BILLINGS - This winter, the tallest thing on the Billings horizon won't be First Interstate Bank. It will be one of the world's largest cranes with a 500-foot boom swinging two large pieces of oil refinery equipment into place.
"It's a Mammoet PTC ringer crane, 1,600-metric-ton capacity," said Brady Hobza, project engineer for ConocoPhillips. "It's the fourth largest crane in the world."
It is a megacrane special ordered to install two, 350-ton coker drums that earlier this year eclipsed two-way traffic on Montana backroads while traveling less than 35 mph to Billings. The drums became known as "megaloads," built in Kobe, Japan, and shipped by sea, river and road to Billings.
The upcoming project to install the drums at ConocoPhillips refinery in Billings is no small matter.
Crews are hustling to prepare the drums for the crane's arrival. Shortly after the drums arrived in pieces, welders began slowly fusing their 2-inch thick steel walls. The tanks had to be stood upright on temporary stands made from steel girders and can be seen clearly from U.S. Interstate 90 east of the South 27th Street exit.
Scaffolding now completely encircles the 280-foot structures so that workers can cover them with insulation and metal siding.
If the to-do list consisted of only getting the new tanks in place, perhaps ConocoPhillips could unpack the Mammoet crane from the more than 100 semitrailers that will haul its pieces here in a couple months and get to work.
But the project is expected to take most of the spring of 2012 to complete. Before the new drums can be placed, there are two old coker drums to be removed.
Coker drums are a key part of the ConocoPhillips refinery that allows the company to extract gasoline, diesel and jet fuel from the heavy, sludge-like portion of the raw crude. The heaviest portion is called asphalt. Refiners pull the fuel and chemicals from the more liquid portions of the unrefined oil and then pump the asphalt into a furnace where it's heated to 900 degrees.
Once hot, the asphalt is pumped upward into the coker drum, where the jet fuel, diesel and gasoline vaporize and rise to the top, leaving the ever-thickening sludge behind.
With the vaporous fuels captured, roughly 90 percent of the fuel from the raw crude has been removed, said Steve Steach, the refinery manager. Without the extraction, only 70 percent of the fuel is captured from the crude.
After the vapors are collected, a giant drill with high-pressure water nozzles is lowered into the tank to blast the asphalt's crusty remains from the tank walls. The drill's nozzles spray 100,000 gallons a minute, at 3,200 pounds of pressure per square inch. The water is recycled for another wash.
The petroleum remains, which are washed out the tank's bottom, are known as petroleum coke. It's a crusty, coal-like substance that still contains the last bit of energy trapped in the raw crude.
That petroleum coke is sold to power plants, cement kilns, or other industrial customers who blend it with other fuels for burning to make energy.
ConocoPhillips has been extracting fuel from coke for a half century, Steach said, but only started to the process at its Billings refinery about 20 years ago. That's because in the beginning there were no obvious customers like ones found near coastal refineries.
"Refiners on the coast sold it to ships for bulk fuel," Steach said.
The coker drums in service for 20 years at the Billings refinery are tired, said Brian Taylor, the project's engineering supervisor. Rarely out of service, the drums repeatedly go from ambient temperature to 900 degrees and back down in a short time. That expansion is rough on the steel tank, which actually increases 6 to 8 inches in height when fully heated. Over time, the tank wears and cracks. Crews vigilantly search the tanks for signs of stress and weld cracked areas back together, but eventually the metal becomes too weak to continue.
Hobza said the Mammoet crane will pluck the top flights from the refinery's steel coker derrick, leaving the tops of the old tanks exposed. Then, the crane will pull the old tanks up through the top of the derrick and lay them on the ground, where a local salvage crew will spend weeks cutting the drums apart.
The new drums will then be hoisted above the derrick and lowered into place.
The refinery will be shut down for routine maintenance while the construction takes place. By then, spring will have arrived.
The new tanks should last 30 years, Taylor said, but engineers at the refinery will begin planning their next replacement about 10 years ahead of time.
Contact Tom Lutey at firstname.lastname@example.org or 657-1288.