Corrosion monitoring

Last updated

Corrosion monitoring is the use of a corrator (corrosion meter) or set of methods [1] and equipment to provide offline or online information about corrosion rate expressed in mpy (mill per year). [2] - for better care and to take or improve preventive measures to combat and protect against corrosion. In this article, the difference between corrosion monitoring and corrosion protection, its difference with corrosion inspection and also the relationship between them, as well as online corrosion monitoring methods, equipment used and applications of each of them, are presented.

Contents

Corrosion protection or corrosion monitoring

Various methods are used to prevent and protect against corrosion, such as cathodic protection, selection and injection of chemicals such as corrosion inhibitors or other ways to prevent corrosion. However, in order to see the results of these methods and how effective these measures are, corrosion monitoring should be done and, if necessary, corrosion protection methods should be modified or optimized based on the results obtained from corrosion monitoring. In many industries, preventive measures are used to protect against corrosion, but obviously without knowing the results of these measures, protection is a chance, that is, either full protection will not be done or in case of excessive protection, it will waste capital and resources.

The difference between corrosion inspection and corrosion monitoring

There may be a general misconception between the term corrosion inspection and corrosion monitoring, but inspection means frequent checkpoints to check for changes or deviations from predicted results, while corrosion monitoring is a continuous check to control and act quickly against change. In inspection, the purpose is to evaluate or estimate the corrosion time in order to replace or correct the corrosion, while in corrosion monitoring, the purpose is to take care of the change in order to prevent corrosion and to improve the ways of prevention. [3]

Online corrosion monitoring methods

Online corrosion monitoring is mostly done using the following methods: [3]

Use of weight loss coupons

Corrosion coupons are made in different shapes and sizes. These coupons are often made from same material of the pipe or tank/vessel which should be monitored for corrosion. The most common used coupons are as follows:

Use of electrical resistance (ER) corrosion probes

Electric resistance corrosion probes are used in different types for different applications of online corrosion monitoring. The corrosion rate of these probes can be measured online or transferred to the control system by using corrosion handheld or fixed data loggers or by corrosion transmitters. The general type of ER probes element are as below:[ citation needed ]

ER probes can be provided by adapter in order to connect to data logger or transmitters. The length of probes is dependent on the mounting and monitoring position.

Use of linear polar resistance probes

This method is mostly used for corrosion monitoring in water industry. These probes are suitable for monitoring fluctuations that may occur in a fluid inside the system. These probes are mostly used for conductive fluids such as water or any similar else.

Use of online ultrasonic thickness sensors

Online non-intrusive ultrasonic thickness sensors are a popular choice for corrosion monitoring in various industries, including oil and gas, chemical processing, and power generation. These sensors can provide accurate and reliable thickness measurements of metal structures without requiring physical access or disruption to the equipment. The sensors can be installed permanently and remotely connected to a monitoring system, allowing for continuous data collection and analysis. With the ability to detect corrosion early on, online ultrasonic thickness sensors can help prevent equipment failure, reduce downtime, and improve overall safety and efficiency.

Use of hydrogen probes

Hydrogen probes are used to monitor the penetration of hydrogen into steels, which can cause brittleness, porosity or decarbonization. [5]

Using a sand probe

These probes are mostly used to monitor corrosion caused by erosion or wear. Generally, the erosion are occurred in gas pipelines where the speed of fluid cause erosion. Here the erosion is more important than corrosion.

Use a biological probe or bio-probe

Biological probe or bio-probes are used to collect samples for microbiological analysis. Microorganisms can accelerate the corrosion process, so monitoring the corrosion caused by them is effective in timely notification and preventive measures.

Main equipment of corrosion monitoring system

In addition to probes, the items below are the main ones used in corrosion monitoring: [6]

Access fittings

The access fittings - such as flanged, flare-weld, etc.- are used for connection and access to coupons and probes. The general size of A/F is 2" which is called 2" system. But for small pipe sizes, 1" system can be used.

Coupon holder

Coupon holders are used to fix corrosion coupons inside a pipe or tank and attaches itself to a solid plug or hollow plug. They are usually made from stainless steel 316/316L or Monel and inconel or other corrosion resistant materials. [7]

Service valve

Service valve is a ball type used to block fluid while replacing corrosion coupons or probes despite fluid flow. The service valve is attached to solid or hollow plug after removing of access fitting cover. It blocks the fluid while the coupon or probe is retrieved by retriever and passed through it.

Retriever for retrieval without process interruption

Retriever is used to insert and retrieve coupons and probes without interrupting the process. [8] They can be provided in hydraulic and mechanical types.

Related Research Articles

<span class="mw-page-title-main">Maintenance</span> Maintaining a device in working condition

The technical meaning of maintenance involves functional checks, servicing, repairing or replacing of necessary devices, equipment, machinery, building infrastructure, and supporting utilities in industrial, business, and residential installations. Over time, this has come to include multiple wordings that describe various cost-effective practices to keep equipment operational; these activities occur either before or after a failure.

