RU2685055C1 - Method for monitoring carbon-dioxide corrosion in trade gas pipelines and device for its implementation - Google Patents

Abstract

FIELD: transportation.SUBSTANCE: invention is related to the field of failure-free operation of trade pipelines transporting raw gas, and can be used for monitoring of pipelines corrosion developing as to carbon-dioxide type. Method of monitoring carbon dioxide corrosion in trade gas pipelines includes measuring parameters of transported medium by means of corrosion rate sensors, which implement method of electrical resistance and method of linear polarization resistance as corrosion rate sensor, implementing method of linear polarization resistance, corrosion parameter meter is used with assessment of medium mineralization. In close proximity to each other, three corrosion rate sensors are installed, measuring probe of the first sensor, which realizes electric resistance method, is located in central part of gas pipeline, measuring probe of a second similar sensor and a measuring probe of a sensor which realizes a linear polarization resistance method are installed flush with the lower generatrix of the gas line, information outputs of corrosion rate sensors are connected to the telemetry system according to their resident interfaces, in the absence of carbon dioxide-type corrosion, two sensors, which realize the electrical resistance method, will have identical readings, and the sensor, which realizes the linear polarization resistance method, will indicate zero corrosion rate, in the presence of intense condensation of mineralized water and formation of a stream along the lower generatrix, sensor, which realizes the method of linear polarization resistance, will start to give readings of corrosion rate, different from zero values, and certain level of medium mineralization, sensor, which realizes the electric resistance method and is installed flush with the lower generatrix of the gas pipeline, will fix a considerable increase in the corrosion rate compared to the previous values and the readings of the sensor installed in the pipe center, combination of data on mineralization of medium and data from sensors of corrosion rate enables to judge intensity of developing corrosion.EFFECT: technical result is rapid monitoring of corrosion of field gas pipelines flowing along carbon-dioxide type.2 cl, 3 dwg

Description

The present invention relates to the field of ensuring trouble-free operation of field pipelines transporting raw gas, and can be used to monitor the corrosion that develops in carbon dioxide type. A known method of controlling corrosion inside pipelines, more precisely, in its bottom part. According to this method, cylindrical samples of carbon steel, collected in cassettes of 10 pieces, are placed in a pipeline, in contact with its lower generatrix. Between all samples in the cassette there is a reliable electrical contact. When water is separated in a pipeline in a separate phase, and the cassette is completely in the water sublayer, then all samples in the cassette have the same stationary electrode potential. Therefore, with certain assumptions, such a cassette assembly from an electrochemical point of view can be considered one “piece” of metal. After exposure in the pipeline (from 7 to 40 days), the corrosion rate is determined by the mass loss separately for each sample and the average speed of the cassette is found as the average for all samples (see A. Markin, R. Nizamov. CO ₂ - corrosion oil field equipment. - Moscow: VNIIOENG JSC. - 2003. - 188 s, p. 48).

The disadvantages of the method: the inertia in detecting the onset of an intensive corrosion process and the complexity of data acquisition.

Of the known ones, the closest in technical essence is a method for monitoring pipeline corrosion, which includes measuring environmental parameters using sensors located at observation points in accordance with measurement cards and pipeline corrosion rates, using a pipeline corrosion monitoring device to measure these parameters, including the first physical condition diagnostics module a pipeline designed to be located inside the pipeline, and a second physical state diagnostic module a pipeline designed to be located outside the pipeline, an interface unit of these modules with an industrial Ethernet network, at least two corrosion rate measurement channels, each of which has a corrosion rate meter connected in series, an interface unit and a controller that is connected to an industrial Ethernet network , a pipeline corrosion monitoring control panel, a database server and a server that converts Ethernet network data into a form that each controller can understand (see RU 2459136, IPC F16L 58/00, G01N17 / 00. METHOD OF MONITORING CORROSION OF A PIPELINE AND A DEVICE FOR ITS IMPLEMENTATION / Valery Goncharov (RU)).

This method is taken as a prototype. The disadvantage of the method, taken as a prototype, is the lack of an algorithm for analyzing data from sensors, as well as their constructive adaptation for the implementation of monitoring of corrosion developing in a carbon-dioxide type.

From the patent literature is known "Measuring polarization resistance" (AB. St. SU 960638, G01R 17/10, publ. 23.09.82), containing a two-electrode transducer. This device can be used to determine the rate of electrochemical corrosion of metals. The disadvantages of the device are: a limited amount of measurement information and insufficient functionality to perform monitoring tasks.

