RU2368900C1 - Method of detecting secondary residual products from refining oil in mixed fuels - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to analysis and controlling quality of liquid hydrocarbon fuels and determination of possibility of prolonged storage of fuel. The method involves taking and preparing a sample, mixing it with a distillate component, heating the mixture to 100°C and evaluating the deposit. The sample is mixed with the distillate component before viscosity of the mixture reaches (1.75+0.05) mm²/s at 100°C. The required amount of mixture is poured into a pre-weighed metallic vessel m₁, and the weight of the vessel with the mixture m₂ is recorded. After heating the mixture to 100°C the vessel with the mixture is kept in a drying chamber for 50 minutes at (105+3)°C. This mixture is centrifuged at temperature sufficient for keeping molten paraffins in liquid state. The liquid part is poured out. The deposit remaining in the vessel is mixed with petroleum ether, after which the obtained solution is centrifuged. The liquid part is poured out and the deposit remaining in the vessel is dried to a constant mass m₃. Asphaltenes are then separated from this deposit, for which the deposit is mixed with toluene, centrifuged, the liquid toluene part is poured out and the deposit remaining in the vessel is dried to a constant mass m₄. After that the information indicator is calculated form the given ratio and if A < 0.005 wt %, there are no secondary residual products from refining oil in the analysed fuel.

EFFECT: more accurate detection, as well as possibility of differentiating mixed fuels.

2 ex, 3 tbl

Description

The invention relates to the field of research of liquid hydrocarbon fuels, mainly mixed fuels containing residual oil refining products - boiler (fuel oil) and marine fuels, and can be used to control the quality of boiler fuel (fuel oil F5) in relation to its use in the Navy ( 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 residual products (direct distillation) and secondary residual oil refining products (products of destructive processes).

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 Navy ships that 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 an increased content of asphalt-resinous substances (mainly asphaltenes) in them, which are in suspension in the fuel, prone to precipitation during storage and leading to increased carbon formation during combustion (T.N. .Mitusova, I.A. Pugach, NP 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) processes of oil refining) 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 (Operation of marine diesel power plants. Textbook for high schools. SVKamkin, IVVoznitsky, V .F. Bolshakov et al. - 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:

- reliability and reliability of the results;

- the possibility of differentiation of fuels according to the data;

- implementation on materials widely used in laboratory research and known equipment.

An analysis of the scientific and technical literature and patent information sources revealed a method 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). In this method, three mixed fuel samples (2 g each) are taken, each of which is mixed with 10 cm ^{3 of a} solution of toluene in n-heptane, in which the toluene content is 40, 50 and 60 vol.%), Respectively.

Apply (after mixing) with a medical pipette to the membrane filter one drop of each mixed fuel sample diluted in the indicated manner so that they do not come into contact. After the appearance of spots on the filter, their appearance is visually evaluated. If in the center of each of these spots there is no noticeable darker spot of smaller diameter, they mix other portions of the analyzed fuel with mixtures of toluene and n-heptane, in which the toluene concentration is below 40%, namely 30, 20 and 10 vol.%, And after similar operations evaluate the appearance of spots. If a darker spot of a smaller diameter is detected inside the resulting spot, with a toluene concentration of, for example, 10 vol.%, And its absence with a toluene concentration of 20 vol.% With n-heptane, dilution of fuel portions (2 g each) is carried out with mixtures according to (10 cm ³ ) toluene and n-heptane with toluene concentrations in them of 12, 14, 16 and 18 vol.%, i.e. in the range of toluene concentration in n-heptane from 10 to 20 vol.%. If, for example, a darker spot inside the drop spot is detected at 16 vol.% Toluene concentration in a mixture with n-heptane and not detected at 18 vol.% Toluene mixed with n-heptane, then consider that toluene equivalent the analyzed fuel is 17 units, i.e. corresponds to the average concentration of toluene in a mixture with n-heptane, at which a portion of the analyzed fuel in a mixture with toluene and n-heptane with a toluene concentration of 16 vol.% indicates the presence of a darker spot inside the entire drop spot, but at 18% it does not.

