The annual cost of metallic corrosion worldwide is staggering. Considering the cost of maintenance, prevention, replacement of parts and interruption of services due to maintenance, the World Corrosion Organization (New York, NY, US) says that the annual cost of corrosion worldwide is US$2.2 trillion, more than 3% of the world’s gross domestic product (GDP). The US Department of Defense has estimated the annual cost of corrosion in military applications alone at more than US$10 billion per year.
Corrosion-resistant composites are ideally suited to replace metal structures, including tanks, piping, cooling towers, railcars for chemical transport and much more, in this huge sector.
The most pressing need is still in the area of underground pipe. It’s been 45 years since Insituform (St. Louis, MO, US) founder Eric Wood invented cured-in-place pipe (CIPP). Since then, CIPP has continued to gain favor as municipalities recognize the huge benefits of an underground pipe rehabilitation technology that enables repair of deteriorating water/wastewater pipelines without expensive excavation (read more about cured-in-place pipe by clicking on the titles that reference it under "Editor's Picks," at top right).
The US Environmental Protection Agency’s (EPA, Washington, DC, US) report, titled State of Technology for Rehabilitation of Water Distribution Systems, says, “The impact that the lack of investment in potable water infrastructure will have on the performance of aging underground infrastructure over time is well documented and the needed funding estimates range as high as US$325 billion in the coming 20 years.”
The 18th Annual Underground Construction Municipal Sewer and Water Survey, conducted by Underground Construction magazine (Oildom Publishing Co., Houston, TX, US) reported in February 2015 that, for the first time in many years, municipal sewer and water personnel were somewhat optimistic about spending plans for 2015 and beyond. “Municipal authorities report spending plans for sewer/water/storm sewer piping systems of US$10.3 billion in new construction and US$7.8 billion for rehabilitation, an increase of 6.1% over actual 2014 spending.” Almost 52% of survey participants prefer to use trenchless methods in lieu of open-cut techniques for construction and rehab projects, and for those respondents, CIPP is, by far, the most preferred trenchless rehab method, cited by 52%.
A newly recognized threat, however, is that to undersea pipe. Global oil and gas interests operate more than 175,000 km of subsea carbon steel pipelines at varying depths around the world. These pipelines transport crude oil, gas and related products between offshore platforms and from offshore platforms to onshore facilities.
Counter-intuitively, one of the greatest threats to these undersea delivery systems is not saltwater, the external corrosive agent, but an unwelcome bacterial stowaway in crude oil that “breathes” the sulfates in crude and leaves behind highly corrosive hydrogen sulfide: “Due in large part to sulfate-reducing bacteria [SRB] accelerating internal corrosion, these pipelines can have a relatively short lifecycle,” says Robert Walters, global project director for Anticorrosion Protective Systems (APS, Dubai, UAE).
Together with PETRONAS Carigali Sdn Bhd (Kuala Lumpur, Malaysia), APS has developed in response an innovative composite liner system that places a corrosion-resistant barrier between an aggressive service medium, such as SRB, and the steel. Known as the InField Liner, or IFL, the liner also offers a secondary containment capability in the event of a rupture or damage to the outer steel pipeline and promises to dramatically extend the service life of the pipes, which have historically needed replacement in as few as four years. The liner was designed to be pulled through pipe lengths of up to 5 km with multiple 90° bends that have radii as small as 5D (D = nominal pipe outside diameter; 5D is a radius bend length that is five times the nominal pipe diameter). Each liner is custom designed and manufactured to match the original host pipeline bore, in nominal diameters from 152.5 mm to 457 mm. To install the liner, then, it must be flexible enough to be folded and temporarily bound so it can be pulled through the pipe and then inflated (see “Composites extend service of corrosion-prone oil and gas pipelines” under ”Editor’s Picks”).
Although IFL by APS is a distant cousin to CIPP, technologically, it is the first commercial composite liner for pipeline operators in the offshore market. Since its inception, CIPP in a variety of forms has created a substantial market for composite materials in the rehabilitation and repair, rather than replacement, of underground pipelines. IFL looks like an idea with equally great potential to create a similar rehab/repair market for undersea pipelines.