The closest to the totality of the signs to the claimed device is "Measuring parameters of corrosion" (patent RU 2225594 IPC 7 G01D 9/00, G01N 17/00, G01N 27/20; claimed. 04/21/2003; publ. 10.03.2004) containing a sensor - a primary converter of informative values into electrical signals, a non-volatile memory module and a power supply located in a housing, an electrical connector, a temperature sensor, a preliminary signal processing unit whose output is connected to the input of a multichannel analog-to-digital converter (MACP), including an ultiplexer and an ADC, as well as a microprocessor, including a controller, random access memory, and a real-time timer, placed in the case of the second electrical connector, power controller, keyboard, LCD display, real-time clock, and heating element, the microprocessor being connected to the unit signal processing, a liquid crystal display, and corresponding bilateral ties - with the MAC, keyboard, real time clock, yes The temperature controller, power controller and the first electrical connector, which is connected in parallel with the digital outputs of the MACP with its information outputs, the second electrical connector are connected by bilateral connections to the signal pre-processing unit, the power controller with its three control outputs, respectively, is connected to the first electrical connector, the heating element and the preliminary signal processing with a liquid crystal display, the power source is connected to the corresponding etstvuyuschim feed temperature sensor inputs, the real time clock, Matzpen. microprocessor, as well as a power controller, a non-volatile memory module connected by double-sided connections to the first electrical connector, the housing with functional blocks and elements placed in it are placed in a sealed protective box equipped with a third electrical connector, inputs connected via a cable to the sensor — the primary converter of informative values into electrical signals, and exits through a cable located inside the box with a second electrical connector.

This device is taken as a prototype. Its disadvantages are also the limited amount of measurement information received and insufficient functionality to perform monitoring tasks.

Summary of Invention

The present invention relates to a method for monitoring carbon dioxide corrosion in field pipelines, namely that measurements of the parameters of the transported medium are made by means of corrosion rate sensors implementing the electrical resistance method and the linear polarization resistance method, and three sensors are installed in close proximity to each other corrosion rate, the measuring probe of the first sensor that implements the method of electrical resistance, have In the central part of the pipeline, the measuring probe of the second similar sensor and the measuring probe of the sensor implementing the linear polarization resistance method are installed flush with the lower generator of the pipeline, the information outputs of the corrosion rate sensors are connected to the telemetry system according to their resident interfaces, in the absence of corrosion by carbon dioxide type, two sensors that implement the electrical resistance method will have identical readings, and a sensor that implements the linear resistance method polarization, will indicate a zero corrosion rate, in the presence of intense condensation of saline water and the formation of a stream along the lower generatrix, a sensor implementing the linear polarization resistance method will begin to give a corrosion rate reading different from zero and a certain level of mineralization of the medium; a sensor implementing the electric method resistance and installed flush with the lower part of the pipeline, will fix a significant increase in corrosion rate in comparison with the previous by their values and indications of the sensor installed in the center of the pipe, the combination of data on the mineralization of the medium and data from the corrosion rate sensors allows us to judge the intensity of the flowing corrosion.

The present invention also relates to a corrosion parameter meter with an assessment of the mineralization of the medium, comprising a sensor — a primary converter of informative values into electrical signals, a non-volatile memory module and a power source, electrical connector, temperature sensor, signal pre-processing unit located in the housing, the output of which is connected to the input multichannel analog-to-digital converter (MAT), including a multiplexer and ADC, as well as a microprocessor, including a controller, opera A tive memory device and a real-time timer are placed in the case of the second electrical connector, power controller, keyboard, LCD display, real-time clock and heating element, with the microprocessor connected by corresponding one-way connections to the signal preprocessing unit, liquid-crystal display with MACP, keyboard, real time clock, temperature sensor, power controller and first electrical connection the telecom, which is connected in parallel with the digital outputs of the MACP with its information outputs, the second electrical connector is connected to the preprocessing unit of signals by a double-sided connection, the power controller, with its three control outputs, respectively, is connected to the first electrical connector, the heating element and the preprocessing unit of the signals power supply is connected to the corresponding power inputs of the temperature sensor, real time clock and, the MACP, the microprocessor, as well as the power controller, a non-volatile memory module connected by double-sided connections to the first electrical connector, the housing with functional blocks and elements placed in it are placed in a sealed protective box equipped with a third electrical connector, connected via cable with sensor the primary converter of informative values into electrical signals, and the outputs through the cable inside the box with the second electrical connector, according to the invention In addition, a permanent memory device (ROM), an interface for communication with the telemetry system, two fourth and fifth electrical connectors, the microprocessor is connected by corresponding one-way connections to the ROM input and output data of the ROM, and a fourth electrical connector is connected to the interface. corresponding bilateral connections with the interface and corresponding bilateral relations through the fifth electrical connector and located on the wall behind shield box, with telemetry system, interface power supply and ROM are connected to the power supply.

The inventive method is based on this device, performing the function of a corrosion sensor that implements the method of resistance to linear polarization.

The combination of new features with known allows in the present invention to solve the technical problem:

- operational monitoring of corrosion of gas pipelines flowing through the carbon dioxide type.

