RU2473882C1 - Method and device for determining low-temperature viscosity, filtration ability and impurity of oil products - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method is based on the measurement of filling time of certain volume with oil product supplied via the tube under negative pressure action. By gradual product cooling, temperature is determined, at which the working volume filling time becomes higher than limit one - temperature of pumping ability (for oils) or filtration ability (for fuels). When determining low-temperature viscosity and pumping ability, the device tube filling time is measured. When determining filtration ability of fuels, filter is installed in addition, and capacity filling time is measured. When determining the impurity degree, the filling time of the capacity with filter is compared to that without any filter.

EFFECT: reduction of the time for determining low-temperature viscosity, pumping ability, filtration ability of oil products, degree of their impurity with mechanical impurities and possibility of determination of those properties.

5 cl, 3 dwg

Description

The invention relates to the field of analysis of petroleum products. The method allows to determine the pumpability, filterability (fuels, lubricants) at low temperatures and the degree of contamination of petroleum products. It can be used for express analysis of fuel and lubricants in machines; for research purposes; for qualification tests in any areas. The method is carried out by pumping petroleum products under the vacuum created by the piston through a tube (with a filter installed in the case of determining filterability and contamination of fuels). The selection of oil product can be made directly from the crankcase of the engine or gearbox, the fuel tank of the car, various containers and tanks at low temperatures. In the laboratory, a chilled product is analyzed (using a refrigerator, coolant, etc.). When conducting laboratory studies, curves are plotted against the temperature of the time of arrival of the reference chilled oil product through the tube (when determining filterability, a sleeve with a metal mesh is installed on the tube and the time it takes to fill the tank’s working volume with fuel). The constructed curves are used when testing the analyzed oil product. To determine the contamination, the ratio of the time of filling the device’s tank with an oil product with a filter installed on the tube to the time of filling the tank without a filter is found and compared with the same indicator for an uncontaminated oil product. EFFECT: reduced time for determination of low temperature viscosity, pumpability, filterability of oil products, their degree of contamination with mechanical impurities (at positive temperatures) and the ability to determine these indicators both in laboratory conditions and directly in machines, equipment, tanks, etc.

The invention relates to the refining, petrochemical industry and can be used in other areas to determine low temperature viscosity, pumpability, filterability and contamination of petroleum products.

A known method for the visual determination of turbidity and the onset of crystallization (GOST 5066-91. Petroleum products. Methods for determining the temperature of turbidity and the onset of crystallization). The essence of the method is to cool the test fuel sample and visually record the turbidity or the beginning of crystallization of the fuel. However, this method has the following disadvantages: tests must be carried out in laboratory conditions, a long analysis time, the disposal of the sample is required.

A known method of determining the limiting temperature of filterability (GOST 22254-92. Diesel fuel. Method for determining the limiting temperature of filterability on a cold filter. State standard of the USSR). The essence of determining the limiting filterability temperature by this method is to constantly cool the test fuel with an interval of 1 ° C, and to drain it through a wire filtration mesh under constant vacuum. The determination is carried out to a temperature at which crystals of paraffin separated from the solution on the filter cause the flow to stop or slow to such an extent that the filling time of a 20 ml pipette exceeds 60 s or the fuel does not drain completely into the measuring vessel. Disadvantages of the method - preliminary sampling and its subsequent disposal are required.

A known method for determining the viscosity of an automatic capillary viscometer (GOST 7163-84. State standard of the USSR). The essence of the method is that the lubricant is squeezed out of the cylinder by a rod through a capillary under the action of a pre-compressed spring. The lowering speed of the stem depends on the characteristics of the spring and the viscosity of the lubricant. From the curve recorded on a rotating drum with a pencil connected to the rod, it is possible to calculate the viscosity and its dependence on shear rate. The disadvantages of the method include the bulkiness of the equipment, the need for preliminary sampling and its disposal.

A known method of determining the degree of contamination of the liquid according to GOST 17216-2001 "Industrial cleanliness. Classes of purity of liquids ”, based on counting the number of particles of different sizes in a certain volume of liquid sample. Its disadvantages are complexity, the need for sophisticated equipment to count the number of particles of different sizes and unsuitability for express analysis.

Also known is a method for determining the degree of oil pollution, described in GOST 10734-64 "Lubricating oils with additives. Method for determining the washing potential ”, in which a solution of oil in gasoline is passed through a paper filter, the degree of contamination of the oil is judged by the filtration time and the color of the filter. The disadvantages of the method is the consumption of excipients, the inability to reuse the selected oil sample.