If inside the spot from a drop obtained from diluting a portion of the fuel with a mixture with a concentration of toluene in n-heptane of 60 vol.% (I.e., in the first of all the cases cited) a darker spot is detected, then solutions of portions of fuel with mixtures are prepared, in which the toluene fraction in n-heptane increases and amounts to 70, 80 and 90 vol.%. Moreover, if, for example, a darker spot is found in the spot from a drop of a portion of fuel dissolved in a mixture with 80 vol.% toluene in n-heptane (if absent in a portion of fuel diluted with a mixture of 90 vol.% toluene in n-heptane), further search toluene fuel equivalent produce this range using the fuel portions of dilute mixtures with 82, 84, 86 and 88 vol.% toluene in n-heptane. The value of the toluene equivalent is determined as in the above first case. For example, if there is an internal spot in a mixture of toluene and n-heptane containing 86 vol.% Toluene, but not in a mixture with 88 vol.% Toluene, then the toluene equivalent is 87 units.

The value of the toluene equivalent is ≤30 units. is a criterion of straightforwardness (lack of secondary residual products of oil refining) in mixed fuels.

There is also a method for determining the secondary residual products of oil refining in mixed fuel when it is mixed with solutions consisting of xylene and n-heptane of various concentrations (GOST R 50837.4-95 residual fuels. Determination of straightness. Method for determining xylene equivalent).

When testing by this method, individual portions (2 g each) of the analyzed fuel are dissolved in 10 cm ^{3 of a} solution (one solution for each portion of fuel) consisting of xylene and n-heptane, in which the xylene volume fraction is initially 0, 45, respectively and 90% vol.%, xylene. From each resulting mixture of fuel and a solution of xylene with n-heptane, several non-contacting drops are applied to a paper filter with a medical pipette, dried and a solution with a maximum xylene concentration is revealed, which gives a darker ring inside the stain from the dried drop. The test is repeated using other solutions of xylene in n-heptane (in which the concentration of xylene in n-heptane changes by 5 vol.%) Until two samples with a concentration of xylene in n-heptane differing by 5 vol.% Show : one (with a higher concentration of xylene) is the absence of a darker spot inside the spot from the drop, and the other (with a lower concentration of xylene) is its presence. The final spot analysis is carried out after 24 hours. The xylene equivalent is written in a fraction, in the numerator of which the minimum concentration of xylene in a mixture with n-heptane, in which a darker ring is present inside the common spot, but is absent in the denominator.

A xylene equivalent value of less than or equal to 25/30 is a criterion of straightforwardness (i.e., the absence of secondary residual products of oil refining in the investigated mixed fuel).

A common disadvantage of both methods is the low accuracy due to the subjectivity of the visual assessment of the presence of a darker spot inside the entire (also darkened) spot from a drop of a diluted portion of the fuel with a mixture of toluene or xylene with n-heptane.

Closest to the claimed method, taken as a prototype, is a method for determining straightness (lack of secondary residual products of oil refining) in mixed fuels by the indicator "spot number" (GOST R.50837.7-95. Residual fuels. Determination of straightness. Method for determining stability and compatibility on the spot).

This method (sections 7 and 9 of GOST R 50837.7-95) involves the selection of a fuel sample in an amount of at least 500 cm ³ , its preparation (mixing and, if necessary, heating it to a liquid state), mixing the sample with a distillate component in the ratio of 1 : 1, heating the mixture (1 drop applied to a special chromatographic paper of foreign manufacture) to 100 ° C, estimating the precipitate formed (by the appearance of a spot from a drop dried at 100 ° C) for 1 hour. By the type of spot on chromatographic paper (namely, by the diameter of a darker color in the center of the spot compared to the rest of the less darkened spot), it (according to the description of standard spots) is assigned a number (from No. 1 to No. 5). When assigning a spot number to a number less than or equal to No. 3, the fuel is considered straight-run (i.e. not containing secondary residual products of oil refining) - note to section 9 of GOST R 50837.7-95.

The disadvantage of this method is the relatively low accuracy and reliability of determining the secondary residual products of oil refining in mixed fuels, associated with the subjectivity of the visual assessment of the type of spots and the need to use foreign materials.

The technical result of the invention is to increase the accuracy and reliability of determination, the possibility of differentiating mixed fuels according to the content of quality assurance and / or AHB with the simultaneous use of only domestic materials.

