RU2426116C1 - Method for determining secondary residual products of oil refining in mixed fuels - Google Patents

Abstract

FIELD: oil and gas industry. ^ SUBSTANCE: method is implemented with extraction of deposit by centrifugal separation of pre-diluted fuel, with its further subsequent washing with petroleum ether and toluol, determination of informative parameter as per calculation formula by using values of deposit masses before and after washing with solvents, determination of optical density of tar oil, analysed fuel and value of their mismatching, as per which the presence of thermocracking residues (TKR) (viscosity breaking residues (VBR)) in analysed fuel in amount of 0.05 to less than 2.0 wt % is estimated. ^ EFFECT: higher sensitivity and accuracy of analysis. ^ 3 ex, 3 tbl

Description

The invention relates to the field of research of liquid hydrocarbon fuels, mainly mixed fuels containing residual products of oil refining, boiler (fuel oil) and marine fuels, and can be used to control the quality of boiler fuel (fuel oil F5), as applied to its use in the Naval fleet (Navy), when choosing fuels for diesel engines on ships of economic entities and determining the possibility of long-term storage of fuels.

Mixed fuels from residual products may contain residual products of direct distillation of oil (fuel oil, tar) and secondary residual products of oil refining: residues of thermal cracking (OTK) and visbreaking (OVB). In accordance with GOST 10585, F5 fuel oil used in the Navy should be manufactured only with the involvement of residual products of direct distillation of oil in its composition. The remaining mixed fuels may contain both primary and direct residual residual products and secondary (destructive processes) residual products.

These compositional differences are due to significantly different conditions for the use of mixed fuels on ships of the Navy and on ships of economic entities. In the case of the use of mixed fuels on ships of the Navy, which are at sea for a long time or in reserve, the required continuous shelf life in tanks is 5-6 years. In other cases, where long-term storage is not required, additional rather sophisticated equipment is used to completely remove precipitation before fuel is supplied to the engine.

A feature of the secondary residual products of oil refining - OTK and OVB - is the increased content of asphalt-resinous substances (mainly asphaltenes) in the suspension in the fuel, prone to precipitation during storage and leading to increased carbon formation during combustion (T.N. Mitusova, I. A. Pugach, N. P. Averina. Chemistry and technology of fuels and oils, No. 2, 2001, p.6-7). The amount of asphaltenes in fuel oils of cracking processes (i.e., secondary - destructive - oil refining processes) in comparison with fuel oils obtained on the basis of direct distillation of oil (fuel oil F5) can differ by an order of magnitude or more (B.V. Losikov et al. Fuel for stationary and ship gas turbines. M., Chemistry, 1970, p.97).

The choice of mixed fuels containing residual products of direct distillation of oil is also important for vessels of economic entities, since the number of problems arising from this is significantly reduced, since precipitation requiring removal by mechanical means (wiping tanks) is not formed. With the content in the fuel of up to 2.0% of secondary residual products, the amount of precipitation is insignificant (due to the short shelf life of fuel on ships of economic entities) and relatively easily removable. (Operation of ship diesel power plants. Textbook for high schools, S.V. Kamkin, I.V. Woznitsky, V.F. Bolshakov and others. M .: Transport, 1996, p. 238-250).

The authors were faced with the task of developing a method for determining the secondary residual products of oil refining (OTC and OVB) in mixed fuels, which would meet the following requirements:

- increase the reliability of the results;

- improving the accuracy (sensitivity) of determining the quality control system (OVB) in mixed fuels, namely their detection when the content in the fuel is less than 2% of the mass .;

- a wider differentiation of fuels by the content of OTC (OVB) in them;

- be implemented on materials widely used in laboratory research and known domestic equipment.

