RU2648198C1 - Method of control of corrosion processes - Google Patents

Abstract

FIELD: defectoscopy.

SUBSTANCE: invention relates to means for monitoring and diagnosing corrosive processes within process vehicles and pipelines. Method includes labeling, fluid sampling and indicator monitoring. Mark is applied to predetermined areas on the inner metal surface of the object under study. Mark is chosen according the following conditions: resistance to working fluid, lack of analogues in the working fluid, biological and chemical inactivity with respect to the working fluid and the surface on which the mark is applied, as well as resistance to barothermic effects. During the object usage as a result of corrosion process, the mark together with the metal particles or anticorrosive coating exfoliates from the object and leaves the fluid extraction zone. According to concentration of marks the presence, the interval in which corrosion occurred, and the intensity of the corrosion process are determined.

EFFECT: fluorescent substances, or radical-type indicators, or substances with high thermal neutron absorption, or radioactive isotopes, or colored substances, are chosen as a mark.

5 cl

Description

Technical field

The invention relates to means for monitoring and diagnosing corrosion processes inside technological devices and pipelines.

State of the art

Currently, 350 thousand km of field pipelines are operated in Russia. About 50-70 thousand failures occur annually on oil field pipelines. 90% of failures are due to corrosion damage.

Of the total number of accidents, 50-55% falls to the share of oil recovery systems and 30-35% to the share of reservoir pressure maintenance communications. 42% of pipes do not withstand five years of operation, and 17% even two years. The annual replacement of oil field networks consumes 7-8 thousand km of pipes or 400-500 thousand tons of steel. When depressurizing pipelines and process equipment, enormous damage is caused to the flora and fauna of the region where the companies operate.

Timely identification of the presence and location of corrosion in technological devices, pipelines and utilities during continuous operation can prevent many involuntary downtimes and emergencies, identify the most characteristic places of occurrence of defects, on which special attention should be paid during examinations.

At present, the main tool of the pipeline diagnostic inspection system is in-line diagnostics. To date, various methods are used to diagnose pipelines, based on various physical laws.

Pipeline diagnostics using video

The use of the most modern methods for analyzing the state of pipelines is always accompanied at the final stage by a visual examination of the fact of identifying defects and omissions during an automatic examination. The quality of pipelines has recently been checked using video diagnostics from inside the pipe, in-pipe diagnostics of pipelines is carried out by special robots that gradually move along the pipe channel to form a continuous image, thereby identifying defects requiring localization. This method is able to detect only gross violations of the continuity of pipelines, to identify leaks in areas located in the ground or in closed tunnels, as well as places for clogging and deposition of silt sediments.

Pipe crimping

As the oldest and most reliable method, with high accuracy and reliability, in combination with a low cost of conducting, the method of crimping pipes with high pressure is used. After the installation of the pipeline, a gas mixture, mainly inert gases or water vapor, is fed into it under high pressure. Exceeding the working pressure by about several times, then there are joints, welds and places of fastening of pipelines to boiler equipment. Due to the pressure difference inside and outside the pipe, the leak immediately becomes visible due to the flow of condensed vapor precipitating during a sharp drop in pressure.

Non-contact magnetometric examination

Integrated express method. It is a type of metal magnetic memory method. It is based on registration and analysis of the distribution of intrinsic scattering magnetic fields (SIR) of products in order to determine the concentration zones of stresses, defects, and heterogeneity of the metal structure.

VIC

The visual and measuring control is regulated by the Instructions for visual and measuring control (approved by the resolution of the Gosgortekhnadzor of the Russian Federation of June 11, 2003 N 92). For visual measuring control, special sets of devices are used.

Ultrasonic flaw detection

Ultrasonic flaw detection - the search for defects in the product material by the ultrasonic method, that is, by emission and acceptance of ultrasonic vibrations, and further analysis of their amplitude, time of arrival, shape, etc.

Ultrasonic Thickness Gauging

Ultrasonic inspection of the thickness gauge is carried out in order to assess the actual value of the wall thickness of structural elements by the method of single measurements in places inaccessible to measure the thickness with a mechanical measuring tool. Ultrasonic scanning of thickness measurement is carried out by an echo-pulse method.

Ultrasonic testing (ultrasound screening)

This method allows you to quickly determine where the problem place is on the pipe. The method of directional waves used in the control is completely different from the methods used in traditional ultrasonic testing methods.

Thermal control

Thermal imaging inspection is one of the leading directions in non-destructive thermal imaging monitoring of the state of structures and electrical equipment. Thermal imaging is an effective way to identify defects.