The closest capillary viscometer of constant flow rate (SOD, methods ASTM D 1092, ANSI Z11.72 and FTSM 306, NFT 06-139) was selected as a prototype as the closest in technical essence and achieved effect. The essence of the operation of the SOD capillary viscometer is that the lubricant is forced through the piston at a constant speed through the capillary with a diameter of 0.45 ... 3.8 mm with a ratio of tube length to diameter 40: 1. From the experimental points, a curve is built of the dependence of viscosity on the strain rate — the viscosity-velocity characteristic of the lubricant. However, the SOD viscometer has drawbacks - cumbersomeness, complexity in operation, high error, and preliminary sampling and its disposal are also required.

The purpose of the invention is the reduction of test time and the creation of opportunities for determining low temperature viscosity, pumpability, filterability and contamination of petroleum products at the location of equipment and petroleum products at low temperatures.

The implementation of the method.

The device (see figure 1) consists of:

- capacity 1;

- rod with piston 2;

- springs 3;

- tubes 4 with a diameter of 1.5 mm, a length of 520 mm (for determining filterability - with a diameter of 3 mm, 400 mm long);

- thermostat 5;

- latch 6;

- filter 7 with a mesh with a diameter of 12 mm with cells: for determining the degree of contamination - no more than 15 microns, for determining filterability - not more than 55 microns.

The method is as follows.

1) Laboratory studies of low temperature viscosity and pumpability of the oil product.

The analyzed sample is gradually cooled in a thermostat at a speed of 0.2 ... 1 ° C per minute. Every 1 ... 2 ° C determine the low temperature viscosity according to the following algorithm.

The spring is compressed, the device’s tube (1.5 mm in diameter, 520 mm long) is lowered into a container with cooled oil, the spring is released, and the stopwatch is simultaneously turned on. A vacuum is created in the capacity of the device, the oil product begins to rise. In this case, the time of filling the tube and the appearance of oil in the device’s capacity is fixed and entered in the table.

According to the data obtained, a graph of the dependence of viscosity on temperature is built. An example of a graph is shown in figure 2. The temperature at which the filling time of the tube and the appearance of oil in the tank becomes more than 300 s is taken as the maximum pumpability temperature.

2) Determination of low temperature viscosity of the oil product.

The low temperature viscosity of the oil product can be determined both in the laboratory (with sample cooling) and in cold weather on the street at the location of the equipment.

The algorithm for determining low-temperature viscosity is the same as in a laboratory study, except that the viscosity is determined at the same temperature. The measurement result is compared with the data for a given temperature from a graph obtained in laboratory studies.

In addition, without preliminary tests directly at the location of the equipment, it is possible to give a conclusion about the possibility of its use of a lubricant at a given temperature. Based on the studies of oils Lukoil SAE 15W-40, Shell Helix SAE 10W-40, Shell Helix SAE 5W-30, Nissan SAE 5W-40, I-40 and P-40 it was found that if the filling time of the tube and the appearance of oil in the tank more than 300 s, the lubricant will go too long through the oil channels to the friction units, which can lead to increased wear of machine parts or its emergency stop. Therefore, if the time of appearance of the oil product in the tank is more than 300 s, the operation of the equipment is not recommended.

3) Laboratory studies of the filterability of fuels.

The analyzed sample is gradually cooled in a thermostat at a speed of 0.2 ... 1 ° C per minute. Every 1 ... 2 ° C determines the filterability according to the following algorithm.

The spring is compressed, the device’s tube (3 mm in diameter, 400 mm long, with a filter installed at the end with a mesh size of 55 μm) is lowered into a container with cooled oil, the spring is released, and the stopwatch is simultaneously turned on. A vacuum is created in the capacity of the device, the oil product begins to rise. In this case, the time of filling the device’s capacity with fuel up to the mark of 20 ml is fixed and entered in the table.

According to the data obtained, a graph of the dependence of the filling time on temperature is built. The temperature at which the crystals of paraffin separated from the solution onto the filter cause the flow to stop or slow down to such an extent that the arrival time of 20 ml of fuel exceeds 60 s or the fuel does not drain completely when the rod is removed is taken as the limiting filterability temperature.

4) Determination of fuel filterability.

Fuel filterability can be determined both in the laboratory (with sample cooling) and in cold weather on the street at the location of the equipment or fuel tank.

The algorithm for determining filterability is the same as in a laboratory study, except that filterability is determined at the same temperature. The measurement result is compared with the data for this temperature from a graph obtained in laboratory studies.

5) Determination of the degree of contamination of the oil product with mechanical impurities.

