A Cure for Coatings |
July 2010 |
Adapted Technology Offers Pipelines Added Corrosion and Mechanical Protection
By Bob Buchanan and Ryan Schwarz
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Sometimes a proven technology that has been around for a while will find a new niche application in areas that were not originally considered. Take for example an emergency leak repair product that was invented for the marine industry and is now required by the U.S. Department of Defense. It is no surprise that this technology has transitioned into new composite systems to meet the individual needs of specific industries such as municipalities, industrial, mining, refineries and now oil and gas.
Dr. Richard Lazzara, the original inventor, patent holder and founder of Neptune Research Inc. (NRI), has enjoyed the successes of his unique pre-impregnated, moisture-cured composite over the last 28 years.
As often is the case, great ideas have difficulty becoming commercially successful simply because of availability of complementary technologies or access to markets and decision-makers. Enter into the picture a partner with these tools and something good is bound to happen.
Canusa-CPS is a manufacturer of field-applied pipeline corrosion protection products and has steadily been developing new products and improving existing technologies for more than 35 years. As a pioneer in heat-shrinkable coatings, Canusa has branched out into pipeline coating adhesives, liquid applied epoxies and, more recently, visco-elastic coatings, which are based on adhesives developed in the 1980s but finding new applications today. With its product range, years of experience and global network, Canusa is a natural fit to collaborate with a company such as NRI.
The technology that NRI developed has established the company as a leading manufacturer of reliable, high-performance, pre-impregnated composites, the success of which is credited to the ease of product application provided by the moisture-curable polyurethane resin delivery system. NRI is now expanding this technology within the corrosion coating sector of the oil and gas industry by developing a variety of solutions for different pipeline applications. Specifically of interest, using the composite as a protective external jacket over the primary corrosion coating for higher impact strength and abrasion performance, especially in horizontal directional drilling processes.
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This niche application has recently resulted in Canusa and NRI teaming up to commercialize a field-applied system for protecting pipeline field joints or pipe sections during horizontal directional drilling or for severe soil stress conditions. Interestingly, the concept was patented by Canusa-CPS a number of years ago and the company enjoyed some success using UV-curable fiberglass systems, but the process was cumbersome and had some shelf life drawbacks that slowed its development. By partnering with NRI and its variety of moisture-curable composites, the concept has become much more viable. This brings two companies together that have the desire to develop product solutions that truly add value to the pipeline industry.
The primary system that has been developed incorporates a soft, visco-elastic adhesive-based coating manufactured by Canusa with a hard, pre-impregnated fiberglass protective layer manufactured by NRI.
Corrosion Protection
The visco-elastic product is relatively soft and very tacky, resulting in excellent corrosion protection properties.
The advantages are that the product requires very little pipe surface preparation, few tools for installation and can be installed very quickly. Because of its softness however, on its own it has low soil stress resistance and certainly would be abraded during directional drilling.
Mechanical Protection
By adding a protective layer such as the fiberglass pre-impregnated outer wraps, the entire system has excellent corrosion protective properties along with extremely high resistance to abrasion, impact and indentation.
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Also, because the outer wrap is moisture cured, the working time and cure speed can be easily managed. In the field, the user can keep the material cool to slow the cure or warm to speed up the cure, using cold or hot water. Cure time can also be adjusted by the manufacturer to accommodate specified project parameters. In marine environments or freezing temperatures, salt water may be used.
System Approach
On a recent test project, the client quickly saw the benefits of the system. With few tools and some rolls of material in pre-packaged kits, the directional drilling contractor was able to install the system in less than 10 minutes and pull the pipe through the bore in less than one hour. This is contrary to epoxy-based systems, which can take up to 24 hours to cure and, if holidays in the coating are found, then recoating may be required.
Testimonial
After his first project, the construction manager from a prominent gas distribution company wrote in an e-mail to NRI and Canusa, “We have already ordered our 12-in. pipe for our next project.
We have a 10-in. project approved and in motion. It would be nice to have a reference price for this material for us while we are estimating these jobs. Yesterday we pulled in the section of 8-in. with your product on the weld joints and we are very pleased with the ease of installation and the durability. I believe this will be our primary product for us to use on bore pipe from now on.”
Pre-Packaged Kits
As mentioned, the system is supplied in kit form that is sized for the pipe diameter and client specified cutback width.
Included in the kit are a roll of the corrosion protection coating and a roll of the fiberglass outer wrap in a heat-sealed foil pouch. In addition, installer kits are supplied separately and include gloves and a compression film. By kitting the system in this manner, the overall cost per joint is tightly managed to make it economically viable.
After basic surface preparation and cleaning, the system is installed in three simple steps.
- The visco-elastic corrosion coating is wrapped around the pipe over the steel cutback including an overlap onto the mainline coating.
- The fiberglass outer wrap is then wetted and spiral wrapped over the specified coverage width, ensuring that a minimum spiral overlap is maintained.
- A compression film is wrapped and perforated to consolidate the system and allow curing to take place.