Eddy Current Test Method

The eddy current monitoring method is based on the analysis of the interaction of an external electromagnetic field with the electromagnetic field of eddy currents induced by an exciting coil in an electrically conductive monitoring object (OK) by this field.

Electrical control

Methods of surveying the state of the electrochemical effect of underground pipelines

Classification can be carried out on a technological basis - measurements by the methods of electrometric diagnostics of the MG itself are carried out directly above the pipeline.

In-tube shells

In-line pipe diagnostics is based on the use of autonomous flaw detectors (pistons, pigs) moving inside a controlled pipe under the pressure of the pumped product (oil, oil products, gas, etc.). The projectile is equipped with equipment (usually ultrasonic or magnetic).

Acoustic Emission (AE)

The AE method is based on the registration and analysis of acoustic waves arising in the process of plastic deformation and fracture (crack growth) of controlled objects. This allows you to create an adequate system of classification of defects and criteria for their assessment.

Radiation Control Methods

Radiation control methods are based on the registration and analysis of ionizing radiation during its interaction with the controlled product. The most commonly used methods are the control of transmitted radiation, based on various absorption of ionizing radiation.

Magnetic particle method

The magnetic particle method, among other methods of magnetic control, has found the greatest application, due to the ease and simplicity of obtaining the desired result.

Remote Controlled Diagnostic Complex (TDK)

TDK is a telecontrolled diagnostic complex for examining pipelines from the inside. TDK is designed to control pipelines with a diameter of 700-1400 mm. Moving inside the pipe, the robot measures the thickness of the walls, reveals defects in the pipe body and conducts visual inspection.

X-ray crawler

Crowler is an autonomous self-propelled X-ray complex designed to control the quality of welded pipe joints. This is a completely independent, exposed, wireless device.

Optical control

The optical range of the spectrum, as defined by the International Commission on Lighting (CIE), is composed of electromagnetic waves whose length is from 1 mm to 1 nm. Optical methods are based on the use of reflection phenomena.

Penetrating Substances

Capillary control is also used for objects made of ferromagnetic materials, if their magnetic properties, shape, type and location of defects do not allow achieving the required sensitivity by the magnetic particle method.

Technical endoscopy

An endoscope (or borescope) is an optical device that is used in visual inspection for various purposes. For example, an endoscope (borescope) is used in the technique for examining hard-to-reach spots.

Hardness test

Hardness testing is a method of non-destructive testing of the hardness of metals, alloys, rubber, plastic, concrete and other materials. Hardness testing is one of the main types of mechanical testing of metal and an effective means of diagnosing its structural-mechanical state.

Metal Magnetic Memory Method

The processes preceding operational damage are changes in the properties of the metal (corrosion, fatigue, creep) in stress concentration zones. Accordingly, the magnetization of the metal changes, reflecting the actual stress-strain state of pipelines, equipment and structures.

The main disadvantages of the above methods are the complexity of the devices, the significant cost of diagnostic devices, the lengthy training of personnel, as well as the inability to use corrosion diagnostic methods, due to the design features of the investigated object or the need to withdraw the object from the process.

Known RF patent for the invention No. 2511787 IPC F17D 5/02 "Marker for in-line diagnostics." The invention relates to magnetic in-line diagnostics and can be used in the oil and gas industry when determining the coordinates of defects in metal pipes of underground pipelines. The marker consists of two marker pads made of a ferromagnetic material, namely a pre-magnetized composite material with high plastic properties, mounted on top of the pipeline with a certain distance between them. The marker also contains milestones with an informational pointer. Pads are fixed due to the force of magnetic interaction between the pad and the steel pipe, and a milestone with an information indicator is installed in the ground when filling the pipeline. The technical result is to reduce the mass of the marker and the complexity of its installation, as well as improving the quality of installation and the reliability of its work.

The disadvantage of this invention is that to eliminate the risk of damage to the label, it is necessary to install an information indicator, for example, a flag, in addition, during natural disasters (hurricane, hail, etc.), the label can shift due to strong mechanical stress.