An analysis of the scientific and technical literature and patent information sources revealed methods for determining indirect (secondary) residues of oil refining in fuels, based on the determination of their toluene equivalent (GOST R 50837.3-95 residual fuels. Determination of straightness. Method for determining toluene equivalent), xylene equivalent ( GOST R 50837.4-95 Residual fuels. Determination of straightness. Method for determining xylene equivalent) and "spot numbers" (GOST R. 50837.7-95. Residual fuels. Determination of straightness. Me odes determination of stability and compatibility spot). All these methods are characterized by low accuracy (reliability and reliability), since they are based on a visual (subjective) assessment of stains obtained from diluted fuels on paper. On them you can only qualitatively judge the straightness of fuels, and the methods contradict each other. The presence of OTK (OVB) in the fuel in the amount of tens of% of the mass. can show by these methods as their absence.

Closest to the claimed method, taken as a prototype, is a quantitative method for determining the secondary residual products of oil refining in mixed fuels by the difference in the mass of precipitation obtained by centrifuging the diluted fuel and washed initially with petroleum ether and then toluene, referred to the amount of the diluted mixture (patent No. 2368900 G01N 33/22, 06/06/2008)

This method involves the selection and preparation of a sample, mixing it with a distillate component to reduce the viscosity of the mixture to a value of (1.75 ± 0.05) mm ² / s at 100 ° C, pouring the required amount of the mixture into a pre-weighed m ₁ metal cuvette, fixing the weight of the cuvette with the mixture m ₂ , heating the mixture to 100 ° C, holding the cuvette with the mixture at this temperature for 50 minutes in an oven at a temperature of (105 ± 3) ° C, centrifuging this mixture at a temperature sufficient to preserve the melted paraffins in liquid form, draining the liquid part, mixing the residue remaining in the cuvette with petroleum ether, centrifuging the resulting solution, draining the liquid part, bringing the remaining precipitate in the cuvette to a constant mass m ₃ , separating asphaltenes from this precipitate, for which the precipitate is mixed with toluene, centrifuging, and the remaining toluene part is drained, the remaining in the cuvette, the precipitate is brought by drying to constant mass m ₄ , calculation of the information indicator "A" by mathematical dependence: A = (m ₃ -m ₄ ) / (m ₂ -m ₁ ) · 100% of the mass. and with a value of "A" ≤0.005% of the mass. judge the absence of secondary residual refined petroleum products in the analyzed fuel.

The disadvantage of this method is its relatively low sensitivity (from 2% wt. Or more) to the presence of OTK (OVB) in the fuel.

As experience shows the use of mixed fuels (fuel oil F-5 according to GOST 10585) on ships, with such a sensitivity of the method, in one full refueling (weighing up to 10,000 tons), fuel oil can contain up to 200 tons of OTC (OVB). The minimum fuel balance on the ship is 40% of the refueling mass, and therefore, on the ship during storage for several years, up to 80 tons of Quality Control Department (OVB) can be present in the fuel composition. Storage of fuel (in the amount of full refueling) on reserve ships can be 6 or more years. During this time, the amount of asphaltenes measured in hundreds of kilograms or more may precipitate. The task of removing asphaltenes, which are sticky in the sediment, is very time-consuming (collecting with trays, scrapers, wiping the surfaces of the tanks with rags moistened with diesel fuel, and then burning it).

In this regard, the authors of the method continued research to improve the prototype method in terms of increasing sensitivity to the presence of OTC (OVB) and developed a more accurate way to detect these products in fuel. At present, the process of visbreaking in oil refining is increasingly used for the production of fuel oils of grades "40" and "100" according to GOST 10585 and there is a real threat of OTK (OVB) getting into fuel oil F-5.

The technical result of the invention is improving the accuracy (sensitivity) of the method.

