formula:

M \u003d m ₁ /m ₂ ⋅ 100%,

where m ₁ - weight of oils, g; m ₂ is the weight of the original sample, g.

The method is carried out as follows.

A portion of the sample (crude oil, oil product, ARPD) was dissolved in 40 times the volume of petroleum ether and placed in a dark place for 16 hours. The settled solution was filtered carefully, without stirring, through a double blue ribbon filter. The precipitate was washed on the filter with petroleum ether in several steps. If necessary, determined the content of asphaltenes according to a known method [US Pat. RU 2777764, publication date 08/09/2022]. Most of the solvent was distilled from the flask with the filtrate to obtain 20-30 cm ³ of the concentrate, which was transferred to an adsorption column filled with aluminum oxide, and the sorbent was washed several times with the solvent. Petroleum ether was distilled off from the resulting desorbed solution, the residue in the flask was dissolved in 50 cm ³ of an acetone-toluene mixture (35:65), the resulting solution was cooled to minus 20°C. The cooled solution containing the precipitate was filtered at minus 20°C through a porous filter and washed with hot toluene into a flask where paraffin precipitation took place. If necessary, determined the content of paraffin and resins by known methods [US Pat. RU 2780759, publication date 09/30/2022; Pat. RU 2691958, publication date 06/19/2019]. The oils remain in the acetone-toluene solution. This solution, depending on the quantity, was evaporated on a rotary evaporator or on a sand bath, dried in an oven at 105°C to constant weight. The flask with precipitated oils was weighed, and by the difference between this weight and the weight of the empty flask, the weight of the separated oils was found directly. The relative content of oils (M) was calculated by the formula:

M \u003d m ₁ / m ₂ 100%,

where m ₁ is the weight of the sediment of oils in the flask, g; m ₂ - weight of the initial sample, g

The possibility of a specific implementation of the invention is confirmed by the following examples.

Example1.

A portion of oil brand "Vityaz" weighing 3.17 g was dissolved in 110-120 cm ³ of petroleum ether and placed in a dark place for 16 hours. The settled solution was filtered carefully, without stirring, through a double blue ribbon filter. The precipitate was washed on the filter with petroleum ether in several steps. Most of the solvent was distilled from the flask with the filtrate to obtain 20–30 cm ³ of the concentrate, which was transferred to an adsorption column filled with alumina and the sorbent was washed several times with the solvent. Petroleum ether was distilled off from the resulting desorbed solution, the residue in the flask was dissolved in 50 cm ³ of an acetone-toluene mixture, and the resulting solution was cooled to minus 20°C. The cooled solution containing the precipitate was filtered at minus 20°C through a porous filter and washed with hot toluene into a flask where paraffin precipitation took place. The remaining acetone-toluene solution containing oils was evaporated on a rotary evaporator and dried in an oven at 105°C to constant weight. The relative content of oils M, calculated by the formula:

M \u003d m ₁ / m ₂ 100%,

where m ₁ is the weight of the sediment of oils in the flask, g; m ₂ - weight of the initial sample, g

m ₁ \u003d 1.3187 g; m ₂ \u003d 3.17, M \u003d 41.6%.

To calculate the error and reproducibility of the results obtained, analogously to example 1, 4 more experiments were carried out. The results are presented in Table 1, which shows the values of the oil content in the studied samples of Vityaz oil with a relative error and reproducibility calculated according to GOST R ISO 5725-2-02 “Accuracy (correctness and precision) of measurement methods and results. The main method for determining the repeatability and reproducibility of a standard measurement method.

The value of the relative error ∆ _l , in %, for the proposed method was calculated by the formula:

∆ _l \u003d 1.96 R / 2.77,

where _∆l is the laboratory error, R is the reproducibility of the results.

