Rusty Oil & Gas Pipelines Could Drive Molybdenum Price Higher, Part One
As long as air conditioners keep us cool in the summer and central heating warms us in the winter, all is well in the world. In order to keep this gas and electricity continuously flowing into our homes, molybdenum has emerged as an essential metal to help preserve challenging energy transportation network. The anti-corrosive qualities found in molybdenum could also help prevent the collapse of the U.S. energy infrastructure.
Tucked beneath our streets, farms, deserts and forests lays a multi-million mile network of mostly aging pipelines supplying our energy needs. Meanwhile, hydrogen sulphide, carbon dioxide and common oxygen corrode the energy transportation system we rely upon to fuel our cars and power our computers. Corrosion annually costs the U.S. economy about $276 billion, more than three percent of the GDP, according to Technology Today (Spring 2005).
Unacceptably high percentages of two key energy-providing vehicles, such as nuclear power plants and the U.S. pipeline network, have begun aging beyond their original design life. About half of the nation’s 2.4 million miles of oil and gas pipelines were built in the 1950s and 1960s. And the composition of the liquids flowing through those pipelines has deteriorated over the past half century.
According the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA) website, “Corrosion is one of the most prevalent causes of pipeline spills or failures. For the period 2002 through 2003, incidents attributable to corrosion have represented 25 percent of the incidents reported to the Office of Pipeline Safety for both Natural Gas Transmission Pipelines and Hazardous Liquid Transmission Pipelines.” Industry sources note corrosion is also a leading cause of pipeline leaks and ruptures.
Corroded Prudhoe Bay Pipeline Rupture
Corrosion makes each of us vulnerable to price shocks. On August 7th, public awareness about the impact of corroded pipelines in the energy infrastructure registered when prices shot up at the gasoline pump. BP shut down about eight percent of U.S. oil production. The international oil company cited ‘unexpectedly severe corrosion’ in its Alaska oil pipelines. This was the first shutdown ever in America’s biggest oil fields. According to BP, sixteen anomalies were discovered in twelve separate locations on the eastern side of the oil field. Earlier in the year, a pipeline spill was reported from the western side of the field.
Immediately following the corroded pipeline rupture, the industry introduced legislation, hoping to prevent a recurrence. Signed into law in December, the Pipeline, Inspection, Protection and Enforcement and Safety Act, affected low-stress crude oil pipelines, and included provisions for the improved controls and detection of pipeline corrosion. During Senate committee hearings, trade representatives pointed to the Department of Transportation’s Integrity Management program, implemented in 2001 and which was reported to have demonstrated a reduction of leaks and releases resulting from corrosion from high-stress inter-state gas pipelines in ‘high consequence areas.’
Official statistics published by the PHMSA Office of Pipeline Safety disagree. In the twenty-year period of 1986 to 2006, 2883 incidents resulting in 1467 injuries, 349 fatalities and nearly $860 million of property damage were reported by distribution operators at U.S. natural gas pipelines. In the five-year period ending in 2006, 25 percent of the incidents, about 20 percent of the fatalities, nearly 19 percent of the injuries and more than 69 percent of the property damage occurred compared to the previous fifteen years, before legislation was enacted. Similar percentages were reported by natural gas transmission operators.
Faced with aging, out-dated infrastructure, the pipeline industry aimed legislation toward the lowest-cost solution – detection of corrosion and piecemeal pipeline replacement – rather than addressing the separate issues which led to the problem.
Older Pipeline Steels Vulnerable to Corrosion
During its massive build up phase, U.S. pipeline infrastructure relied upon carbon and low-alloy steels for natural gas and petroleum transportation. As oil fields have aged, the risk of pipeline corrosion and pitting has increased. The Prudhoe Bay oilfield now produces more water than oil. This is a common occurrence in numerous U.S. oil fields and around the globe.
In the absence of water, hydrogen sulphide is non-corrosive to pipelines. However, increased moisture in pipelines is problematic, because it activates the corrosive capabilities of hydrogen sulphide. A combination of tensile stress, susceptibility of low-alloy steels and chemical corrosion will lead to sulfide stress cracking. Hydrogen ions weaken the steel. Over time, pressure causes the embrittled steel in the pipeline to rupture.
Similar problems have emerged in the natural gas sector. As deeper wells are drilled in hot, high-pressure gas deposits, the probability of hydrogen sulphide in gas can increase. An entire industry has sprung up around decontaminating sour gas. U.S. sulfur production from gas processing plants accounts for about 15 percent of the total U.S. production of sulfur.
Sour gas is a naturally occurring gas containing more than one per cent hydrogen sulphide (H2S) and sometimes above 25 percent. It is typically identifiable by a strong ‘rotten eggs’ smell. Commonly found in the foothills of western Canada’s Rocky Mountain region, sour gas comprises more than one-third of the gas produced in Alberta. It is ‘sweetened’ at more than 200 plants in this province to bring the gas up to pipeline quality.
The one-to-two percent of the H2S remaining in the gas is considered pipeline quality. But the interaction of the hydrogen sulphide with water can accelerate the pipeline corrosion process. Potentially, the combination of the old gas pipeline material and the rise of sour gas could pose the greatest risk to gas pipeline safety. Molybdenum is crucial in defending against hydrogen sulfide environments as reported in a metallurgical journal study and published by the Defense Technical Information Center.
