The Monitor

Production Process Insights

How corrosion coupon holders can save your assets

Posted by Kevin Kirst on 3/31/16 10:17 AM
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Metal corrosion is inevitable, and has the potential to cause catastrophic assets failure, which can injure operators, damage the environment, and lead to costly downtime.

The good news is that corrosion within a pipeline or vessel is easy to measure. A weighed sample – called a coupon – of the metal or alloy being measured is introduced into the system and then removed after a set time interval. The coupon then is cleaned of all corrosion residue and reweighed. The weight loss is converted to a corrosion rate (CR) or metal loss (ML) rate. This process can help identify where and why corrosion may have occurred, and what type and rate.

Coupons are an effective way to gauge internal corrosion rates of pipelines, processing equipment and storage vessels. This method of corrosion measurement simply requires an appropriate type of coupon, a corrosion coupon holder, and a reliable means of removing the corrosion residue without disrupting the metal substrate.

Save time, money, with monitoring

The best corrosion coupon holders are easily insertable and retractable under pressure to allow systems to be monitored while under normal operating conditions. The coupon is removed safely without venting or draining of the process product, so there is no system downtime. Data from corrosion monitoring helps:

  • Determine whether equipment needs maintenance or replacement, before it’s too late
  • Prevent catastrophic leaks and system failures
  • Extend equipment and asset life
  • Preserve system uptime and save money

The right tools aid in best practices for corrosion monitoring and ensure systems can continue to operate at optimal capacity. Corrosion coupon holders generally can accommodate flat rectangular, electromagnetic, rod, disk or flush style coupons. Plus, a sample probe, quill or drip pot assembly can be incorporated to collect samples of the process product at the same point where the coupon is staged.

Traditional corrosion monitoring equipment requires a three-person service team using a specialized tool to retrieve and install corrosion coupons, with the tool weighing more than 150 lbs. including the service valve, and often requiring use of a jib crane for safety. Retrieving this type of corrosion monitoring tool from high-pressure lines is dangerous, laborious and expensive, especially in areas with space limitations, such as offshore oil rigs.

However, there is a better way.

The best in corrosion monitoring

Sentry® corrosion coupon holders are strong and durable, but lightweight. They make insertion and retraction under pressure safe, easy, quick and cost-effective. Only one insertion tool is needed for multiple systems, and that the tools can be operated easily by only one person. These corrosion monitoring and chemical injection tools are designed for either low- or high-pressure systems – even extreme high-pressure applications of up to 10,000 psi (689 bar) MAOP at 100°F (37.7°C). To meet any application need, they can be hand-insertable or mechanically insertable.

Mechanically inserted corrosion coupon holders used in high pressure systems from about 500 to 5,000 psi require insertion tools to easily place them into and remove them from the system without interruption of the process. Our insertion tools have a side handle crank so the operator is able to work from a stable and secure position to the side of the tool, with no heavy service valve required. Plus, they can be operated from any position, including upside-down, for applications with difficult to access spaces, and are non-telescoping to reduce the space needed for operation.

To save on time and manpower, certain tool models are designed to be left in place in the pressurized system. The Saf-T-Vise™ patented locking collet safely secures the tool within a process stream until it is released by the operator. And, longer travel lengths of up to 25 feet for the tool holders mean that a corrosion coupon can be placed at just the right place in the process for the most effectiveness.

Because only one tool is needed for multiple systems, and the tools can be operated easily by only one person, customers save significantly on both tools and manpower without sacrificing quality, efficiency or safety.

Learn more about our corrosion monitoring and chemical injection product portfolio.

Sentry's Industrial Representative Sampling eBook

Topics: Upstream & Midstream

Written by Kevin Kirst

As industry manager for the refinery market, Kevin employs his 25-plus years of experience in engineering, application support and sales to develop new ways to sample, monitor and measure customers’ processes, with a primary focus on the crude oil refining industry. Like all our company employee-owners, Kevin is committed to developing technologies and equipment that allow customers to operate their processes at optimal efficiency while maintaining high levels of safety and product quality.

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