Example 2

A portion of fuel oil brand M-100 weighing 2.26 g was dissolved in 80 - 90 cm ³ of petroleum ether and placed in a dark place for 16 hours. The settled solution was filtered carefully, without stirring, through a double blue ribbon filter. The precipitate was washed on the filter with petroleum ether in several steps. Most of the solvent was distilled from the flask with the filtrate to obtain 20–30 cm ³ of the concentrate, which was transferred to an adsorption column filled with alumina and the sorbent was washed several times with the solvent. Petroleum ether was distilled off from the resulting desorbed solution, the residue in the flask was dissolved in 50 cm ³ of an acetone-toluene mixture, and the resulting solution was cooled to minus 20°C. The cooled solution containing the precipitate was filtered at minus 20°C through a porous filter and washed with hot toluene into a flask where paraffin precipitation took place. Acetone - toluene solution was evaporated on a rotary evaporator, dried in an oven at 105ºС to constant weight. The relative content of oils M, calculated by the formula:

M \u003d m ₁ / m ₂ 100%,

where m ₁ is the weight of the sediment of oils in the flask, g; m ₂ - a portion of the initial sample,

m ₁ = 1.600 g; m ₂ \u003d 2.26 g, M \u003d 70.8%.

Table 2 presents the values of 4 more similar determinations of the oil content in the studied samples of M-100 fuel oil with a relative error and reproducibility calculated in the same way as in example 1.

Example 3

A portion of the tar weighing 1.37 g was dissolved in 50-55 cm ³ of petroleum ether and placed in a dark place for 16 hours. The settled solution was filtered carefully, without stirring, through a double blue ribbon filter. The precipitate was washed on the filter with petroleum ether in several steps. Most of the solvent was distilled from the flask with the filtrate to obtain 20–30 cm ³ of the concentrate, which was transferred to an adsorption column filled with alumina and the sorbent was washed several times with the solvent. Petroleum ether was distilled off from the resulting desorbed solution, the residue in the flask was dissolved in 50 cm ³ of an acetone-toluene mixture, and the resulting solution was cooled to minus 20°C. The cooled solution containing the precipitate was filtered at minus 20°C through a porous filter and washed with hot toluene into a flask where paraffin precipitation took place. Acetone - toluene solution was evaporated on a rotary evaporator, dried in an oven at and 105ºС to constant weight. The calculated relative content of oils was 57.4%.

Table 3 presents the values of 4 more similar determinations of the oil content in the studied samples of tar with a relative error and reproducibility calculated in the same way as in example 1.

Example 4

A portion of ASPO weighing 2.36 g was dissolved in 90-100 cm ³ of petroleum ether and placed in a dark place for 16 hours. The settled solution was filtered carefully, without stirring, through a double blue ribbon filter. The precipitate was washed on the filter with petroleum ether in several steps. Most of the solvent was distilled from the flask with the filtrate to obtain 20–30 cm ³ of the concentrate, which was transferred to an adsorption column filled with alumina and the sorbent was washed several times with the solvent. Petroleum ether was distilled off from the resulting desorbed solution, the residue in the flask was dissolved in 50 cm ³ of an acetone-toluene mixture, and the resulting solution was cooled to minus 20°C. The cooled solution containing the precipitate was filtered at minus 20°C through a porous filter and washed with hot toluene into a flask where paraffin precipitation took place. Acetone - toluene solution was evaporated on a rotary evaporator, dried in an oven at and 105ºС to constant weight. The relative content of oils was 12.90%.

Table 4 presents the values of 4 more similar determinations of the oil content in the studied samples of ARPD with a relative error and reproducibility calculated in the same way as in example 1.

Example 5

A sample of oil sludge weighing 1.36 g was dissolved in 40-45 cm ³ of petroleum ether and placed in a dark place for 16 hours. The settled solution was filtered carefully, without stirring, through a double blue ribbon filter. The precipitate was washed on the filter with petroleum ether in several steps. Most of the solvent was distilled from the flask with the filtrate to obtain 20–30 cm ³ of the concentrate, which was transferred to an adsorption column filled with alumina and the sorbent was washed several times with the solvent. Petroleum ether was distilled off from the resulting desorbed solution, the residue in the flask was dissolved in 50 cm ³ of an acetone-toluene mixture, and the resulting solution was cooled to minus 20°C. The cooled solution containing the precipitate was filtered at minus 20°C through a porous filter and washed with hot toluene into a flask where paraffin precipitation took place. The remaining acetone - toluene solution was evaporated on a rotary evaporator, dried in an oven at 105ºC to constant weight. The relative content of oils M, calculated by the formula:

M \u003d m ₁ / m ₂ ⋅ 100%,

where m ₁ is the weight of the sediment of oils in the flask, g; m ₂ - weight of the initial sample

m ₁ \u003d 0.0100 g; m ₂ \u003d 1.36 g, M \u003d 0.74%.