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, heating the mixture to a temperature of 100 ° C and estimating the precipitate released, according to the invention, mixing the sample with distillate component is carried out until the viscosity of the mixture at 100 ° C equal to (1,75 ± 0,05) mm ² / s, the required amount of the mixture is poured into a pre-weighed metal cell ₁ m, fix cell weight with a mixture of m _2, after heating the mixture to 100 ° C is maintained cuvette with the mixture for 50 minutes in an oven at a temperature of (105 ± 3) ° C, centrifuged the mixture at a temperature sufficient to maintain a melt paraffin in liquid form, the liquid part is drained, the residue remaining in the cuvette is mixed with petroleum ether, after which the resulting solution is centrifuged, the liquid part is drained, the residue remaining in the cuvette is dried to a constant mass, which is fixed m ₃ , then asphaltenes are separated from this precipitate, for whereupon the precipitate is mixed with toluene, centrifuged, the liquid toluene part is drained, the residue remaining in the cuvette is brought by drying to a constant mass, which is fixed by m ₄ , after which the information indicator is calculated according to the following dependence:

A - information indicator (% wt.);

m ₁ is the mass of the empty cell, g;

m ₂ - the mass of the cell with diluted to a viscosity (1.75 ± 0.05) mm ² / s at 100 ° C mixture, g;

m ₃ is the mass of the cell with the precipitate after washing with petroleum ether and drying, g;

m ₄ - the mass of the cell with the precipitate after washing with toluene and drying, g,

and with a value of A ≤0.005% by weight, the absence of secondary residual products of oil refining in the analyzed fuel is judged.

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 a specified viscosity (1.75: 1: 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 in them;

- 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 guarantee the melting of the highest melting hard paraffins present in any mixed fuel and their long-term storage in the molten form. (B.V. 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 (40 minutes as an option) ensures the precipitation from the mixture at its low viscosity (l, 75 ± 0.05) mm ² / s at 100 ° С (in comparison with commercial 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 after centrifugation to isolate the precipitate (as an option (3000 = 1 = 100) min ^-1 for 10 minutes ;

- 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 oven, a stable precipitate can be obtained (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 )

During the research, the authors obtained a mathematical dependence that allows to determine the value of the information indicator “A” and its numerical (threshold) value, indicating the absence of secondary residual products of oil refining in mixed fuel, which is: A≤0.005% wt.

The essence of the claimed method lies in the fact that mixed fuels containing OTK and OVB, in contrast to fuels containing only primary (straight-run) oil refining residues (fuel oil, tar), contain a significantly larger number of asphaltenes. In turn, asphaltenes have a density of up to 1100 kg / m ³ , which is higher 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 operating parameters and the necessary sequence of methods of the claimed method, mixed fuel samples were prepared (table 1), covering their entire range (in viscosity), one of which (sample No. 1 - fuel oil F5 according to GOST 10585) contains only primary (straight-run) oil refining products, and the rest (samples 2-9) - and secondary residual oil refining products.

The method is implemented as follows.

Example 1

A sample of mixed fuel (sample 1) with a viscosity at 100 ° C of 7.8 mm ² / s 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 1 having a viscosity of 100 ° C 1.76 mm ² / s. 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 tile to 100 ° C, place it in a drying oven, preheated 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-weighing techniques). ) to a constant mass 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 is drained from the cuvette, the cuvette with the precipitate is placed in the oven, preheated to 140 ° C for 30 minutes, after which the cuvette with the precipitate is taken out of the oven, cooled to room temperature, weighed and the cuvette with sediment (indicated the reception E-drying-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 1 was:

The resulting value of 0.0036% wt. information indicator “A” is less than the value indicating the presence of secondary residual products of oil refining in mixed fuel (ie, value A≥0.005% wt.), which confirms the absence of secondary residual products of oil refining in this mixed fuel sample.

Example 2

A sample of sample No. 6 is taken in an amount of 47.8 g, in which 2% of the secondary residual product of the OVB oil refining is present, and 240.2 g of diesel fuel is added to it, obtaining 288 g of a mixture with a viscosity of 1.78 mm ² / s at 100 ° C, which satisfies the requirement of the claimed method.

In a pre-weighed metal cuvette m ₁ , which is fixed (m ₁ = 62.5215 g), the required amount of the mixture is added. The mass of the cell with a mixture of m _{2 is} fixed, m ₂ = 132.5215 g.

Heat the cuvette with the mixture on the tile to 100 ° C and place it in a drying oven preheated to a temperature of (105 ± 3) ° C for 50 minutes.

After 50 minutes, remove the cuvette with the mixture, place it in the rotor of the TsLS-3 centrifuge, in the rotor chamber of which it is set in advance and subsequently maintained at a temperature of (60 ± 2) ° С, and the mixture is centrifuged for 40 minutes.