Closest to the claimed method is a USSR patent for the invention No. 1226171 "Method for determining the wear of parts of an internal combustion engine." On the wear surface of a part, for example, a piston ring, several marks with various radioactive isotopes are evenly placed. The number of labels, the order of their placement, and the composition of the isotopes are chosen so that the penetration of radiation quanta from neighboring labels through the backs of the collimator can be neglected. The initial radiation intensities from the isotopes of the marks in the selected intervals are measured and their relationship with the thickness of the marks is established. The determination of the radiation intensity is carried out according to the characteristics of the energy spectra of the radiation of individual isotopes, using a radiation analyzer. After that, the engine is operated for a predetermined time. Then the engine is stopped and the piston is set to top dead center. A scanner with a narrow angular collimation is moved over the cylinder head along the trajectory of the marks and the position of one of the marks is set, the isotope of the mark is determined by the type of radiation and the wear of the piston ring is determined by the change in the total radiation intensity of the mark. By sequentially moving the scanner over known distances, the wear of the piston ring at the locations of the marks is determined by the trajectory of the marks.

The disadvantage of this invention is the complexity in hardware design and limiting the variety of labels. These methods are expensive and time consuming. They are suitable for use in the laboratory, on test benches, but do not have field applications, in addition, RFID tags are limited in variety and cannot be used in large-sized products and areas. A major problem is also the need to shut down equipment.

Disclosure of invention

The objective of the proposed method for monitoring corrosion processes is to create a low-cost, informative, reliable and efficient method for determining the dislocation and the propagation rate of corrosion defects in real time, fully protected from the external environment and requiring a minimum of additional equipment for fixing the mark, while not requiring equipment stopping.

The problem is solved due to the fact that the method of monitoring corrosion processes includes the installation of labels, fluid selection and control indicators. The label is set on the inner surface of the test object. The label is selected with the possibility of applying to a metal surface to ensure resistance to the working fluid, the absence of analogues in the composition of the working fluid, biological and chemical inactivity in relation to the working fluid and the surface on which the mark is applied, as well as ensuring the stability of the label against barothermal effects. After that, the label is applied to predefined areas of the investigated object. They are put into operation, filling with a working fluid. After the start of the corrosion process, the mark applied to the areas subjected to corrosion, together with particles of metal or anti-corrosion coating of the areas subjected to corrosion, peels off the object. Then the label enters the fluid sampling zone to control the concentration of the labels, which determine the presence and interval in which corrosion and the intensity of the corrosion process occurred. Different pre-identified areas of the object are marked with different identification tags. The corrosion rate is determined by the concentration of the number of labels in the research process. As a label, choose fluorescent substances, or indicators of a radical type, or substances with a high absorption of thermal neutrons, or radioactive isotopes, or colored substances. The label is applied to the maximum area of possible corrosion.

The implementation of the invention

One of the types of marks is applied to the internal cavity of the tank, technological apparatus, pipe products, including at the joints, followed by coating with a protective material. With the thinning of the protective coating, due to the influence of aggressive factors of the working environment, labels (tracer markers) are released. The content in the samples of the working fluid of control marks determines the presence, the interval in which corrosion occurred and its intensity. This invention can be used, in particular, for:

- determining the time, extent and localization of the destruction interval of the protective coating or surface layer;

- optimizing the costs of maintenance and inspection;

- control of inaccessible areas subject to corrosion. Sampling methods:

GOST 2517-2012 Oil and petroleum products. Sampling methods, standardizes sampling methods from all types of containers, reservoirs of any kind, car and railway tanks. The equipment is subject to unification, which includes, first of all, samplers with the specifics of oil products and tanks, in particular:

- stationary

- portable

- samplers for the selection of liquefied petroleum gases (GOST 14921-78 liquefied hydrocarbon gases. Methods of sampling.) and various tanks with pressure products

The methodology concretizes sampling in vertical, horizontal, ice-ground storage facilities, tanks, including hidden underground, in trenches, tankers, tankers, etc.

Samples are placed in special bottles that are resistant to aggressive environments, hermetically sealed with a cork or screw cap, wrapped with a dense material for safety, tied with twine, and sealed. The label indicates all the required product information and information about the persons who took the sample.

Usually two samples are made, one of which goes to the laboratory, and the other is stored for arbitration analysis (it is called arbitration). Arbitration analysis can be made upon presentation of claims for oil quality.

The rules for sampling petroleum products also provide for: compliance with safety and fire safety standards, MPE standards (GOST 12.1.005-88 General sanitary and hygienic requirements for air in the working area.), Material of the samplers, the behavior of the sampler according to the instructions, etc.

To implement the method for monitoring corrosion processes, the following types of labels can be used:

Tags (tracer markers), various substances that differ in the identification method:

- fluorescent substances (rhodamine, fluorescein sodium, disodium salt of eosin, erythrosine, etc.), substances used for acid-base titrations of turbid or highly colored solutions, in which when illuminated with UV rays, at a certain pH value , fluorescence appears (or disappears) or its color or hue changes.