Flow measurement is the quantification of bulk fluid movement. Flow can be measured using devices called flowmeters in various ways. The common types of flowmeters with industrial applications are listed below:

<span class="mw-page-title-main">Pigging</span> Practice of using pipeline inspection gauges or gadgets to perform various maintenance operations

In pipeline transportation, pigging is the practice of using pipeline inspection gauges or gadgets, devices generally referred to as pigs or scrapers, to perform various maintenance operations. This is done without stopping the flow of the product in the pipeline.

<span class="mw-page-title-main">Predictive maintenance</span> Method to predict when equipment should be maintained

Predictive maintenance techniques are designed to help determine the condition of in-service equipment in order to estimate when maintenance should be performed. This approach promises cost savings over routine or time-based preventive maintenance, because tasks are performed only when warranted. Thus, it is regarded as condition-based maintenance carried out as suggested by estimations of the degradation state of an item.

<span class="mw-page-title-main">Ultrasonic testing</span> Non-destructive material testing using ultrasonic waves

Ultrasonic testing (UT) is a family of non-destructive testing techniques based on the propagation of ultrasonic waves in the object or material tested. In most common UT applications, very short ultrasonic pulse waves with centre frequencies ranging from 0.1-15 MHz and occasionally up to 50 MHz MHz, and occasionally up to 50 MHz, are transmitted into materials to detect internal flaws or to characterize materials. A common example is ultrasonic thickness measurement, which tests the thickness of the test object, for example, to monitor pipework corrosion and erosion. Ultrasonic testing is extensively used to detect flaws in welds.

<span class="mw-page-title-main">Magnetic flux leakage</span> Non-destructive testing method

Magnetic flux leakage is a magnetic method of nondestructive testing that is used to detect corrosion and pitting in steel structures, most commonly pipelines and storage tanks. The basic principle is that a powerful magnet is used to magnetize the steel. At areas where there is corrosion or missing metal, the magnetic field "leaks" from the steel. In an MFL tool, a magnetic detector is placed between the poles of the magnet to detect the leakage field. Analysts interpret the chart recording of the leakage field to identify damaged areas and to estimate the depth of metal loss.

Level sensors detect the level of liquids and other fluids and fluidized solids, including slurries, granular materials, and powders that exhibit an upper free surface. Substances that flow become essentially horizontal in their containers because of gravity whereas most bulk solids pile at an angle of repose to a peak. The substance to be measured can be inside a container or can be in its natural form. The level measurement can be either continuous or point values. Continuous level sensors measure level within a specified range and determine the exact amount of substance in a certain place, while point-level sensors only indicate whether the substance is above or below the sensing point. Generally the latter detect levels that are excessively high or low.

<span class="mw-page-title-main">Phased array ultrasonics</span> Testing method

Phased array ultrasonics (PA) is an advanced method of ultrasonic testing that has applications in medical imaging and industrial nondestructive testing. Common applications are to noninvasively examine the heart or to find flaws in manufactured materials such as welds. Single-element probes, known technically as monolithic probes, emit a beam in a fixed direction. To test or interrogate a large volume of material, a conventional probe must be physically scanned to sweep the beam through the area of interest. In contrast, the beam from a phased array probe can be focused and swept electronically without moving the probe. The beam is controllable because a phased array probe is made up of multiple small elements, each of which can be pulsed individually at a computer-calculated timing. The term phased refers to the timing, and the term array refers to the multiple elements. Phased array ultrasonic testing is based on principles of wave physics, which also have applications in fields such as optics and electromagnetic antennae.

<span class="mw-page-title-main">Rail inspection</span>

Rail inspection is the practice of examining rail tracks for flaws that could lead to catastrophic failures. According to the United States Federal Railroad Administration Office of Safety Analysis, track defects are the second leading cause of accidents on railways in the United States. The leading cause of railway accidents is attributed to human error. The contribution of poor management decisions to rail accidents caused by infrequent or inadequate rail inspection is significant but not reported by the FRA, only the NTSB. Every year, North American railroads spend millions of dollars to inspect the rails for internal and external flaws. Nondestructive testing (NDT) methods are used as preventive measures against track failures and possible derailment.

Black powder is an industry name for the abrasive, reactive particulate contamination present in all gas and hydrocarbon fluid transmission lines. Black powder ranges from light brown to black, and the mineral makeup varies per production field around the world.

Pipeline leak detection is used to determine if and in some cases where a leak has occurred in systems which contain liquids and gases. Methods of detection include hydrostatic testing, tracer gas leak detection, infrared, and laser technology after pipeline erection and leak detection during service.