High Strength Low Alloy Steels
Long running cracks, some stretching more than six miles, first began fracturing gas pipelines in the 1960s. The industry’s solution was the development of, and encouragement to use, High Strength Low Alloy (HSLA) steels. Older pipelines, built in the 1920s (or earlier), of 500mm or less, could only handle an operating pressure of about 20 bar. Annual capacity of gas transportation long those pipelines stood at about 650 million or less. Because of today’s high energy content of compressed gas at 80 to 100 bar and an annual transportation capacity of 26,000 million or more, pipelines require modern HSLA steel to prevent them brittle fracture behavior or ductile cracks.
HSLA steels capable of building large diameter pipes came about from the introduction of the thermomechanical rolling process in the 1970s, which maximized grain refinement. By increasing the strength of the steels, one could sustain the high operating pressure and reduce the wall thickness of the pipe. Steel manufacturers could use less steel, reduce the pipe weight and double the yield strength. Transportation costs from plate and pipe mills to construction sites were also reduced. Delivering a lighter-weight pipe to remote or arctic areas became more economical.
Steel is vulnerable to acids and is generally stable with pH values above 7. Acidity-causing corrosion comes about when magnesium and calcium are hydrolytically converted to form hydrochloric acid. Hydrogen sulphide and carbon dioxide are also acid-forming gases corroding steel. Molybdenum’s corrosive-resistant properties served beyond its original scope in manufacturing modern steel.
Initially, molybdenum was included to harden steel and increase weldability, while reducing the carbon content previously utilized. Higher toughness, but lower tensile strength, was required. By adding molybdenum in the range of 0.15 to 0.30 percent, depending upon the pipe wall’s thickness, carbon content in the steel could be reduced to 0.07 percent. The metal has played a key factor in oil and gas development projects as pipes continue being used in arctic, sour and sub-sea environments. Apparently, the more rugged the climate, the better the more recent gas projects have panned out. One example would be the Sakhalin oil and gas project in Russia’s Far East, where on- and off-shore pipelines in excess of 1,000 miles would transport some of the world’s largest natural gas reserves.
Steels for natural gas pipelines require higher standards than those used for oil. These pipelines must carry compressed gas at minus 25 degrees centigrade to minus 4 degrees centigrade. Crack growth and brittleness intensify in the severe arctic environment. Achieving low-temperature notch toughness, grain size control, and low sulfur content were some of the problems solved while developing this modern steel.
Since the 1970s, more than two million tons of molybdenum-containing HSLA steels for pipelines were manufactured. We checked with the world’s largest pipeline manufacturer Tenaris (NYSE: TS), which offers steel with high resistance to Sulphide Stress Corrosion Cracking (SSCC), to confirm continued interest in molybdenum. In a phone call to the company’s Houston office, we discovered the company had purchased $65 million of ferromolybdenum in the six-month period ending January 31, 2007 for use in its new pipeline steels. As an aside, the company representative, having checked with company’s central purchasing ‘sister company’ in Argentina, pointed to the rising cost of ferromolybdenum and anticipated paying $80 kg in the coming year. (This could help explain why the moly price has remained high through 2006 and could rise higher in 2007.)
Pipeline Projects on the Horizon Confirm Moly Demand
We talked with Rita Tubbs, managing editor of Pipeline and Gas Journal (P&GJ), about molybdenum content to be used in the construction of gas pipelines outside of the United States. “Most will adhere to the standards used in North America,” she told us. According to Adanac Molybdenum Corp consultant, Ken Reser, the new standard has grown to 0.5 percent moly content.
In a December 2006 worldwide pipeline construction survey, compiled by Rita Tubbs, she observed “81,593 miles of new and planned oil and gas pipelines under construction and planned.” She pointed out North American pipeline construction plans nearly doubled to 28,314 miles. In these figures, Tubbs spotlighted Canadian activity, which is expected to increase overall North American pipeline construction mileage. She wrote, “By 2008, contractors expect to see a workload that has not been seen in Canada for nearly three decades.”
Tubbs explained in her report, “Much of the activity will be generated by the massive oil production that will come from the oil sands in northern Alberta which contain the largest deposits of hydrocarbons on earth. Terasen and Enbridge plan to move oil sands by pipeline.” Molybdenum is likely to play a vital role in pipelines carrying the material, which is a mixture of sand bitumen and water – with high sulphur content.
An unexpected addition to the P&GJ report came on Oil Gas ELECTRICAL Consultants 26th. Shanghai Daily newspaper reported a boom for China’s energy pipelines. The world’s most populous country plans to add another 15,000 miles of oil and gas pipelines to its existing infrastructure of 24,000 miles by 2010. In three years, the country hopes to extend its mileage by nearly 63 percent as China races to raise its energy mix for gas to 10 percent.
Perhaps the greatest number of new pipeline growth will occur in the United States – the world’s largest energy consumer. By 2025 EIA expects the US will need 47 percent more oil and 54 percent more natural gas. To transport this energy, transmission and distribution line mileage is expect to increase by approximately 30 percent. This implies pipeline projects on the order of some 600,000 miles.
Whether this would include the nearly one million pipeline miles sorely in need of replacement since the introduction of molybdenum in the 1970s to the steel in pipes is not known. However, whether one calculates the number of new pipeline miles potentially constructed or the number of replacement pipeline miles, one arrives at a staggering quantity of molybdenum required to more strongly protect the steel from future corrosion.