- indicators of the radical type (urea, ammonia sulfur, stable nitroxyl radicals and their derivatives (amines, amine salts)). - Used in the form of indicators of compounds from the class of nitrogenous, stable nitroxyl radicals. Widely tested in Tatarstan, Bashkiria at 15 fields. Indicators of the radical type are stable nitroxyl radicals that dissolve well in formation and injection water, have no analogues in nature, are biologically inactive (environmentally friendly), do not chemically interact with oil, are stable in formation conditions, and allow creating a range of indicators with similar physicochemical properties and a single registration method. As indicators of the radical type, triacetonamine, triacetonamine benzoate, etc. are used. This technology can be applied at a temperature of not more than 70 ° C.

- substances with a high absorption of thermal neutrons (for example, chlorine, rhodon, solutions of barium salts, boron, cadmium, rare earth elements)

- radioactive isotopes (for example, tritium - with a long half-life). - To detect a radioactive isotope conduct registration of the curves of HA. The choice of isotope is determined by the physicochemical properties of these isotopes. For injection of isotopes, deep injectors are used. For work, short-lived isotopes are selected that are not adsorbed by the rock. Before injection into the well, background measurement of the HA is necessarily done. The most widely tested tritium, isotope iodine-131.

Table 1 presents the conditions for the applicability of stable labels.

The use of radioactive isotopes as labels in industry is also known. One example of this is the following method for controlling the wear of piston rings in internal combustion engines. By irradiating the piston ring with neutrons, they cause nuclear reactions in it and make it radioactive. When the engine is running, particles of the ring material enter the lubricating oil. Examining the level of radioactivity of the oil after a certain engine running time, wear of the ring is determined. Radioactive isotopes allow us to judge the diffusion of metals, processes in blast furnaces, etc. These tags can also be used as tags for the implementation of the proposed method.

Applicable types of chemical labels (tracer markers)

- fluorescent tracers;

- ion tracers;

- organic tracers.

Distinguish color labels - color; glows - chemiluminescent and fluorescent; labels for the formation of a heterophase (in a particular case, a precipitate) and changes in its properties - sediment-forming, turbidity and adsorption. Of these indicators, color marks are most often used.

Labels (tracer markers) are used to identify factors associated with their presence, i.e. to determine the fluid flowing in a particular area, mark the fluid in the tanks.

Equipment and technologies for identifying tags are different, according to the selected tags by characteristics.

For example, equipment for determining the presence and concentration of radical type tags, fluorescent or color tags use the KAPEL®-105M CAPILLARY ELECTROPHORESIS SYSTEM.

Capillary Electrophoresis CE (Capillary Electrophoresis, CE) is a separation method implemented in capillaries and based on differences in electrophoretic mobilities of charged particles in both aqueous and non-aqueous buffer electrolytes. Buffer solutions (leading electrolytes, working buffers, background electrolyte, run buffer) can contain additives (for example, macrocycles, organic solvents, polymers, etc.) that can interact with the analyzed particles and change their electrophoretic mobility.

The main distinguishing feature of the KAPEL®-105M model is spectrophotometric detection. A deuterium lamp is used as a light source, and a diffraction monochromator with a spectral range of 190-380 nm and a spectral interval width of 20 nm is used as a dispersing element. This range allows you to select the detection wavelength that is most sensitive to the target components, which facilitates the development of new techniques and in many cases reduces the detection limit.

There are also other specialized laboratory instruments and techniques for determining selected labels (tracer markers) in substances.

An example implementation of the proposed method

The developers of the method for monitoring corrosion processes conducted tests that prove the industrial applicability of the method.

The tests were conducted in November 2016 at the production base of KomiSeverTransit LLC. Testing was agreed with KomiSeverTransit LLC on 09.11.2016.

Equipment for installing test samples was provided by KomiSeverTransit LLC. The equipment was installed by specialists of KomiSeverTransit LLC.

Tags (tracer markers) were selected according to the following criteria:

1. Unique features to highlight

2. Environmental and sanitary-epidemiological safety

3. High sensitivity, with low material consumption

4. The absence of a chemical reaction with the pumped medium

5. Low cost and market availability

6. The ability to simultaneously determine different labels for one sample

7. Ability to identify markers using available analysis methods

As labels, we chose carbamides that were deposited on sample 1 (a steel pipe with a thread diameter of 73 mm and a length of 50 cm) and ammonium rhodanides that were deposited on sample 2 (steel pipe with a diameter of 73 mm and a length of 50 cm).

Sample 1 was installed on the flow line of a pump located in the pump room using adapter pipes.