The calculated reproducibility of results in pure petroleum products (oil, fuel oil, tar) is from 5 to 10% of the arithmetic mean value, in ASPO - 10%.

Table 1

Reproducibility of Vityaz oil sample analysis results

No.
p/n Oil content in the sample, % Reproducibility
from the mean, R Error,
∆, % X ₁ X ₂ X _cf. │X ₁ -X ₂ │ 10 % 5 % R.10% R.5% 1 40.2 41.6 40.9 1.4 4.09 2.5 2.9 1.45 2 39.8 41.6 40.7 1.8 4.07 2.11 2.9 1.49 3 42.1 40.1 41.1 2.0 4.11 2.06 2.9 1.46 4 40.6 42.2 41.4 1.6 4.14 2.07 2.9 1.46 5 42.0 43.1 42.5 1.1 4.25 2.13 3.0 1.51 Average value 41.3 Result 41.3 ± ( 1.45 - 3.0)

table 2

Reproducibility of the results of the analysis of the sample fuel oil brand M-100

No.
p/n Oil content in the sample, % Reproducibility
from the mean, R Error,
∆, % X ₁ X ₂ X _cf. │X ₁ -X ₂ │ 10 % 5 % R.10% R.5% 1 67.18 64.24 65.71 2.94 6.57 3.29 4.65 2.33 2 70.8 65.40 68.10 5.4 6.81 3.41 4.82 2.41 3 69.0 71.09 70.05 1.09 7.0 3.50 4.95 2.48 4 70.78 73.22 72.0 1.22 7.2 3.60 5.09 2.55 5 68.57 66.43 67.5 1.07 6.75 3.34 4.78 2.36 Average value 68.68 Result 68.7±(2.33 -5.09)

Table 3

Reproducibility of tar analysis results

No.
p/p Oil content in the sample, % Reproducibility
from the mean, R Error,
∆, % X ₁ X ₂ X _cf. │X ₁ -X ₂ │ 10% 5 % R.10% R.5% 1 60.4 57.2 58.8 3.2 5.88 2.05 4.17 1.45 2 57.3 60.1 58.7 2.8 5.87 2.94 4.17 2.08 3 55.8 58.9 57.4 3.1 5.74 2.88 4.10 2.04 4 54.5 57.4 56.0 2.9 5.60 2.80 3.96 1.98 5 53.0 56.5 54.2 3.5 5.42 2.74 3.82 1.94 Average value 57.44 Result 57.44 ±( 1.94 – 4.17)

Table 4

Reproducibility of ARPD analysis results

No.
p/n Oil content in the sample,
% Reproducibility
from the mean, R Control standard Reproducibility
from the mean, R Control standard X ₁ X ₂ X _cf. │X ₁ -X ₂ │ 10 % │X ₁ - X ₂ │≤ R 5 % │Х ₁ - Х ₂ │≤R 1 2.44 2.64 2.54 0.2 0.25 Satisfactory 0.13 Not satisfied. 2 12.22 12.90 12.56 0.68 1.26 Satisfactory 0.63 Not satisfied. 3 0.67 0.74 0.7 0.07 0.07 Satisfactory 0.035 Not satisfied. 4 2.43 2.68 2.55 0.25 0.26 Satisfactory 0.13 Not satisfied. 5 0.76 0.69 0.73 0.07 0.073 Satisfactory 0.037 Not satisfied.

Claims (4)

1. A method for determining the content of oils in oil and products of its processing, which consists in isolating asphaltenes from an initial sample of oil or oil product by precipitating them with petroleum ether, settling the solution in a place protected from light, followed by filtering the settled solution, and evaporating the remaining filtrate to a minimum volume , and further sorption of resins by passing the solution through an adsorption column filled with alumina, evaporating the remaining solution to a minimum volume, dissolving it in an acetone-toluene mixture at a ratio of 35:65, isolating paraffins by freezing the mixture at minus 20 ° C and separating paraffins by cold filtration filter and rinsing with hot toluene into a flask, characterized in that the remaining acetone-toluene solution is evaporated on a rotary evaporator, dried in an oven at 105°C to constant weight, and the oil content is determined by the formula: M \u003d m ₁ / m ₂ ⋅ 100%, where m ₁ - oil sediment weight, g; m ₂ - weight of the original sample, g. 2. The method according to claim 1, characterized in that asphaltenes, paraffins, resins, fur can be determined from one sample of the oil product. impurities and oils.