The invention is illustrated by the description and drawings, where Fig 1 shows a block diagram of a corrosion parameter meter with an assessment of the salinity of the medium; in fig. 2 - implementation of the method for monitoring carbon dioxide corrosion in field pipelines; The photo (Fig. 3) shows examples of corrosion damage in the lower part of the gas field pipeline.

FIG. 1 and FIG. 2 indicates the following:

1 - sensor - the primary converter of informative values into an electrical signal (probe);

2 - probe cable;

3 - housing;

4 - the first electrical connector;

5 - block preprocessing signals;

6 - multichannel analog-to-digital converter (MATD);

7 - multiplexer;

8 - analog-to-digital converter (ADC);

9 - microprocessor;

10 - the controller;

11 - random access memory (RAM);

12 - real-time timer;

13 - power supply;

14 - real time clock;

15 - temperature sensor;

16 - power controller;

17 - keyboard;

18 - liquid crystal display;

19 - heating element;

20 - the second electrical connector;

21 - non-volatile memory module;

22 - sealed protective box;

23 - the third electrical connector;

24 - cable in a protective box;

25 is a permanent storage device;

26 - interface for communication with the telemetry system;

27 is the fourth electrical connector;

28 - the fifth electrical connector;

29 - cable in protective box;

30 - section of the gas pipeline, on which the probes of the corrosion rate sensors are installed;

31 - the flow of the transported medium;

32 - probe of the corrosion rate sensor, implementing the method of electrical resistance (ES);

33 - probe of the corrosion rate sensor implementing the method (ES) and installed flush with the lower generator of the gas pipeline;

34 is a sensitive element of the probe 33;

35 - probe speed corrosion sensor that implements the method of resistance to linear polarization (SLP);

36 - probe element 35;

37 - sensor measuring transducer that implements the ES method;

38 - sensor measuring transducer that implements the ES method;

39 - sensor measuring transducer that implements the method of PLC;

40 - communication line with telemetry system. Device operation

The principle of operation of the device is based on the method of linear polarization (synonymous with the method of "polarization resistance"). Indirect measurements of the corrosion rate Vc are obtained by measuring the polarization resistance Rmp and implementing the following computational procedure:

V = K VaVk / S / (Ba + Vk) / Rmp,

where K, S, Ba, Bk are the settings programmed from the keyboard for specific conditions of use: the material of the probe electrodes, their area, the parameters of the corrosive environment.

For a two-electrode probe, the Rmp value is obtained as the resistance to the flow of current between them (electrodes) when a small polarizing voltage is applied (no more than 20 mV) minus the resistance of the analyzed medium (electrolyte). Usually information about the resistance of the medium is no longer required. In the present invention, it is used to assess the salinity of the medium, and, given the carbon dioxide mechanism of corrosion in the field gas pipeline, is an important component of the measurement information on the course of the corrosion process. The function of the measuring channel of the mineralization of the environment is realized on the ROM 25. Where the address inputs come from the microprocessor 9 information about the resistance of the environment, and the value of mineralization is taken from the corresponding data cells of the ROM. Thus, the ROM 25 acts as a functional converter. In the relevant technical literature, information on functional dependence: mineralization — specific conductivity (or resistivity of the medium) is widely represented. The required dependence can be obtained under laboratory conditions, simulating the conditions of the intended object of measurement. The necessary data in the ROM is entered during the manufacture of the device. The basic measuring circuit (without the channel of mineralization) is implemented in serial devices: "Corrosimeter AkCord LPR RAST.427678.401" and "Corrosimeter Akkord LPR RAST.427678.402" (produced by NPP SONAR), which have been manufactured since 2003.

An example of the method implementation is shown in FIG. 2, which depicts a fragment of the field gas pipeline 30 through which the transported product 31 passes. In the central part of the gas pipeline, a probe 32 is installed which implements the EC method. Here the most acceptable configuration of the sensitive element of the probe is cylindrical or tape. On the lower generatrix, in the immediate vicinity of the probe 32, a probe 33 of the second sensor is installed, which implements the EC method. The sensing element 34 it should have a flat configuration - for installation flush with the lower generatrix. The probe 35 of the sensor that implements the method of PSL is installed side by side, also flush. The preferred configuration of the probe electrodes 36 is disk. As measuring transducers 37, 38 sensors that implement the EU method, the Microcor MT-9485A (manufactured by RCS, USA) or the domestic instrument AkRord ER RAST.427678.407 (manufactured by NPP SONAR LLC since 2012 can be used) of the year). Both devices have resident RS-485 physical layer interfaces and can be easily connected to the telemetry system via line 40. The functions of the measuring transducer 39 implementing the PLC method are assigned to a corrosion parameter meter with a salinity estimate shown in FIG.