At the entrance to the heating radiator located in the warehouse, Sample 2 was installed by means of adapter pipes.

After the installation of samples 1, 2, the equipment was put into operation and put into constant operation.

Urea - urea - a label, which is a white crystalline substance. Urea crystallizes from water in the form of flat prisms, readily soluble in alcohol and water, melting at a temperature of 160-190 ° C. When heated to 200 ° C, this compound turns into ammonium cyanate, and under the influence of higher temperatures at atmospheric pressure, urea decomposes with the formation of carbon dioxide, ammonia, cyanoic acid, biuret and other components. Nitrogen in the urea is in the easily digestible amide form. Amide nitrogen is well absorbed by the leaves and roots of plants.

Ammonium thiocyanate is a label that dissolves in ethyl and methyl alcohol, liquid ammonia, acetone. The substance is combustible, when heated above + 140 ° C it turns into thiourea, at t + 170 ° C it decomposes completely.

As a protective layer for sample 1 and sample 2, two layers of anticorrosion coating based on epoxy powder paints were chosen.

A drain valve located in the direction of flow, after the installation sites for samples No. 1, 2, was determined as the sampling site. The content of markers was monitored by a Capell-105 / 105M capillary electrophoresis system.

Before installation, additionally carried out measurements:

1. Flow rate

2. The temperature of the coolant

3. The presence of tracer markers

Sampling was carried out on the first day every four hours, on the following days once a day.

At the time the label (tracer marker) appeared in the samples, fluid transfer was stopped and a visual assessment was made of the state of the protective layer of the sample, the label of which was identified. After this, the pumping process was started again, before the label of sample 2 appeared. Next, a thorough visual examination of the state of the protective layer on both samples was carried out.

As a result of experimental tests, the following results were obtained, presented in table 2:

The costs of the pilot tests amounted to: 18,000 rubles.

Conclusion

According to the results of experimental tests, it is clear that the operability of the method of monitoring corrosion processes through the use of labels (marker tracers) is fully confirmed.

Thus, potential fields of application are all sectors of economic activity in which equipment and materials are used, the inner surface of which is susceptible to corrosion processes.

The advantages of the proposed method for monitoring corrosion processes:

- the ability to localize the place of corrosion;

- the possibility of implementing the method without stopping the equipment for work and without removing the equipment from the process;

- the possibility of implementation for a wide range of equipment;

- the possibility of implementing the method in virtually any external and internal environment;

- the possibility of more detailed and effective planning of work to identify corrosion violations, timely repair or replacement;

- optimization of operating expenses;

- low cost of the method;

- the ability to control the corrosion processes of engineering networks and technological equipment, in real time and where until now, timely identification of corrosion processes was not available.

The task, the creation of a method for monitoring corrosion processes low-cost, informative, reliable and effective method for determining the dislocation and the propagation rate of corrosion damage in real time, fully protected from the effects of the external environment and requiring a minimum of additional equipment for fixing the label, while not requiring equipment stop .

Industrial applicability is proved by experimental tests conducted by the authors at the production base of KomiSeverTransit LLC, Usinsk, Komi Republic.

Claims (5)

1. A method of monitoring corrosion processes, including the installation of a label, characterized in that the label is installed on the inner surface of the test object, and the label is selected with the possibility of applying to a surface subject to corrosion or destruction, ensuring resistance to the working fluid and ensuring the absence of analogues in the composition of the working fluid, biological and chemical inactivity in relation to the working fluid and the surface on which the label is applied, as well as ensuring the stability of the label to baroter impact, after which the mark is applied to predetermined sections of the test object, after which the object is put into operation, filled with a working fluid, and after the corrosion process begins, the mark applied to the areas subjected to corrosion or destruction, together with metal particles or the anticorrosion coating that covered the layer with marks peels off the object, then the label goes into the fluid selection zone to control the concentration of marks that determine the presence, the interval in which corrosion occurred , and the intensity of the corrosion process. 2. A method for monitoring corrosion processes according to claim 1, characterized in that different identification marks are applied to different previously designated areas of the object. 3. The method of monitoring corrosion processes according to claim 1, characterized in that the corrosion rate is determined by the concentration of the number of labels in the research process. 4. A method for monitoring corrosion processes according to claim 1, characterized in that color and fluorescent substances, or indicators of a radical type, or substances with high absorption of thermal neutrons, or radioactive isotopes, are selected as a label. 5. A method for monitoring corrosion processes according to claim 1, characterized in that the label is applied to the maximum area of possible corrosion.