In the field of industrial ultrasonic testing, ultrasonic thickness measurement (UTM) is a method of performing non-destructive measurement (gauging) of the local thickness of a solid element based on the time taken by the ultrasound wave to return to the surface. This type of measurement is typically performed with an ultrasonic thickness gauge.

Hot plate welding, also called heated tool welding, is a thermal welding technique for joining thermoplastics. A heated tool is placed against or near the two surfaces to be joined in order to melt them. Then, the heat source is removed, and the surfaces are brought together under pressure. Hot plate welding has relatively long cycle times, ranging from 10 seconds to minutes, compared to vibration or ultrasonic welding. However, its simplicity and ability to produce strong joints in almost all thermoplastics make it widely used in mass production and for large structures, like large-diameter plastic pipes. Different inspection techniques are implemented in order to identify various discontinuities or cracks.

<span class="mw-page-title-main">Capacitive displacement sensor</span>

Capacitive displacement sensors are "non-contact devices capable of high-resolution measurement of the position and/or change of position of any conductive target". They are also able to measure the thickness or density of non-conductive materials. Capacitive displacement sensors are used in a wide variety of applications including semiconductor processing, assembly of precision equipment such as disk drives, precision thickness measurements, machine tool metrology and assembly line testing. These types of sensors can be found in machining and manufacturing facilities around the world.

<span class="mw-page-title-main">Guided wave testing</span>

Guided wave testing (GWT) is a non-destructive evaluation method. The method employs acoustic waves that propagate along an elongated structure while guided by its boundaries. This allows the waves to travel a long distance with little loss in energy. Nowadays, GWT is widely used to inspect and screen many engineering structures, particularly for the inspection of metallic pipelines around the world. In some cases, hundreds of meters can be inspected from a single location. There are also some applications for inspecting rail tracks, rods and metal plate structures.

Terahertz nondestructive evaluation pertains to devices, and techniques of analysis occurring in the terahertz domain of electromagnetic radiation. These devices and techniques evaluate the properties of a material, component or system without causing damage.

DCVG is a survey technique used for assessing the effectiveness of corrosion protection on buried steel structures. In particular, oil and natural gas pipelines are routinely monitored using this technique to help locate coating faults and highlight deficiencies in their cathodic protection (CP) strategies.

<span class="mw-page-title-main">Conservation and restoration of iron and steel objects</span>

Iron, steel, and ferrous metals constitute a large portion of collections in museums. The conservation and restoration of iron and steel objects is an activity dedicated to the preservation and protection of objects of historical and personal value made from iron or steel. When applied to cultural heritage this activity is generally undertaken by a conservator-restorer. Historically, objects made from iron or steel were created for religious, artistic, technical, military and domestic uses. Though it is generally not possible to completely halt deterioration of any object, the act of conservation and restoration strives to prevent and slow the deterioration of the object as well as protecting the object for future use. One of the first steps in caring for iron is to examine them and determine their state, determine if they are corroding, and consider options for treatment.

A density meter (densimeter) is a device which measures the density of an object or material. Density is usually abbreviated as either or . Typically, density either has the units of or . The most basic principle of how density is calculated is by the formula:

Robotic non-destructive testing (NDT) is a method of inspection used to assess the structural integrity of petroleum, natural gas, and water installations. Crawler-based robotic tools are commonly used for in-line inspection (ILI) applications in pipelines that cannot be inspected using traditional intelligent pigging tools.

References

  1. ↑ Corrosion Monitoring in Oil and Gas Production Maarten J.J. Simon Thomas; Sieger Terpstra Paper presented at the CORROSION 2003, San Diego, California, March 2003. Paper Number: NACE-03431 Published: March 16 2003
  2. ↑ "Corrosion rate - MPY - Mils per year - Conversion mil to mm". www.merusonline.com. MERUS GmbH.
  3. 1 2 "Corrosion Monitoring and Inspection – Is There a Difference?". www.jmcampbell.com. John M. Campbell & Co.
  4. ↑ "TECHNICAL NOTE AND GENERAL GUIDE FOR CORROSION COUPONS" (PDF). www.rcslgroup.com. BERKSHIRE, UNITED KINGDOM: ROSE CORROSION SERVICES LIMITED. Archived from the original (PDF) on 2021-02-04. Retrieved 2021-02-10.
  5. ↑ "Caproco Internal Corrosion Monitoring Specialists". www.caproco.com. 4815 Eleniak Road, Edmonton, Alberta,Canada.{{cite web}}: CS1 maint: location (link)
  6. ↑ "Products - Cosasco". www.cosasco.com. Santa Fe Springs, CA 90670 USA.{{cite web}}: CS1 maint: location (link)
  7. ↑ "HC Coupon Probes (Coupon Holders)". www.petroparda.com. December 19, 2016.
  8. ↑ "Retrieval Tool". www.alspi.com. Munford, AL 36268: Metal Samples Company.{{cite web}}: CS1 maint: location (link)
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.