After 40 min of centrifugation, the liquid part of the mixture is discharged from the cuvette together with melted paraffin wax, 15 cm ^{3 of} petroleum ether is poured into the cuvette, it is mixed with the precipitate, centrifuged for 10 min at (3000 ± 100) min ^-1 , the liquid part is drained from the cuvette (petroleum ether with the remains of the mixture).

The cuvette with the remaining sediment is installed in an oven heated to 100 ° C. After 30 minutes, remove it from the oven, cool to room temperature, weigh it, and bring the cuvette with sediment to a constant mass, which is fixed, by additional drying, m ₃ = 62.5320 g.

Pour the cuvette with the remaining precipitate 15 cm ^{3 of} toluene, mix it with the precipitate and centrifuged for 10 min at (3000 ± 100) min ^-1 . The toluene solution is poured with the asphaltenes dissolved in it, and the cuvette with the precipitate is placed in an oven heated to 140 ° C for 30 minutes. A cuvette with a precipitate is taken out, cooled to room temperature, weighed, the cuvette with a precipitate is brought to a constant mass, which is fixed, by additional drying at the same temperature, m ₄ = 62.5259 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 6 was:

The resulting value of 0.0087% wt. information indicator “A” is greater than the value indicating the absence of secondary residual products of oil refining in mixed fuels (A≤0.005% wt.), which confirms the presence of 6 secondary residual products of oil refining in the sample (2% wt.

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 when their content in the original analyzed mixed fuel in an amount of not less than 2.0% wt. (test results for samples 2, 3, 4, 5, 6, 9), and the information indicator “A” itself varies over a wide range (from 0.0074 to 1.9400), i.e. more than two orders of magnitude, for samples with a content of TCI or AEC of at least 2% wt.

This makes it possible to differentiate well mixed fuels according to the information indicator “A” regarding the content of OTK and OVB in them.

The claimed method tested a number of samples of commercial mixed fuels, according to which the results of tests of the prototype are known. The test results of these fuels, in particular naval fuel oil F5 according to GOST 10585, high-viscosity marine heavy (SVT), superheavy (SVS) according to TU 38.101314-90, the so-called "intermediate" ship fuels IFO-180 according to TU 0252-014-00044434-2001 , as well as composite marine fuels according to TU 38.401-58-302-2001 (RMN-35) are given in table 3.

From the data given in table 3 it follows that by the prototype method all tested samples of mixed marketable fuels are straight run (since the “spot number” indicator is less than 3 (column 5) and is 1-2), i.e. not containing residual products of secondary oil refining (OTC and OVB). However, from the same table 3 it follows that in samples 5, 6, 8, 9, 11 (rows 5, 6, 8, 9, 11, column 4, respectively), these products are contained in an amount of up to 75% wt., Which indicates unsatisfactory accuracy of the prototype. The low accuracy of the prototype is also evidenced by the fact that samples 1 and 2 (rows 1 and 2, column 5), obviously (according to the technology for the production of fuel oil F5 according to GOST 10585) that do not contain OTC and OVB (column 4) have the same spot number ( No. 2), as samples 5, 6, 8, and 11 (respectively lines 5, 6, 8, and 11, column 5) knowingly containing (up to 75% wt.) OTC and OVB (sample 6, line 6, column 4 ) Sample 9 (row 9), known (column 4) containing OTC (OVB), has a smaller spot number (No. 1) (column 5) than samples 1 and 2 (rows 1 and 2, column 5), which obviously do not contain secondary products oil refining, which contradicts their composition and also indicates a low accuracy of the prototype.

In accordance with the description of the spots, an increase in their numbers means an increase in the quantity of secondary residual products of oil refining in mixed fuels, which is simultaneously associated with a deterioration in their stability (an increase in the tendency to precipitate) (T.N. Mitusova, I.A. Pugach, N.P. .Averina. Chemistry and technology of fuels and oils, No. 2, 2001, p.6-7). For fuel samples No. 5, 6, 8 by the number of spots this is not observed, since for all of them the spot has No. 2. The specified low accuracy of the prototype is associated with the subjectivity of the visual assessment of the type of spots.