The specified technical result is achieved by the fact that in the known method for determining the secondary residual products of oil refining in mixed fuels, including sampling and preparing the sample, mixing it with a distillate component until the mixture viscosity is equal to (1.75 ± 0.05) mm ² / s at 100 ° C, bay required amount of the mixture in a pre-weighed metal ₁ m cuvette cuvette weight fixation with a mixture of m _2, heating the mixture in the cell to a temperature of 100 ° C, the cell extract with the mixture for 50 minutes in an oven at a temperature dostat ary to maintain melt paraffin in liquid form, draining the liquid portion, stirring was remaining in the cake cuvette with petroleum ether, centrifuging the obtained solution, pouring the liquid portion, bringing remaining in the cell pellet drying to constant mass m _3, the separation of this precipitate asphaltenes, which precipitate was stirred with toluene, centrifuged, the liquid decanted toluene part, bringing the remaining cell pellet in drying to a constant mass m _4, index calculation information "a" for the mathematical isimosti A = (m -m _{3 4)} / (m ₂ -m ₁₎ · 100 wt.%, according to the invention at the value of index "A"<0.005% by weight. additionally determine the optical density (OD) of the merged in the separation of the asphaltenes of the liquid toluene part, set the OD value of the tar, find ΔOP and with ΔOP values from 0.003 to 0.175 units. conclude that the analyzed fuel contains secondary residual products of oil refining in the amount of M,% mass., determined by the expression 0.05≤M≤1.99.

The main operational parameters of the test and the sequence of methods selected based on the following provisions:

- the viscosity of the mixture (1.75 ± 0.05) mm ² / s at 100 ° C, to which the analyzed sample is diluted with a distillate component before centrifugation, is the viscosity of the statistically lowest viscosity commercial sample of F5 fuel oil in accordance with GOST 10585, made without the use of a depressant additive. With the beginning of the use of depressant additives, a greater amount of straight-run oil refining residues are involved in F5 fuel oil and, therefore, the viscosity of F5 fuel oil with a depressant additive is higher. The viscosity of the remaining samples of used commercial marine mixed fuels is significantly higher. At the same time, dilution of mixed fuels to the indicated viscosity (1.75 ± 0.05) mm ² / s at 100 ° C allows them to be tested under the same conditions, i.e. subsequently to differentiate fuels according to the content of OTK and OVB;

- weighing the empty cuvette (m ₁ ) and the cuvette filled with the mixture (m ₂ ), allows to determine the mass of the mixture taken for centrifugation;

- heating the mixture in a cuvette on a tile to 100 ° C and then holding it for 50 minutes in an oven at a temperature of (105 ± 3) ° C ensures the melting of the highest melting solid paraffins present in any mixed fuel and their long-term storage at room temperature temperature in molten form. (VB Losikov et al. Fuels for stationary and ship gas turbines. M., Chemistry, 1970, p.69);

- centrifugation of the mixture (as an option 70,0000 g) at a frequency (4000 ± 100) min ^-1 of the centrifuge rotor TsLS-3 provides the precipitation from mixed fuels (A.A. Gureev, E.P. Seregin, V.S.Azev Qualification test methods for petroleum fuels. M., Chemistry, 1984, p.192);

- the duration of centrifugation (as an option 40 min) ensures the precipitation of the precipitate from the mixture at its low viscosity (1.75 ± 0.05) mm ² / s at 100 ° С (in comparison with commodity samples of mixed fuels);

- the temperature (60 ± 2) ° C of the centrifugation of the mixture ensures that the solid paraffins that are present in the mixed fuels melted at 100 ° C are in liquid form and removed together with the rest of the liquid from the cuvette;

- mixing the precipitate in a cuvette with petroleum ether (as an option with 15 cm ³ ) ensures the dissolution of the mixture residues in it and their subsequent removal during centrifugation discharge to isolate the precipitate (as an option (3000 ± 100) min ^-1 for 10 min;

- drying the residue remaining in the cuvette in the oven (as an option at 100 ° C, which is 30 ° C higher than the boiling point of petroleum ether, for 30 minutes) and then bringing the residue to a constant weight in the drying oven, it is possible to obtain a stable precipitate (m ₃ );

