The markets: Utility infrastructure (2020)
Corroded metal infrastructure continues to be a problem, and composite materials, including new advancements in graphene nanotubes, are providing solutions.
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Mitaş Composites can filament wind composite lighting poles up to 12 meters long and 800 millimeters in diameter. Source | Mitaş Composites
According to the American Iron and Steel Institute, there are about 185 million utility distribution poles in North America, and an estimated 2.5 million wood poles are replaced annually. These poles support power and telecommunications lines. Wood poles are commonly replaced due to age, damage and decay. Fiber-reinforced polymer (FRP) composite poles were developed in the 1960s to address these shortcomings, first installed in Hawaii as a solution to wood pole degradation and steel pole corrosion. Composite poles are more environmentally friendly because they don’t require the use of toxic chemical preservatives like creosote, pentachlorophenol or copper compounds. This chemical treatment also makes disposal of used wood poles very expensive. Although steel poles offer 60-80 years of service compared to 40-50 years for wood, as well as lighter weight, higher stiffness and lower maintenance, they also must be galvanized or coated to prevent corrosion and are also conductive, difficult to repair and harder to drill in the field for climbing access and installation. Composite utility poles offer the longest life, lowest maintenance, lightest weight and ability to drill for ease of installation.
Composite poles currently account for less than 1% of the overall utility pole market according to Lucintel (Dallas, Texas, U.S.), but their share is expected to grow from $228 million in 2018 at an annual rate of 5.7% to reach $318 million in 2024. Power transmission and distribution currently accounts for approximately 71% of the global composite pole market, but lighting, which comprises 23%, is likely to experience a relatively higher growth rate, fueled by the replacement of traditional materials.
In 2019, BASF Co. Ltd. (Shanghai, China) announced that its Boldur utility poles, produced via filament winding with the company’s Elastolit polyurethane (PU) and continuous glass fiber, are now available and are being used by a utility pole distributor in Japan. The ultra-light poles are said to withstand severe weather conditions and maintain reliable electricity supply in areas affected by natural disasters.
Mitaş Group (Ankara, Turkey), a manufacturer of steel towers, distribution and transmission poles, and substation structures for the energy market, has invested in a filament winding production line for manufacture of composite utility poles. The automation-ready equipment, with a manufacturing capability of 1,000 poles per month, makes Mitaş one of Turkey’s first manufacturers of composite utility poles and is enabling the group to grow and diversify its existing product range.
Composites’ superior strength are also fueling their growth in transmission cables. Aluminum conductor composite core (ACCC) cable for power transmission lines is produced by CTC Global (Irvine, Calif., U.S.). Compared to traditional aluminum conductor steel-reinforced (ACSR) cables, ACCC cables feature a carbon fiber composite rod pultruded with a thin sheath of insulating glass fiber composite to prevent galvanic corrosion with the aluminum overwrap. ACCC cable’s strength to weight ratio is roughly six times better than steel, with a coefficient of thermal expansion about ten times lower. ACCC cable also reduces power losses by 25-40%. With traditional cables, up to 25% of power is lost simply from transmitting electricity over long distances.
Similarly, Celanese Corp. (Dallas, Texas, U.S.) and Southwire Co. LLC (Carrollton, Ga., U.S.), North America’s largest wire and cable producer, co-developed the C7 Overhead Conductor, featuring a lightweight and high strength-to-weight, multi-element composite core of Celstran continuous fiber-reinforced thermoplastic rods (CFR-TPR), made by Celanese. The C7 Overhead Conductor reportedly not only increases capacity, but provides cost-avoidance benefits by obviating the need for new towers and poles, a need that would have to be met if increases were attempted with traditional steel-cored conductor cables. It also nearly doubles the transmission capacity, yet exhibits less sag than an aluminum conductor steel-reinforced (ACSR) cable of the same diameter.
In addition, composites can play an important role in refurbishing America’s aging underground potable water infrastructure by providing corrosion-resistant, durable and long-lasting underground pipe solutions. One example of composites put to use for piping was a water project in the Middle East. The selected pipe for the project was Amiantit Europe’s (Mochau, Germany) pipe product, Flowtite Grey, which was intended for water, sewage, waste and raw material management.
The 22nd Annual Underground Construction Municipal Sewer and Water Survey, conducted by Underground Construction magazine (Oildom Publishing Co., Houston, Texas, U.S.) and published in February 2019, indicates the strongest industry projections in many years, with every category showing growth. New installation of sewer infrastructure is projected to increase by 3.7% in 2019 to $5.4 billion, with a 3.9% increase ($3.85 billion) for water construction. Rehabilitation continues to outpace new construction with sewer rehab projected at 4.1% growth or $4.9 billion in 2019, and water growing 4.5% to $2.2 billion. Projected spending plans for U.S. sewer, water and stormwater piping infrastructure total $19.75 billion for 2019, representing an overall increase of 3.7%.
This survey also measured impacts from trenchless construction and rehabilitation methods, in which composite materials are used to reline existing pipes (cured in-place pipe, or CIPP). During budget-crunching times, trenchless rehabilitation gained ground as a cost-effective and successful stop-gap measure to stretch dollars. As a result, trenchless work has gained a foothold in all aspects of construction and rehabilitation in the US and abroad. The survey revealed that 52% of cities prefer to use trenchless CIPP for rehab, and for new construction, trenchless is used in about 25% of projects.
In 2018, the Innovative Materials for America’s Growth and Infrastructure Newly Expanded (IMAGINE) Act was introduced as a bill to the U.S. Congress, designed to promote the increased use of innovative materials, such as composites, in infrastructure projects.
In the meantime, filament wound fiberglass/polyester composites have found broad application in several stages of seawater reverse osmosis (SWRO) desalination. SWRO plants around the world use many miles of corrosion-resistant fiberglass-reinforced polymer (FRP) low-pressure piping as a distribution network, primarily over land, to carry seawater to the plant, to distribute the potable water that is produced, to carry the brine (salt and impurities) back to the ocean, and for internal plant treatment piping and energy-recovery devices. Fiber-reinforced plastic also forms storage tanks and piping used in desalination plants to contain sodium hypochlorite (NaOCl) used in chlorination of desalination process water, and for sulfuric acid — very difficult to store in metal but readily handled in fiberglass/epoxy vinyl ester tanks and piping at ambient temperatures and concentrations below 50%, according to corrosion industry resin producer Ashland.
TUBALL graphene nanotubes, a type of single-wall carbon nanotubes (SWNTs) developed by OCSiAl (Leudelange, Luxembourg and Columbus, Ohio, U.S.), can provide ESD protection by dissipating electrostatic charge inside and outside FRP storage tanks like these, preventing the possibility of static-related explosions. Source | OCSiAl
Using fiberglass tanks to fight corrosion, however, introduces the possibility of an electrostatic charge being generated when filling or emptying tanks, particularly those containing petroleum-based liquids, because the product movement can create a static charge between the liquid and the tank wall. To address this risk, fiberglass tank manufacturers have historically used anti-static fillers in the resin, typically carbon black or conductive mica, to dissipate any static charge. But, filler ratios up to 30% are often necessary, which makes wetout of the fiberglass more difficult and slows the resin cure rate. Use of TUBALL graphene single-wall carbon nanotubes supplied by OCSiAl (Leudelange, Luxembourg and Columbus, Ohio, U.S.) can provide electrostatic discharge (ESD) protection by dissipating electrostatic charge inside and outside a storage tank.
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