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The use of alternate corrosion coatings combined with different types of composites laminates are being considered for similar corrosion protection applications. For example, the fast cure profile of the outer composite wrap can be used to speed up the time to backfill for traditional two component epoxy coatings just by encapsulating the slow curing epoxy coating with a fast curing outer composite layer. The option is also available for the pipeline owner to use a variety of mainline coatings, including epoxies, heat-shrink sleeves, tapes and visco-elastic coatings, with the peace of mind of an exterior protective layer. Each of these applications is covered under the aforementioned Canusa patent and provides the flexibility for a “build your own system” based on the performance requirements and budget for each specific project. This versatility results in a variety of cost-effective systems that provide long-term corrosion protection using a broad range of industry trusted corrosion coating systems with the added benefit of increased mechanical protection to the pipeline.
As with many new concepts, you might ask, “Why didn’t somebody think of this before?” In many cases somebody did but it takes the right combination of products, companies and people to make the idea work to its fullest.
Bob Buchanan is global marketing manager for Canusa-CPS, in The Woodlands, Texas, (281) 367-8866 (www.canusa.com). Ryan Schwarz is vice president of sales and marketing for Neptune Research Inc. (NRI), in Lake Park, Fla., (561) 683-6992 (www.neptuneresearch.com).
Avoiding Stress Corrosion Cracking
Q & A with Phil Korosec on a Breakthrough in Distributing Fuel Ethanol via Existing Pipelines
By NAP staff
North America has a nearly 100,000-mile petroleum liquids pipeline network that currently provides a reliable, safe, efficient and economical delivery system for petroleum products, such as gasoline, diesel fuel, home heating oil and more. The U.S. government has mandated the increased use of fuel ethanol over the next decade, but currently that liquid is transported by costly trucking and rail. People are asking, “What if the same pipeline system could carry fuel ethanol, also reliably, safely, efficiently and economically?”
North American Oil & Gas Pipelines spoke with Phil Korosec, technical director at MidContinental Chemical Co. Inc., and asked him a few questions about a breakthrough in dealing with stress corrosion cracking (SCC), the hurdle that must be overcome in order for fuel ethanol to be distributed in existing pipelines.
NAP: Tell us, just what is “stress corrosion cracking”?
Korosec: The formal definition of stress corrosion cracking is the formation of brittle cracks in a normally sound
material caused by interactions of tensile stress, corrosive environment and susceptible materials. It is a well-known phenomena occurring in oil well drilling equipment, well completion situations and in industrial boilers. In regard to the nation’s petroleum-related pipelines, stress corrosion cracking is the tendency for the alcohol in fuel ethanol and other factors to lead to the slow growth of cracks along a pipeline.
NAP: Is there evidence of stress corrosion cracking related to fuel ethanol distribution?
Korosec: According to the 2003 API research report, API TR 939-D, stress corrosion cracking of steel in contact with fuel ethanol has been observed in user terminals, specifically storage tanks and loading/unloading racks prior to blending. SCC has not been observed in storage tanks used by ethanol producers or in equipment after blending ethanol with fuel. In order for companies to know whether internal SCC could be expected in their pipelines, researchers have been studying the environments that will support SCC, metallurgical factors that affect susceptibility to ethanol SCC, stress conditions that will promote crack initiation and growth, and the effectiveness of remedial measures.
NAP: Why is there such an emphasis on distributing fuel ethanol through existing pipelines?
Korosec: The emphasis is due to the increasing usage of fuel ethanol in transportation fuel that is mandated by the U.S. Environmental Protection Agency and RFS-2. The EPA called for 13 billion gallons of fuel ethanol usage in 2010, and increases that to 31 billion for 2022. Since most ethanol is currently transported by rather costly truck and rail, the industry would welcome the use of the less expensive pipeline transportation system.
It’s estimated that transporting fuel ethanol in existing pipelines instead of by truck or rail can reduce transportation costs by up to 90 percent in some areas. Resolving the stress corrosion cracking issue in pipelines can be an important factor in increasing transportation efficiencies and meeting EPA mandates.
NAP: What is the breakthrough in stress corrosion cracking that MidContinental Chemical has produced?
Korosec: Our company has a patent pending on new additive chemistries that are designed specifically to combat stress corrosion cracking while not compromising the quality or performance of the fuel ethanol. These additive chemistries consist of clear, non-hazardous, mobile liquids that work by coating the metal surface and neutralizing the effect of trace components in the fuel ethanol. Bench testing using ASTM G129 and other extensive tests on fuel ethanol under simulated, stress conditions indicate that fissuring and cracking can actually be halted, keeping harmful components of fuel ethanol from compromising the integrity of pipelines, tanks and other metallurgy the fuel might be exposed.
The additive has also been registered with the EPA.
NAP: If an organization is interested in distributing fuel ethanol through their pipelines, what steps should they take?
Korosec: Since our new additive chemistries are a custom-engineered chemical solution, we work with each customer on an individual basis. It’s critical to develop a solution customized to the situation, such as climate, pipeline or tank types and conditions, product flows and more. We are ready to help customers that are serious about the great opportunity presented by MidContinental Chemical’s new SCC additive solutions.
For more information about MidContinental Chemical Co. Inc. or its stress corrosion cracking additive, contact Everett Osgood at (913) 390-5556 or everetto@mcchemical.com.