RU2604843C2 - Method for sampling oil and oil products films from water surface and device for implementation thereof - Google Patents

Abstract

FIELD: oil and gas industry; measurement technology.

SUBSTANCE: invention relates to analytical research of films from oil and oil products and can be used for determining composition of oil and oil products in natural water reservoirs. Device is made in the form of hollow cylinder 1 with plug 6 from inert material and tip 4, in which there is precision valve 3. Sampler has a developed inner surface with inner section diameter and height ratio of 1:3-1:10. On the outer surface of the sampler there are marks 2 for measuring volume of the collected sample. Before sampling the sampler is annealed at temperature of 500-1,000 °C for 5-20 minutes. Then it is cooled to ambient temperature and lowered into the analyzed medium. Fixed sample volume is sampled. Then water phase is drained slowly with speed of water surface movement inside the sampler of 10-300 mm/min and the film is deposited on the inner surface of the specific area of the sampler, is analyzed for content of organic substance.

EFFECT: higher accuracy of analysis, possibility of performing quantitative analysis of organic substances in the taken sample, as well as possibility of sampling in field conditions.

10 cl, 7 dwg

Description

The invention relates to the field of analytical studies of films of oil and oil products, in particular to methods of sampling for subsequent analyzes.

A known sampler for assessing the thickness of the oil layer above water (RF Patent for the invention No. 2534791, publ. 10.12.2014. IPC G01N 1/10. G01F 23/04) [1] containing a thin-walled transparent vertical casing of a material that is not wetted by oil and petroleum products. The housing is made without a bottom and has a constant height internal area and a sharp edge in the lower part. In the upper part, the body is conically narrowed and connected to a flexible-shaped outlet, to which two valves are connected: a side valve for air passage and a central one for liquid passage.

This design of the sampler does not allow analysis of the selected film with high accuracy. The lack of accuracy of the analysis is due to the fact that the body of the sampler is made of non-wettable material, which does not allow for slow drainage of the sample and, as a consequence, the deposition of oil film on the surface of the sampler in sufficient quantities. The specified disadvantage is eliminated in the claimed solution.

A sampler is also known for evaluating the thickness of the oil layer above water (RF Patent for the invention No. 2452933, published December 10, 2014. IPC G01N 1/10. G01F 23/04) [2] containing a thin-walled vertical housing with a handle in the upper part and a conical saddle the valve in the lower part, and also a ball for overlapping a saddle. The ball is suspended on a fishing line from the handle, providing two positions of the ball relative to the saddle. Moreover, at the lower point of attachment of the fishing line to the handle, the ball freely lies on the saddle and overlaps it, and at the upper point of attachment of the line the ball is raised above the saddle.

The disadvantage of this invention is also the low accuracy of the analysis of the selected sample. The low accuracy of the analysis is due to the fact that the design of the device does not provide for the deposition of film on the surface of the sampler. In the claimed decision, the specified drawback is eliminated.

As a prototype, the method and device closest in technical essence to the proposed solution were selected, described in the article “Determination of the concentration of oil products and oils in films on the surface of the water using a solid electrolyte analyzer” (B.K. Zuev, V.V. Kovalenko, E. V. Kulbachevskaya, A. Yu. Olenin, VV Yagov. Determination of the concentration of oil products and oils in films on the surface of the water using a solid electrolyte analyzer // Journal of Analytical Chemistry. - 2001. - T. 65. - No. 5. - C . 543-547) [3].

The method for selecting films of oil products from the surface of the water, described in article [3], is as follows. Samples of organic substances at the water-air interface are taken using a sampler (probe) immersed in water and then extracted from the water. During the extraction of the sampler (probe), the organic film is transferred from the surface of the water to the sampler (probe). Next, the probe is placed in a high-temperature reactor through which a binary mixture of oxygen-inert gas is pumped, after which a change in the oxygen content in the binary mixture is recorded using an oxygen sensor. The amount of organic matter transferred to the surface of the sampler is determined by the amount of oxygen expended in the oxidation of the sample in a high-temperature reactor.

The device for the selection of films of oil products and determination of the total content of organic substances on the water surface described in [3] consists of a sampler (probe), an argon source, a dosing solid electrolyte cell (TEM), a reactor with a measuring TEM, a sample transfer device, and cuvettes with water, control unit and registration, a stimulator of gas consumption. The sampler is a thin round plate with a diameter of several mm, made of platinum foil or fluoroplastic film.

The disadvantages of the method and device selected as a prototype include, first of all, the low accuracy of the analysis of the selected sample, due to the fact that it is impossible to accurately determine the surface area of the aqueous phase from which the sample is taken. The method and device of the prototype allow for a qualitative analysis of the oil film, however, the quantitative analysis is not possible. In addition, the complexity of sampling for analysis does not allow its use in the field.

The technical problem solved in the proposed solution (method and device) is to increase the accuracy of the analysis, the ability to conduct a quantitative analysis of organic substances in the selected sample, as well as the ability to take samples for analysis in the field.