The method is as follows. If intensive condensation of water and flow (or, more correctly, film) does not occur along the lower gas line, the electrodes 36 of the probe 35 are not covered with a conductive medium, as a result of which the readings of the measuring transducer 39 implementing the LPS method will be zero. When changing the conditions of gas transportation, leading to intensive condensation of water, the electrodes of probe 35 will be completely covered with saline water, and the measuring transducer 39 will begin to register non-zero values of the corrosion rate and salinity of the medium. At the same time, the measuring transducer 38, which implements the ES method, whose probe 33 is located next to the probe 35, will show a significant increase in corrosion rate compared to previous values and readings of the measuring transducer 37, the probe 32 of which is located on the axis of the pipeline. The use of two methods of PSL and ES to measure the corrosion rate in saline water makes it possible to verify the results obtained - to check their truth, and the combination of the obtained values of water salinity and corrosion rates at various points (bottom, middle) of the gas pipeline - to predict the nature of the developing corrosion. Fig 3 presents a view of corrosion damage in the lower part of the pipeline, due to the flow of saline water. With weak mineralization, local corrosion is noticeable, but not catastrophic (Fig. 3, photos a and b). With the growth of mineralization and the duration of exposure of the liquid medium to the pipeline, the outcome is through ulcers (Fig 3, photo b).

If the conditions in the gas pipeline change and the water ceases to form a continuous film on the lower part of it, it will be visible not only from the readings of the measuring transducer 39, but also when comparing the measurement results of two measuring transducers 37 and 38 - after some time their readings should become close - the same is verification.

Thus, the proposed method provides the ability to quickly monitor the corrosion of gas pipelines flowing through the carbon dioxide type.

Claims (2)

1. Measuring corrosion parameters with an assessment of the mineralization of the environment, containing a sensor — a primary converter of informative values into electrical signals, a non-volatile memory module and a power source, electrical connector, temperature sensor, preliminary signal processing unit whose output is connected to a multichannel analog input located in the housing digital converter (MACP), including a multiplexer and ADC, as well as a microprocessor, including a controller, random access memory and time real time, placed in the case of the second electrical connector, power controller, keyboard, liquid crystal display, real time clock and heating element, and the microprocessor is connected by corresponding one-sided connections to the signal preprocessing unit, liquid crystal display, and corresponding two-way connections - to the MACP, keyboard, real time clock, temperature sensor, power controller and the first electrical connector, which by its informational The outputs are connected in parallel to the digital outputs of the MACP, the second electrical connector is connected to the preprocessing unit, the power controller with its three control outputs, respectively, is connected to the first electrical connector, the heating element and the preprocessing unit together with the liquid crystal display, the power supply is connected to the corresponding power supply inputs of temperature sensor, real time clock, MACP, microprocessor, and control power supply, nonvolatile memory module, connected by bilateral connections to the first electrical connector, the housing with functional blocks and elements placed in it are placed in a sealed protective box equipped with a third electrical connector, inputs connected via a cable with a sensor - a primary converter of informative values into electrical signals, and the outputs through the cable inside the box - with a second electrical connector, characterized in that it is additionally entered permanently This memory device (ROM), an interface for communication with the telemetry system, two electrical connectors, the fourth and fifth, and the microprocessor is connected by corresponding one-way communications to the address input and output of these ROMs, and the fourth electrical connector is connected by corresponding two-way connections. connections with the interface and the corresponding bilateral connections through the fifth electrical connector located on the wall of the protective box - with the teleme system The three power supply circuits of the interface and the ROM are connected to the power supply. 2. A method for monitoring carbon dioxide corrosion in field pipelines, including measuring the parameters of a transported medium by means of corrosion rate sensors implementing an electric resistance method and a linear polarization resistance method, characterized in that the device according to the linear polarization resistance method uses a polarization resistance method . 1, in close proximity to each other, three corrosion rate sensors are installed, the measuring probe of the first sensor, In the central part of the pipeline, the measuring probe of the second similar sensor and the measuring probe of the sensor implementing the linear polarization resistance method are installed flush with the lower generator of the pipeline, the information outputs of the corrosion rate sensors are connected to the telemetry system according to their resident interfaces, in the absence of corrosion on carbon dioxide type two sensors that implement the method of electrical resistance will be identical readings, and a sensor that implements the linear polarization resistance method will indicate a zero corrosion rate, in the presence of intense condensation of saline water and a flow along the lower generatrix, a sensor that implements the linear polarization resistance method will start to give a corrosion rate reading different from zero, and a certain level of mineralization of the environment, a sensor that implements the method of electrical resistance and installed flush with the lower generator of the pipeline, will fix achitelnoe increase in the corrosion rate compared to previous values and sensor readings, installed in the center of the tube, the combination of the salinity of the environment and the corrosion rate data from the sensors enable to judge the intensity of the developing corrosion.

Images