RU178122U1 - ELECTROCHEMICAL CORROSION PROTECTION DEVICE FOR OIL AND GAS EQUIPMENT - Google Patents

Abstract

The utility model relates to devices for protection against electrochemical corrosion by exposure to a water-containing aggressive environment by an electric field. It is applicable in the oil and gas sector, in particular in oil refining and transportation of oil and oil products. The technical result of the utility model is the absence of energy costs to overcome the hydrodynamic resistance, since no electrodes are introduced into the oil or oil products stream, increasing the area of electrophysical impact, since the electric the field has lower losses in comparison with a constant electric field, as well as a decrease in the corrosion rate due to an increase in the value of hydrogen of medium pH and to reduce the oxidation-reduction potential (ORP).

Description

The utility model relates to devices for protection against electrochemical corrosion by exposure to a water-containing aggressive environment by an electric field. It is applicable in the oil and gas sector, in particular in oil refining and transportation of oil and oil products.

A device is known (RF patent 2339868, published November 27, 2008), containing a direct current source using a "sacrificial" electrode - a metal with low electrochemical activity with respect to iron, for example magnesium. A “sacrificial” electrode is installed in a housing made of a hollow cylinder equipped with flanges at both ends and placed on dielectric centralizers with holes. The device is located in the lowest possible part of the pipeline. A positive effect in the proposed device is ensured, firstly, by increased current density, due to the use of pumped liquid (water emulsified in oil) as an electrolyte, and, secondly, the effect of “cathodic passivity” since the inner and outer surfaces of the pipeline are coated with a strong Fe3O4 film (magnetite), additionally providing immunity from corrosion and elimination of defective areas along the pipeline.

The disadvantages of this device include the need for periodic replacement of the "sacrificial" electrode, for which it is necessary inside the tank or pipeline. In addition, the operation of this device creates additional hydrodynamic resistance to a moving oil product, which leads to the need for pipelines with a large cross section.

A known method of neutralizing static electricity in a substance stream (RF patent 2351100, published 03/27/2009) and a device for reducing the corrosion rate of an oil pipeline by removing electrostatic charge (RF patent 2490835, published 08/20/2013), in which electrodes for removing charges static electricity located in the flow of matter. This creates hydrodynamic resistance and additional turbulization of the flow of matter, which contributes to its electrification.

A known method of protecting underground metal multi-pipe pipelines from electrochemical corrosion and a device for its implementation (RF patent 2204626, published 05/20/2003). The invention comprises three single-phase DC voltage sources, input power rails, plus and minus output load rails, plus and minus rails of measuring circuits, connected in a certain way.

The disadvantage of these methods is a significant complication of the design of the equipment, which inevitably leads to a decrease in its reliability and an increase in energy consumption.

The closest is a method of controlling physicochemical processes in a substance and at the phase boundary (RF Patent No. 2479005, published April 10, 2013), where liquid media are selected as the object of influence, the effect on which is carried out at the phase boundary using electric non-linearly distorted signal with two intervals of uniformity, which ensures equipment performance, reduces the energy intensity of production, achieving optimal performance indicators of the process.

The present invention claims the use of a non-linearly distorted signal with two intervals of uniformity as a frequency-modulated signal regardless of the parameters of the DEL (wall layer of the oil product — metal structure) at the “liquid-solid” interface, which limits its effectiveness.

The objective of the claimed utility model is to increase the reliability of production equipment of the oil and gas sector and reduce the risk of emergencies during transportation, storage and processing of oil and oil products.

This problem is solved by changing the hydrogen pH of the water oil present, as well as changing the dissolution rate of iron due to electrophysical effects in the substance and at the interface.

To achieve a result, an alternating frequency-modulated potential (PCF) is supplied to the object of protection using an electric device (Fig. 1), which acts on a double electric layer (DEL) formed at the interface “liquid (water-containing corrosive medium) - solid substance (metal construction of the object of protection). ” From a device consisting of a high-voltage unit 1, an isolation transformer 2; the control unit for the modulation frequency ПЧМЧ 3 and the control and indication unit 4, ППММП is fed to the object of protection 5. Moreover, the electrode is mounted on the outside of the object of protection. Thus, the hydrodynamic resistance of the moving fluid inside the protection object is not created.

As a result of exposure to PCF, an alternating electric field of a given frequency is formed on the internal and external surfaces of the object of protection and the dielectric constant of the DEL is changed due to the alternating polarization of the substance at the phase boundary (Fig. 2), an increase in the pH value of the pH and a decrease in the redox potential (ORP), which leads to a decrease in the rate of corrosion of the metal. Without exposure to PCF, the dipoles of the DES are in a static state (Fig. 2a). Under the influence of the MFMP there is a constant reorientation of the dipoles of the DES in accordance with the direction of the lines of force of the alternating electric field (Fig. 2b).

In FIG. 1 shows a schematic diagram of the device and its connection to the object of protection.

In FIG. Figure 2 shows the polarization of DES: a) - without exposure to an external electric field; b) - with the electrophysical effects of PCMP.

The technical result of the utility model consists in the absence of energy costs to overcome the hydrodynamic resistance, since no electrodes are introduced into the oil or oil products flow, an increase in the zone of electrophysical impact, since the alternating electric field has lower losses in comparison with a constant electric field, as well as a decrease in the corrosion rate due to an increase in the pH value of the pH and a decrease in the redox potential (ORP).

The proposed method allows you to quickly change the parameters of the impact on the DES due to the modulation unit with adjustable signal parameters.

Utility Model Implementation

During laboratory tests of the utility model, its effect on distilled water was measured with pH and ORP measurements (Table 1), which was then used in studies of the macrophase of growth of living systems [1].

An increase in pH of 5.44% was achieved, and a decrease in AFP of 34%.

The results of experiments on the impact of PMPP on the corrosion rate of metals in various environments [2] are presented in table 2.

Thus, the industrial applicability of the utility model is proved.

Literature:

1. Shvetsova O.V., Shkrabak B.C., Knyazev A.S., Rodionov G.G. Intensification of plant nutrition of zero macrophase of growth and development of carbon mineral compounds by chemical and electrophysical methods // Bulletin of the St. Petersburg State Technological Institute (Technical University). - 2015. - No. 28.- S. 73-82.

2. Ivakhnyuk G.K., Ivanov A.V., Garifulin P.P. The use of scanning probe microscopy for studying corrosion processes under the influence of variable frequency-modulated potential // Scientific-analytical journal "Bulletin of the St. Petersburg University of the State Fire Service of the Ministry of Emergencies of Russia. - 2014. - No. 3. S. 12-19.

Claims (1)

Device for protection against electrochemical corrosion by exposure to a water-containing aggressive environment by an electric field, consisting of a high-voltage unit, an isolation transformer, an modulating unit of variable frequency-modulated potential and a control and indication unit, characterized in that the electrode is attached from the outside of the object of protection and does not create hydrodynamic resistance moving fluid inside the object of protection, and a decrease in the corrosion rate is achieved by increasing the pH value of the pH and reduction of the redox potential.

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