This technical problem is solved due to the fact that in the known method, including immersion of the sampler in the test medium, the analysis of the film deposited on the surface of the sampler, before sampling, the sampler with an open valve is preliminarily annealed in a furnace at a temperature of 500-1000 ° C for 5- 20 minutes. Then the sampler is cooled to ambient temperature, after which it is immersed in the test medium and the risk immersion depth is monitored on the outside of the sampler, by adjusting the selected volume with the help of a precision valve. The volume of the sample taken is controlled by the risks of the scale printed on the outside of the sampler. Then, the aqueous phase is slowly discharged from the selected sample at a speed of movement of the water surface inside the sampler of 10-300 mm / min, while a film of organic matter settles on the inner surface of the sampler

For analysis, the film deposited on the sampler can be removed by stripping with a solvent, such as carbon tetrachloride.

Analysis of the film deposited on the inner surface of the sampler can also be carried out by the express method, for this the sampler is connected to a sensor that determines the oxygen content in the air, heated in a furnace in a stream of air passing through the internal volume of the sampler to a temperature of 500-1000 ° С . Using an oxygen sensor, the amount of oxygen needed to oxidize the substances that make up the film is determined. Then conduct a qualitative and quantitative analysis to determine the content of organic substances in the film.

The problem is also solved due to the fact that in the known device containing a sampler of inert material, said sampler is made in the form of a hollow cylinder with a developed inner surface with a ratio of the diameter of the internal section to height 1: 3-1: 10. On the one hand, the sampler can be closed with a stopper made of an inert material, and on the other hand it is made with a tip in which a precision valve is installed; risks are taken on the external surface of the sampler to measure the volume of the sample taken. The sampler may be made of quartz, glass or ceramic material.

Distinctive features of the proposed technical solution, the method of selecting films of oil and oil products from the water surface are as follows. The sampler is preliminarily annealed in an oven at a temperature of 500-1000 ° C and cooled to ambient temperature. With the valve open, the sampler is immersed in an aqueous medium, according to the risks from the outside of the sampler, the immersion depth of the sampler and the volume of the liquid sample inside the sampler are controlled and a fixed sample is taken. Then the aqueous phase is slowly drained from the sampler, while the speed of moving the boundary of the surface of the water inside the sampler is 10-300 mm / min. Next, an analysis of the film transferred to the inner surface of the sampler, on the content of organic substances.

Distinctive features of the proposed technical solution - a device for the selection of films of oil and oil products from the surface of the water is that the sampler is made in the form of a hollow cylinder with a developed inner surface with a ratio of the diameter of the internal section to height 1: 3-1: 10, has a cork of inert material with on the one hand and on the other hand a tip with the precision valve installed in it. On the outer surface of the sampler, risks were taken to measure the volume of the sample taken.

The essence of the invention is illustrated by drawings:

FIG. 1. The device of the sampler

FIG. 2. Annealing the sampler

FIG. 3. The position of the sampler before sampling

FIG. 4. Sample set

FIG. 5. Removing water from the sampler

FIG. 6. Film dissolution

FIG. 7. Determination of the content of organic substances in the film, where:

1 - Hollow cylinder;

2 - Risks to determine the volume of fluid;

3 - Precision valve;

4 - Tip;

5 - The open end of the tube;

6 - Cork;

7 - Annealing furnace;

8 - Water medium (phase);

9 - Film of oil or petroleum products;

10 - film solvent;

11 - Oxygen sensor;

12 - Gas flow inducer;

13 - Airflow.

The selection of films of oil and oil products from the surface of the water and analysis of the samples is carried out as follows.

Before use, the sampler 1 (Fig. 1) is preliminarily annealed in a furnace 7 (Fig. 2) in an air atmosphere at a temperature of 500-1000 ° С for 5-20 minutes. The temperature and annealing time are determined by the material of sampler 1. During annealing, extraneous organic matter is removed from the surface of sampler 1. In order to avoid dust ingress after annealing, the sampler 1 is closed with a stopper 6 (Fig. 1) of inert material and cooled to ambient temperature, for example, 18-28 ° С.

For sampling, the precision valve 3 is opened, the plug 6 is removed from the cylinder, and the sampler 1 is slowly lowered vertically into water (aqueous medium 8) (Fig. 3), on the surface of which oil or oil products are in the form of a film 9. The immersion depth of sampler 1 is controlled with using fig 2 (Fig. 4). Sampling takes place from the water surface of a known area, determined by the internal cross-section of sampler 1. When the sampler is immersed in an aqueous medium (Fig. 4), water, as well as oil or oil products in the form of a film 9, enter the interior of the sampler 1. The required sample volume is taken, adjusting it with the help of valve 3 for risks 2 on the outer surface of the sampler 1.

To precipitate the organic film in sampler 1, the valve 3 is closed on its inner surface and slowly begin to take the sampler out of the water so that the water level in the sampler is higher than the level of the water surface from which the sample is taken (Fig. 5). In this case, the open end of the sampler 5 can remain immersed in the aqueous phase 8. The speed of movement of the upper boundary of the water inside the sampler can vary from 10 to 300 mm / min and depends on the thickness of the detected film on the surface of the water. As the water level in the sampler 1 decreases, a film from the selected sample is deposited on its inner surface. After draining the entire volume of the aqueous phase from the sampler, an analysis of the film 9 is carried out, deposited on the inner surface of the sampler 1.