- mixing the remaining precipitate with toluene (as an option with 15 cm ³ ) ensures the dissolution of the asphaltenes contained in the precipitate, their transfer to the liquid part of the mixture and their subsequent removal during discharge after centrifugation to separate the precipitate (as an option (3000 ± 100) min ^-1 within 10 min);

- drying in the drying cabinet of the precipitate remaining in the cuvette (as an option at 140 ° С, which is 30 ° С higher than the boiling point of toluene, for 30 min) and subsequent adjustment of the precipitate to a constant mass at this temperature allows to obtain a stable precipitate (m ₄ );

- determination of the value of the information indicator "A" from the mathematical dependence A = (m ₃ -m ₄ ) / (m ₂ -m ₁ ) · 100% of the mass .;

ед.) слитой жидкостной толуольной части, количество которой (14,6 см³) намного больше, чем необходимо (1,5 см³) для измерения оптической плотности;- determination at a value of A <0.005% of the mass. optical density OP (as an option - on the FEK-56M instrument with a 3 mm cuvette and filter No. 8 - symbol

units) of the drained liquid toluene part, the amount of which (14.6 cm ³ ) is much larger than necessary (1.5 cm ³ ) for measuring the optical density;

- the establishment of a numerical (threshold) value of the OD indicator of tar, which means the absence of secondary residual products of oil refining in mixed fuel;

- determination of the mismatch ΔOP of the analyzed fuel and tar corresponding to the content of the quality control system (OVB) in the fuel (M,% mass.) from 0.05 to 1.99.

The essence of the claimed method lies in the fact that mixed fuels containing OTC and OVB, in contrast to fuels containing only primary (straight-run) oil refining residues (fuel oil, tar), contain a significantly larger amount of asphaltenes. In turn, asphaltenes have a density of up to 1100 kg / m ³ , which is greater than the density of the mixed fuels themselves, as a result of which they are prone to precipitation during storage. Dilution of fuel with a distillate component significantly increases this difference (the density of diesel fuel from typical oils is about 835 kg / m ³ ), and the effect of centrifugal forces on asphaltenes during centrifugation facilitates their accelerated separation from diluted fuels into sediment. The specified difference in the number of asphaltenes in the primary and secondary residual products of oil refining is detected by the claimed method.

To confirm the significance of the operational parameters and the necessary sequence of methods of the claimed method, fuel samples were prepared (table 1), covering their entire range (in viscosity), three of which (samples 1-3) contain only primary (straight-run) oil refining products (sample No. 3 - fuel oil F5), and the remaining samples (4-14) also contain secondary residual products of oil refining (the remains of thermocracking or its improved version - visbreaking, respectively, OTC and OVB).

When conducting a study of the prepared samples, it was found that the optical density value of the heaviest direct oil distillation residue - tar (table 1, column 1, line 2 and table 2, column 10, line 2) is 0.007 units. If there is 0.05% of the mass in the analyzed fuel. OTC (OVB) OD is 0.010 units, which exceeds the OD of tar, and the content itself is 0.05% of the mass. secondary residual oil refining products is the sensitivity of the method (table 1, column 9, line 4 and table 2, column 10, line 9). With an increase in the content of OTC (OVB) in the fuel, their OP gradually increases, which provides, in comparison with the prototype, an increase in the differentiation of fuels by the content of OTC (OVB) in them due to the additional identification of samples containing from 0.05 to 1.99% of the mass. OTK (OVB).

The threshold optical density value, which means the absence of OTC (OVB) in the analyzed fuel, was determined using sample No. 2 (table 1), i.e. tar (straight run product), the content of asphaltenes in which is higher than in fuel oil (also straight run product). According to the results of his test (table 2), it was found that the threshold value, which means the absence of OTK (OVB) in the fuel (fuel component), is an OD value of 0.007 units. (table 2, column 10, line 2). The sensitivity of the method for the content of OTK (OVB) in the fuel was determined by the OD values of samples 9 and 10 (table 1) and the results of their tests (table 2, column 10, lines 9 and 10). These results showed that the secondary residual products are found in the fuel of the claimed method with their content from 0.05 to 1.99% of the mass. (samples 9 and 4).