According to the claimed method, the samples in which there is no OTC and OVB include residues contained only in samples 1-4 and 10 (rows 1-4 and 10, column 13), since the indicator "A" (column 13) for them does not exceed 0.005% wt. In all other samples (Nos. 5–9 and 11 — lines 5–9 and 11, column 13, respectively), the “A” indicator exceeds 0.005% wt. and ranges from 0.0576 (sample 7, line 7, column 13) to 1.4154% by weight (sample 6, line 6, column 13). This confirms (in contrast to the prototype) the reliability of the claimed method.

Based on the data given in tables 1, 2, 3, we can tentatively judge the amount of secondary residual products of oil refining in mixed fuels.

So, when: 0.0074 <A <0.1928, it is from 2 to 10% wt .;

0.1928 <A <0.4569 it is from 10 to 20% wt .;

0.4569 <A <1.1509 it is from 20 to 50% wt .;

1,15 09 <A <1,9400 it is from 50 to 80% wt .;

The data given in table 3 for commodity mixed fuels (column 13) (samples 5, 6 and 8), according to which the quantity of OTC or AEC contained in it is known, fit into the above limits and confirm the conclusion about the reliability of the proposed method. With this in mind, and for samples containing OTC or OVB, but the number of which is not given, we can expect that this amount is respectively from 2 to 10% wt. (for samples 7 and 9 rows 7 and 9, column 13) and from 50 to 80 (for sample 11 row 14 column 13) %% wt.

Knowing the value of indicator “A” allows you to select the optimal fuel samples for ships with different complexity of fuel systems.

Thus, the invention has significant advantages over the prototype. If necessary, in special circumstances (when naval ships are far from their bases), it is possible to select from those available on-site mixed fuels those that do not contain residual products of oil refining and prepare them (by adding diesel fuel with a flash point of more 60 ° C) low viscosity naval fuel oil F5, i.e. black oil, which is the only one approved for use on Navy ships.

The identification among commercial mixed fuels of those that do not contain OTC and OVB allows them to be given preference to business entities during the operation of ships, as well as, if necessary, laying them down for longer than usual storage periods (in reserve )

The application of the invention will allow due to the combination of the claimed techniques to achieve:

- increase the reliability of test results;

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

- the possibility of differentiating mixed fuels by their content of secondary residual products of oil refining;

- use when testing only domestic materials.

Table 1
The composition of the samples of mixed fuels for testing according to the claimed method Type of components Samples of mixed fuels,% wt. one 2 3 four 5 6 7 8 9 fuel oil F-5 Primary (straight run) residual products oil refining: - tar - - - - 77 77 79 79 17 - fuel oil 75 90 80 fifty - - - - - Secondary (indirect) residual products processing: - the remainder of thermocracking (OTC - - - - 2 - one - - - Visbreaking balance (OVB) - 10 twenty fifty - 2 - one 80 Distillate product (diesel fuel for marine diesel engines according to GOST 305) 25 - - - 21 21 twenty twenty 3

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, heating the mixture to a temperature of 100 ° C and estimating the precipitate generated, characterized in that the mixture is mixed with a distillate component until the viscosity of the mixture is reached at 100 ° C of (1,75 ± 0,05) mm ² / s, the required amount of the mixture is poured into a preweighed ₁ m metal cell fixed cell weight with a mixture of ₂ m after heating the mixture to 100 ° C is kept to After mixing for 50 min in an oven at a temperature of (105 ± 3) ° С, centrifuged this mixture at a temperature sufficient to preserve molten paraffins in liquid form, drained the liquid part, the residue remaining in the cuvette was mixed with petroleum ether, after which the resulting solution is centrifuged, the liquid part is drained, the residue remaining in the cuvette is brought to a constant mass by drying, which is fixed m ₃ , then asphaltenes are separated from this precipitate, for which the precipitate is mixed with toluene, centrifuged, the liquid drained the toluene portion, the residue remaining in the cuvette is brought by drying to a constant mass, which is fixed by m ₄ , after which the information indicator is calculated according to the following dependence:

where A is an information indicator, wt.%;
m ₁ is the mass of the empty cell, g;
m ₂ - the mass of the cell with diluted to a viscosity (1.75 ± 0.05) mm ² / s at 100 ° C mixture, g;
m ₃ is the mass of the cell with the precipitate after washing with petroleum ether and drying, g;
m ₄ is the mass of the cell with the precipitate after washing with toluene and drying, g;
and when the value of A ≤0.005 wt.% judge the absence of secondary residual products of oil refining in the analyzed fuel.