To determine the degree of contamination of the oil product with mechanical impurities, the ratio of the time of filling the device’s tank with oil product with a filter installed on the tube to the time of filling the tank without a filter is determined and compared with the same indicator for uncontaminated oil product. The higher the value obtained, the more particles settle on the filter, the higher the degree of contamination of the oil product with mechanical particles. If the resulting ratio is greater than 2.5, the oil is unsuitable for further use due to the high content of mechanical particles.

In the case of determining the contamination, a filter is used with a mesh size of not more than 15 μm (15 μm is the maximum particle size under normal wear of friction units). To ensure the possibility of determining the contamination of the oil in the crankcase and in other similar situations, the filter is installed in front of the tank (figure 3) so that the device tube can enter the hole for the oil dipstick.

If the contamination of low-viscosity products (diesel fuel, etc.) is determined, an insert 8 (Fig. 3) with a diameter of 0.5 mm is installed at the end of the tube to increase the measurement accuracy.

The filling time of the container without filter allows you to evaluate the viscosity of the product.

Enumeration of figures. Figure 1 shows a device for determining low temperature viscosity, pumpability, filterability and contamination. Figure 2 shows graphs of the dependence of the tube filling time on temperature for oils Lukoil SAE 15W-40, Shell Helix SAE 10W-40, Nissan SAE 5W-40. Figure 3 shows a device with an additional insert and with an alternative installation of the filter.

Examples of tests of petroleum products of the proposed device.

1. Laboratory studies of low temperature viscosity and pumpability of engine oil SAE 15W-40 "Lukoil - Super". According to the methodology, the viscosity of the oil was determined in the temperature range -29 ... -12 ° C. According to the data obtained, a graph was constructed (Fig. 2, the upper graph). The graph shows that at -29 ° C the filling time of the tube becomes more than 300 s, therefore, we take -29 ° C for the maximum pumping temperature. At lower temperatures, the use of equipment with this oil is not recommended.

2. SAE 15W-40 Lukoil Super oil (fresh - reference) and SAE 15W-40 engine oil from the crankcase with a mileage of 12,500 km. The diameter of the device’s tube is 1.5 mm, and the tube length is 520 mm. Oil temperature -25 ° C. An analysis of the pumpability of the tested similar oil from the crankcase was carried out in the parking lot at an ambient temperature of -25 ° C. The test results are shown in table 1.

Table 1 Oil pumpability measurement results SAE 15W-40. Name of oil product Pumpability determination temperature, ° С The time of the appearance of the oil in the tank, s On a MRV ASTM D 4684 viscometer, MPa · s SAE 15W-40 oil (standard) -25 262 32,400 SAE 15W-40 oil (analysis) -25 304 37250

Comparing the obtained data with the results of laboratory analysis of fresh Lukoil-Super oil (Fig.2), we can see that the low-temperature viscosity increased by 15%. The filling time of the device’s tube is more than 300 s, therefore, at a given temperature, operating the vehicle with this oil is not recommended.

3. SAE 5W-40 Nissan engine oil (fresh - reference) and similar oil tested from the crankcase with a mileage of 9440 km. The diameter of the device’s tube is 1.5 mm, the tube length is 520 mm, and the spring force is 10 kgf. Oil temperature -35 ° C. An analysis of the pumpability of the tested similar oil was carried out in the parking lot at an ambient temperature of -35 ° С. The test results are shown in table 2.

table 2 SAE 5W-40 Oil Pumpability Measurement Results Name of oil product Pumpability determination temperature, ° С The time of the appearance of the oil in the tank, s On a MRV ASTM D 4684 viscometer, MPa · s SAE 5W40 oil (standard) -35 151 18000 SAE 5W40 oil (analysis) -35 162 19550

In this case, the low temperature viscosity increased slightly and is within acceptable limits.

4. Diesel fuel TU 38.401-58-110-94, tube diameter 3 mm, mesh diameter 12 mm, cell diameter 42-43 microns, tube length 400 mm. Spring force 10 kgf. The temperature of diesel fuel is -30 ° C.

The filter - coupling with mesh - is installed on the end of the tube.

We carry out several measurements with constant cooling of the fuel. When the sample temperature reaches the appropriate value (they are guided by the cloud point or the filterability temperature stated in the fuel passport), compress the spring, lower the filter tube into the fuel and unclench the spring, while turning on the stopwatch. When the fuel fills the capacity of the device to the mark of 20 ml, the filling time is recorded. Measurements are repeated after each decrease in the sample temperature by 1 ° С until a temperature is reached at which the flow through the filter stops or the fuel level does not reach the mark of 20 ml for 60 s. The temperature of the onset of the last filtration is recorded as the limiting filterability temperature on a cold filter. As a result of the tests, it was possible to optimize the dimensions of the tubes and filter used in the device and to achieve convergence of the measurement results by the device and device in accordance with GOST 22254-92.