The application of the invention will increase the sensitivity of detection of secondary residual products of oil refining in fuel from 2.0 (prototype) to 0.05 wt.%, Which will significantly reduce the costs associated with cleaning the fuel systems of ships from asphaltene precipitates contained in the Quality Control Department.

Table 1 The component composition of the prepared (artificially) fuel samples for testing by the claimed method Type of components The composition of the fuel samples,% mass. one 2 3 four 5 6 7 8 9 10 eleven 12 13 fourteen Primary (straight-run) residual oil refining products: - fuel oil one hundred - 75 - 97.5 - 85 76.9 77 77.6 90 80 fifty - - tar - one hundred - 77.01 - 62 - - - - - - - 17 Secondary (indirect indirect residual products of oil refining): - the remainder of thermocracking (OTC) one - Visbreaking balance (OVB) - - - 1.99 1,5 - one 0.1 0.05 0.04 10 twenty fifty 80 Distillate product (diesel fuel for marine diesel engines according to GOST 305) 25 21 one 37 fourteen 23 22.95 22.86 3

The method is implemented as follows.

Example 1

A sample of mixed fuel (sample 3) with a viscosity of 7.8 mm ² / s at 100 ° C in an amount of 72 g is taken, to which 216 g of diesel fuel for marine diesel engines is added according to GOST 305. 288 g of a diluted mixture of sample 3 with a viscosity of 1 is obtained , 76 mm ² / s at 100 ° C. The indicated viscosity of the mixture corresponds to the claimed method (1.75 ± 0.05) mm ² / s.

The mass of the empty metal cuvette is determined (m ₁ ): m ₁ = 62.5215 g. The required amount of the prepared mixture is poured into the cuvette and the mass of the cuvette with the mixture is determined (m ₂ ): m ₂ = 132.5215 g. The cuvette with the filled mixture is heated on the tile to 100 ° C, place it in a drying oven, previously heated to a temperature of (105 ± 3) ° C, and stand the cuvette with the mixture at this temperature for 50 minutes.

After 50 minutes, remove the cuvette with the mixture from the oven and place it in the centrifuge rotor cavity, the rotor chamber of which is preheated (and subsequently maintained) to a temperature of (60 ± 2) ° С. The centrifuge rotor (in order to avoid beating of its shaft) is balanced, for which a load is placed in the opposite rotor socket (as an option, a second cell with fuel, differing in mass from the first by no more than 0.02 g).

The balancing of the rotor is performed before each subsequent inclusion of its rotation. The rotor is turned on and the mixture is centrifuged for 40 minutes. After 40 min of centrifugation, the liquid part of the mixture is drained from the cuvette, 15 cm ^{3 of} petroleum ether is poured into the cuvette, mixed with sediment, centrifuged (already without heating the rotor chamber) at (3000 ± 100) min ^-1 for 10 min, and then drained liquid part (petroleum ether with the remains of the mixture).

The cuvette with the remaining precipitate is installed in the oven, preheated to 100 ° C, for 30 minutes, after which the cuvette with the precipitate is removed from the oven, cooled to room temperature, weighed, and the cuvette with the precipitate is brought up (using the indicated drying, cooling, and weighing techniques) to constant weight m ₃ : m ₃ = 62.5259.

