Cathodic Protection Primer |
January 2011 |
Corrpro Helps Pipeline Owners
Save Money and Extend Asset Life
By Jayne Bringer
Corrpro has been a leader in the corrosion industry for over 25 years. Founded in 1984, a group of 11 corrosion protection professionals started Corrpro Companies to provide corrosion engineering services for a variety of applications.
When the company first started, it opened offices in Cleveland, Houston, Chicago and San Francisco — in the homes of four of its original founders.
Today, Corrpro has 35 professional engineers, 193 NACE International-certified personnel and 423 Operator Qualification (OQ) personnel in the United States, United Kingdom and Canada.
“My father and David Kroon got started working out of the basement of our family home in the early 1980s,” says Jeff Rog, the son of one of Corrpro’s original founders, Joe Rog. “Looking back at where they started and where Corrpro is today, they were responsible for creating a global organization in the corrosion industry.”
Today, David Kroon is President and Chief Engineer for Corrpro and Jeff Rog serves as a Vice President.
Over the years, Corrpro acquired 19 companies, broadened its product lines, increased its geographic reach and grew its customer base. Through Corrpro’s acquisitions, the company has a history solving corrosion problems dating back to the 1920s.
In 2009, Insituform Technologies Inc. acquired Corrpro and made it possible for the company to offer an even more comprehensive array of specialized pipeline protection products and services to its customers. Corrpro became a part of a growing family of Insituform companies offering pipeline protection to the energy and mining industry, municipalities and various agencies around the globe.
Much like its parent company Insituform, whose name describes a process of rehabilitating an existing pipeline from the inside using cured-in-place pipe, Corrpro’s main service offering — cathodic protection — may at first seem not only difficult to comprehend, but also pronounce. However, cathodic protection is based on simple electrical principles that can be easily explained. To understand what cathodic protection is and how it works, we must first understand the basic principles of corrosion.
What Is Corrosion?
The metals we use on a daily basis do not naturally appear in the form in which they are used. Instead, most metals are first mined as ores, then refined and often combined with other compounds.
To extract pure metal from ore, the raw product is subjected to extreme heat to remove impurities. This results in a refined product that has added energy to the metal. Nature won’t let this added energy stay in the metal forever. With exposure to electrolytes such as soil, water or concrete, any products made from ore will eventually revert back to their natural state. One example is steel, which reverts back to iron oxides — or rust.
How Does Cathodic Protection Work?
Cathodic protection can help maintain the added energy in refined metals, thus preventing the onset of corrosion.
Each different type of metal has its own unique “potential” ranking in the Galvanic Series of Metals. Metals with more negative potentials corrode first, as the release of energy coincides with the degradation of the metal into its natural state.
Thus, metals with higher negative potentials, including magnesium, zinc and aluminum, corrode easily upon exposure to the elements as they gradually lose energy.
|
Metals with lower energies include silver, gold and platinum. Because the energy levels in their refined states are lower, these metals do not corrode as readily.
A cathodic protection system uses this basic energy principle to prevent corrosion. By attaching a lower energy metal (cathode) to a higher energy metal (anode), Corrpro can prevent degradation of the “cathodic” metal. For instance, to prevent the corrosion of a steel pipe, you could connect it to a higher energy metal such as magnesium. The transfer of energy causes the magnesium anode to corrode first while preserving the steel pipe.
An electrical connection between the anode and cathode can be achieved using a wire, metal coupling, welding or direct physical contact. In large cathodic protection systems where a galvanic anode may not provide adequate protection, this connection is regulated using a transformer-rectifier. A rectifier converts AC power to a DC output, ensuring that there is enough current to provide complete corrosion protection to large assets.
Different Applications for Cathodic Protection
Water and energy pipelines are not the only assets that can benefit from cathodic protection. Cathodic protection systems are used for a variety of different materials and applications. Fuel tanks, water tanks, offshore structures, marine vessels and concrete structures with metal rebar can all be preserved using the process.
Corrpro Today
Corrpro has come a long way since its first pipeline project in North America in 1984 where the company performed buried gas pipeline testing for ExxonMobil. Since 1987, Corrpro has maintained a full-time working crew at the ExxonMobil Baytown Refinery in Texas, one of the world’s largest refining complexes. The company not only provides engineering design work, while operating and maintaining the corrosion protection systems throughout the large complex, but it has also received the highest ExxonMobil award for safe operations every year since 2000.
Corrpro continues to maintain its relationships with ExxonMobil and other clients such as TransCanada, El Paso Corp. and various branches of the U.S. Armed Forces. In 2010, Corrpro received work orders with a combined value of $5.3 million from TransCanada as part of three-year term contract for cathodic protection. The company also recently completed projects protecting steel wharfs in Alaska for the U.S. Coast Guard and designing cathodic protection systems for the U.S. Navy at military installations around the world.
Continuing its leadership in the cathodic protection industry, Corrpro recently applied for a patent for a “Green Rectifier” that provides cathodic protection in remote areas where access to a power source is unavailable. Using both solar and wind energy, the Green Rectifier is environmentally sustainable.
Choosing a Cathodic Protection System
|
Kroon described the benefits of a corrosion control program: “Corrosion control programs save pipeline operators money with benefit to cost ratios exceeding 8-to-1. The best approach is to have knowledgeable engineers develop a complete program for design, construction, monitoring and maintenance. Responsible companies will optimize systems while ensuring regulatory compliance, safe conditions and environmental protection.”
It is most effective to choose a solution that not only puts a system in place, but also has a plan to monitor performance over a period of time that is in line with a client’s needs. With proper design, the life of a cathodic protection system can be extended, thus saving you money and extending the life of pipelines and other assets.
Jayne Bringer is Senior Marketing Specialist for Insituform Technologies Inc., the parent company of Corrpro.
[Editor’s note: This article contains information from “Corrosion and Corrosion Control,” by David H. Kroon, P.E., and N. Dennis Burke, P.E.]