For the experiment was taken diesel fuel "winter" 3-0.2-35 according to GOST 305-82. The sample was slowly cooled in the refrigerator and the ultimate filterability of diesel fuel was measured by the proposed device with a cold filter, compared with the results obtained in accordance with GOST 22254-92 "Method for determining the maximum temperature of filterability on a cold filter." The measurement results are shown in table 3.

Table 3 The results of determining the filterability of diesel fuel. No. Extreme temperature of filterability, ° С. according to GOST 22254-92 by the proposed method one -thirty -thirty 2 -29 -29 3 -thirty -29

The obtained results of measuring the maximum filterability of fuel from the vehicle’s fuel tank in the parking lot at an ambient temperature of -30 ° C correlate with the measurement results according to GOST 22254-92. The tests of oil products for pumpability and filterability at low temperatures by the proposed method showed good convergence with the results of measurements carried out on laboratory equipment by known methods.

5. For hydraulic oil, the degree of contamination with mechanical impurities was determined. The diameter of the device’s tube is 1.5 mm, and the tube length is 520 mm. The experiment was carried out at room temperature (25 ° C).

They took clean oil, determined the time for filling the working volume of the device’s capacity. It amounted to 50 s. Then, a filter with a mesh size of 15 μm was installed in front of the container. Filling time increased to 61 s.

Conducted a similar experiment with contaminated oil. Filling time without filter - 53 s, with filter - 68 s.

Contamination factor for pure oil:

k = 61/50 = 1.22.

Contamination factor for contaminated oil:

k = 68/53 = 1.283

The pollution factor increased slightly, the degree of oil pollution is low.

Claims (6)

1. A device for determining low temperature viscosity, pumpability, degree of contamination with mechanical impurities and filterability of the oil in the crankcase, fuel tank, tank, etc., characterized in that it contains a tank into which, under the action of the vacuum created by the piston with the spring, the fluid enters through a tube on which a removable filter is installed when determining the filterability and contamination of the oil product, and when analyzing low-viscosity oil products, an insert with a smaller inner diameter is installed. 2. The method for determining the low-temperature viscosity and pumpability of petroleum products and other viscous liquids using the device according to claim 1, characterized in that to determine the low-temperature viscosity, a series of experiments is carried out previously with a gradual decrease in temperature, in which the filling time of the device’s tube with the test fluid under vacuum is measured created by the piston, build a graph of the dependence of viscosity on temperature, and with its help evaluate the low-temperature viscosity of the product directly at the place of analysis at ambient temperature, and the pumpability temperature is taken to be the temperature at which the filling time of the device tube becomes more than 300 s. 3. The method for determining the low-temperature viscosity and pumpability of oil products and other viscous liquids according to claim 2, characterized in that to increase the accuracy of determining the viscosity of low-viscosity products at the end of the tube, an insert with a smaller diameter is installed. 4. The method for determining the filterability of fuels and other liquids using the device according to claim 1, characterized in that to determine the filterability in advance, with a gradual decrease in temperature, a series of experiments is carried out in which the time it takes to fill the working volume of the device’s capacity with the studied liquid passing through the filter under the influence of the vacuum created by the piston, a graph of the dependence of the filling time on temperature is built, and with its help, the filterability of the product is evaluated directly at the site I analyze (from a fuel tank, tank, etc.) at ambient temperature, and the temperature at which the filling time of the device’s tank becomes more than 60 s is taken as the limiting filterability temperature. 5. A method for determining the degree of contamination of an oil product or other liquid (in a crankcase, a fuel tank of a tank, etc.) with mechanical impurities using the device according to claim 1, characterized in that at an arbitrary temperature, the ratio of the time of filling the device’s tank with the contaminated product with the installed on the tube with a filter by the time the container is filled without a filter (at the same temperature), they are compared with the same ratio for a pure product, and the degree of liquid contamination is estimated by the difference between these values Khanicheskimi impurities. 6. A method for determining the degree of contamination of an oil product or other liquid (in a crankcase, fuel tank, etc.) with mechanical impurities according to claim 5, characterized in that to increase the accuracy of determining the degree of contamination of low-viscosity products, an insert with a smaller diameter is installed .

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