Pour in a cuvette with a precipitate 15 cm ^{3 of} toluene, mix it with a precipitate (to dissolve the asphaltenes present in the precipitate), centrifuge the resulting solution for 10 min at (3000 ± 100) min ^-1 to separate the precipitate and the liquid part (toluene-asphaltene solution), the liquid part from the cuvette is drained, it is stored to determine its optical density, the cuvette with the precipitate is installed in the oven, preheated to 140 ° C for 30 minutes, after which the cuvette with the precipitate is removed from the oven, cooled to room temperature, at outweighs cuvette and adjusted with the precipitate (drying methods indicated - Cooling - weighting) to constant mass m _4: m ₄ = 62.5234 g

Having received the mass values m ₁ m ₂ , m ₃ and m ₄ , calculate the value of the information indicator "A" by the formula:

the value of the information indicator "A" for sample 3 was:

The resulting value of 0.0036% of the mass. information indicator "A" is less than its threshold value (0.005% by mass), and therefore, the optical density of the fused liquid toluene part is determined, which amounted to OD = 0.003 and did not exceed the value selected as a threshold value (0.007 units), which means the absence of secondary residual refined petroleum products in the sample. The reliability of the conclusion is confirmed by the component composition of sample 3 (table 1), which contains 75% of the mass. fuel oil (straight run product) and 25% of the mass. diesel fuel (distillate product).

Example 2

A sample of sample No. 4 is taken in an amount of 47.8 g, in which 1.99% of the mass is present. secondary residual product of oil refining (OTC) and add to it 240.2 g of diesel fuel, obtaining 288 g of a mixture with a viscosity of 1.75 mm ² / s at 100 ° C, which meets the requirements of the claimed method.

Then carry out operations similar to those described in example No. 1, and get fixed values: m ₁ = 62.5215 g; m ₂ = 132.5215 g; m ₃ = 62.5292 g; m ₄ = 62.5258 g; OD = 0.182 units; and the calculated value "A", which is equal to 0.0048% of the mass. That is less than the threshold value of this indicator (0.005% of the mass.). The value of the indicator "A" concludes that the fuel does not have secondary residual products in the amount of 2.0% of the mass. and more. By the value of the OD index, which amounted to 0.182 units, it is concluded that secondary residual products of oil refining are present in the fuel, since the obtained OD value exceeded its threshold value (0.007 units), which is confirmed by the composition of sample No. 4 containing 1.99% mass OVB.

Example 3

Sample No. 9 is taken at a viscosity at 100 ° C of 10.0 mm ² / s in an amount of 63.36 g, to which 224.64 g of diesel fuel for marine diesel engines L-62 is added according to GOST 305. 288 g of a diluted mixture with viscosity at 100 are obtained. ° C 1.76 mm ² / s. The specified viscosity meets the requirement of the proposed method (1.75 ± 0.05) mm ² / s at 100 ° C.

Perform operations similar to those described in example 1.

The fixed values provided for by the method are obtained: m ₁ = 62.5215 g; m ₂ = 132.5215 g; m ₃ = 62.5240 g; m ₄ = 62.5210 g; OD = 0.010 units and according to these data, the estimated value of the indicator "A", which is equal to: A = [(m ₃ -m ₄ ) / (m ₂ -m ₁ )] · 100% = 0.0043% of the mass. This value is less than the threshold value of the indicator "A" (0.005% mass.), And therefore determine the value of the indicator OP, which turned out to be equal to 0.010 units, which exceeds its threshold value (0.007 units) and means the presence of secondary residual products in the fuel (in the amount of 0.05% of the mass.). The reliability of this conclusion is confirmed by the composition of sample 9 (table 1), containing 0.05% of the mass of OVB.

The test results of the remaining prepared (table 1) samples of mixed fuels according to the claimed method are shown in table 2.

As can be seen from the test results (tables 1 and 2), the presence of secondary residual products of oil refining in mixed fuels is reliably detected by the indicator "A" in the fuel samples when their content in the original analyzed mixed fuel in an amount of not less than 2.0% of the mass. (table 1 - the number of secondary residual products in samples 11-14 and the test results of these samples (table 2, column 9, lines 11-14), and the information indicator “A” for these samples varies widely (from 0.1928 up to 1.9400), i.e., more than an order of magnitude.