Two analysis options are possible:

1. - With desorption of the film with a solvent, followed by a qualitative and quantitative analysis of the content of organic matter in the film.

2. - Direct analysis of the total content of organic substances in the film directly in the sampler 1.

1. Film desorption. With the valve 3 closed, through the open end 5, a known volume of solvent 10, for example carbon tetrachloride, is poured into the sampler 1 to remove the film from the surface of the sampler, then close the end 5 with a stopper 6 and shake the sampler. In this case, organic substances located on the inner surface of the sampler 1, pass into the solution (Fig. 6). After that, the organic matter content of the film is determined using analytical methods, for example, IR spectroscopy, chromatography or oxythermography.

2. Direct analysis of the total content of organic substances in the film. For express analysis (Fig. 7), a sampler 1 with a film adsorbed on the inner surface is connected to an oxygen sensor 11 and to a gas flow inducer 12, then the sampler is placed in a high-temperature furnace 7 with the possibility of heating to 500-1000 ° С, a gas stream is pumped ( for example, air) 13 containing oxygen, through the internal volume of the sampler, simultaneously record the change in the oxygen content in the gas stream 13. The amount of oxygen spent on oxidation is a value similar to the chemical oxygen consumption (COD). The value of COD is widely used to determine the total content of organic substances in water. In this case, to characterize the organic film on the surface of the water, you can use the COD value divided by the internal cross-sectional area of the sampler (in mg · O / cm ² ).

The proposed method for taking oil and oil products from the water surface and a device for its implementation can improve the accuracy of the analysis of the selected sample for the content of organic substances due to the fact that the surface area from which the sample is taken is precisely known, this area corresponds to the internal cross-sectional area of the sampler. In addition, the accuracy of the analysis increases the preliminary annealing of the sampler, since annealing removes organic matter from the surface of the sampler. Since the proposed device is quite simple and oversized, it can be used for sampling in natural reservoirs with subsequent qualitative and quantitative analysis in laboratory conditions. This expands the scope of its application. The implementation of the sampler with a developed inner surface contributes to a more efficient sedimentation of the organic film by increasing the surface area for deposition of the film, which also increases the accuracy of the analysis.

Bibliography

1. RF patent for the invention No. 2534791, publ. 12/10/2014. IPC G01N 1/10. G01F 23/04.

2. RF patent for the invention No. 2452933, publ. 12/10/2014. IPC G01N 1/10. G01F 23/04.

3. B.K. Zuev, V.V. Kovalenko, E.V. Kulbachevskaya, A.Yu. Olenin, V.V. I'm ready. Determination of the concentration of petroleum products and oils in films on the surface of the water using a solid electrolyte analyzer // Journal of Analytical Chemistry. - 2001. - T. 65. - No. 5. - S. 543-547.

Claims (10)

1. A method for selecting films of oil and oil products from the surface of the water, comprising immersing the sampler for selection in the test medium, removing it from the medium, analyzing the film deposited on the surface of the sampler, characterized in that the sampler is preliminarily annealed in an oven, then cooled to ambient temperature , after immersion, control the immersion depth, use a precision valve to control the sample volume, after taking a fixed sample volume, the aqueous phase is slowly drained from the sample, then analysis carried films deposited on the inner surface of the probe on its content of organic substances. 2. The method according to p. 1, characterized in that the sampler is preliminarily annealed in a furnace at a temperature of 500-1000 ° C. 3. The method according to p. 1, characterized in that the sampler is preliminarily annealed in a furnace for 5-20 minutes. 4. The method according to p. 1, characterized in that the aqueous phase from the selected sample is drained at a speed of movement of the surface of the water inside the sampler 10-300 mm / min. 5. The method according to p. 1, characterized in that for analysis the film deposited on the sampler is isolated by desorption with a solvent, then the content of organic substances in the film is determined using analytical methods. 6. The method according to p. 1, characterized in that the analysis of the film deposited on the inner surface of the sampler can be carried out by the express method, for this the sampler is connected to an oxygen content sensor, heated in an oven in an air stream to a temperature of 500-1000 ° C determine the amount of oxygen necessary for the oxidation of the film, then determine the content of organic substances in the film. 7. The method according to p. 5, characterized in that carbon tetrachloride can be used as a solvent. 8. A device for selecting films of oil and oil products from the surface of the water, containing a sampler of inert material, characterized in that the sampler is made in the form of a hollow cylinder with a developed inner surface, which on the one hand can be closed with a stopper of inert material, and on the other hand made with a tip in which a precision valve is installed; on the outer surface of the sampler, risks are taken for measuring the volume of the sample taken. 9. The device according to p. 8, characterized in that the hollow cylinder is made with a ratio of the diameter of the inner section to the height of 1: 3-1: 10. 10. The device according to p. 8, characterized in that the sampler can be made of quartz, glass or ceramic materials.

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