This allows you to differentiate well mixed fuels according to the information indicator "A" relative to the content of OTK and OVB in the amount of 2% of the mass. and more. According to the OD optical density index, an additional 6 more samples (Nos. 4–9) of fuels containing secondary residual products of oil refining in an amount of 0.05 to 1.99% wt.% Were revealed, which is confirmed by their component composition (table 1) and their test results (table 2, column 10, lines 4-9). In all these samples, the optical density index exceeds the threshold value (0.007 units) and means the presence of secondary residual products in the fuel in an amount from 0.05 to 1.99% by weight.

At the same time, a good differentiation of these fuels is also observed (OD for them varies from 0.010 to 0.182 units - table 2, column 10, lines 4-9), and by the content of secondary residual products in them from 0.05 to 1.99% of the mass . (table 1, samples 4-9). In order to increase these products in them, the samples are arranged as follows: Nos. 9, 8, 7, 6, 5, and 4, for which the optical density is 0.010, respectively; 0.034; 0.110; 0.110; 0.134 and 0.182 (table 2, column 10, lines 9, 8, 7, 6, 5 and 4) and exceed the threshold value of this indicator (0.007 units), which means the presence in the fuel of secondary residual products in the amount of 0.05% of the mass . and more, and corresponds to the actual content of the AEC in them: 0.05; 0.1; 1.0; 1.0; 1.5 and 1.99% of the mass. accordingly (table 1). From the same data, it follows that with the same content of OTC or OVB in the fuel (table 1, samples 6 and 7, columns 6 and 7), the value of the OD index (table 2, column 10, lines 6 and 7) is the same, which allows us to establish a single value of optical density (OD> 0.007 units), which means the presence in the fuel of secondary residual products of oil refining both in the quality control system and in the OVB in the amount of 0.05% of the mass. and more.

The discrepancy between the OD values for the tar (OD = 0.007) and the analyzed fuel, which means the presence in it of secondary residual products of oil refining in an amount of 0.05 to 1.99% by weight, is from 0.003 to 0.175 units, because when the content in fuel 0.05% of the mass. OD is 0.010 units. (the mismatch is 0.010-0.007, i.e. 0.003 units), and when they are contained in an amount of 1.99% of the mass. - 0.175 units (0.182 - 0.007 = 0.175).

The claimed method tested a number of commodity mixed fuels, both not containing (according to passport data), and containing OTC and / or OVB, although the exact content in some of them OTK (OVB) is not given. The test results of these fuels for the presence in them of secondary residual products of oil refining according to the prototype and the claimed method are shown in table 3.

From the data shown in table 3, it follows that according to the prototype method, only 4 samples (No. 4-7, columns 5 and 6, rows 4-7) of 11 samples revealed the presence of quality control systems (FFA), which does not correspond to the passport data. According to the claimed method, the presence of secondary residual products was detected in 8 samples (No. 4-11, columns 13-15, lines 4-11) of fuels, which corresponds to the passport data.

The identification of an additional 4 samples (table 3, samples 8-11, columns 13 and 15, rows 8-11) of fuels containing secondary residual products of oil refining became possible due to the additional method for determining the optical density of the toluene-asphaltene mixture obtained by washing the precipitates released by centrifugation from fuels. For all these samples, the mismatch of their OD with the OD of the tar is from 0.018 (for sample 8) to 0.168 (for sample 11), which falls within the stated limits of this mismatch (from 0.003 to 0.175 units) and means the presence of secondary fuels in these fuels residual products of oil refining in an amount of from 0.05 to 1.99%% of the mass.

At the same time, there is a good differentiation of these fuels in terms of OP, which varies from 0.025 to 0.182 units for them. when you change the content in them of the secondary residual products of oil refining from 0.05 to 1.99% of the mass. (respectively, samples 9 and 4 - tables 1 and 2).

According to the presence or quantity (in the presence of OTC (OVB)) contained in the OTC (OVB) fuels, the samples are well differentiated and arranged (in ascending order) in the following order (according to tables 1, 2, 3):

No. 1-3 - do not contain OTC (OVB);

Nos. 8, 9, 10 and 11 contain (% wt.) OTC (OVB) in amounts from 0.05 to 0.1, respectively; from 0.1 to 1.0; from 1.0 to 1.5 and from 1.5 to 1.99.

The data shown in table 3 for commodity mixed fuels (column 14, samples 1-6), for which in the passport data (column 4) the content (or absence) of OTC (OVB) is given, falls within the given limits. According to the OP (column 13), samples 1–3 of the Quality Control Department (OVB) are absent, since the value of this indicator is from 0.002 to 0.004 units for them, which is less than the threshold value of this indicator (0.007 units), which means the absence of secondary residual products in fuel. The content of OTC (OVB) in samples 4, 5, 6 falls within the given limits for indicator “A” and confirms the reliability of the method. The magnitude of the OP confirms the presence (and quantity) in the fuel OTK (OVB) when it is within the scale of the device. The content of OTC (OVB), equal to 34.5%, corresponds to an OD value of 2.935 units. This content corresponds to the value of the indicator "A" (A = 0.9167).

Detected by the invention, the content of OTK (OVB) in fuels (method sensitivity) is 0.05% by mass, which is 40 times less than that of the prototype, i.e. It has a significant advantage over the prototype in sensitivity. Accordingly, for such a fuel sample, both the amount of asphaltenes precipitating and the complexity of their removal when cleaning ship tanks will decrease. With the help of the invention, if necessary, in special circumstances (when naval ships are far from their bases) from the available on-site mixed fuels, one can select those that do not contain (within the sensitivity of the method) residual products of secondary oil refining, and prepare them (by adding diesel fuel with a flashpoint of more than 60 ° C) low-viscosity naval fuel oil F5, i.e. fuel oil, which is the only one approved for use on ships of the Navy.

The identification among commodity mixed fuels of those that do not contain OTC and OVB (within the sensitivity of the method) allows them to be given preference to business entities during the operation of ships, and also, if necessary, bookmark them for longer than usual , storage periods (in reserve).

The application of the invention allows due to the totality of the claimed techniques to achieve:

- increase the reliability of test results;

- improving the accuracy (sensitivity) of determining the quality control system (OVB) in mixed fuels;

- a wider differentiation of mixed fuels by their content of secondary residual products of oil refining due to the identification of samples containing OTC (OVB) in an amount of from 0.05 to 1.99% of the mass .;

- be implemented on materials widely used in laboratory research and known domestic equipment.

Claims (1)

A method for determining the secondary residual products of oil refining in mixed fuels, including sampling and preparing a sample, mixing it with a distillate component until a mixture viscosity of (1.75 ± 0.05) mm ² / s at 100 ° C is reached, filling in the required amount mixture into a pre-weighed metal ₁ m cuvette cuvette weight fixation with a mixture of m _2, heating the mixture in the cell to a temperature of 100 ° C, the cell extract with the mixture for 50 minutes in an oven at a temperature sufficient to maintain a melt paraffin in liquid form , Draining the liquid portion, stirring was remaining in the cake cuvette with petroleum ether, centrifuging the obtained solution, pouring the liquid portion, bringing remaining in the precipitate cuvette drying to constant mass m _3, the separation of this precipitate asphaltenes to precipitate was stirred with toluene, centrifuged, decanted the liquid toluene part, bringing the residue remaining in the cuvette by drying to a constant mass of m ₄ , calculation of the information indicator “A” by mathematical dependence: A = (m ₃ -m ₄ ) / (m ₂ -m ₁ ) · 100 wt.%, differing the fact that with the value of the indicator "A"<0.005 wt.% additionally determine the optical density (OD) of the merged in the separation of the asphaltenes of the liquid toluene part, set the OD of the tar, find ΔOP and at values of ΔOP from 0.003 to 0.175 units make a conclusion about the presence in the analyzed fuel of secondary residual products of oil refining in the amount of M, wt.%, determined by the expression 0.05≤M≤1.99.