You Tell Us: Electron Beams Zap Oil to Pump More Petrol

Will refineries turn to radiation, or is cold cracking just crackers?

3 min read

Samuel K. Moore is IEEE Spectrum’s semiconductor editor.

At the last minute, a line was inserted in the 2006 U.S. energy bill instructing the secretary of the Department of Energy to spend US $250 000 to study an experimental technology called cold cracking. Don’t know what that is? Neither did the Texas congressman who inserted the line. But that’s politics.

”We’ve got a great system,” says Bud Brainerd, whose Alabama congressman had convinced the Texan to insert the line. Brainerd’s the president of PetroBeam, in Opelika, Ala., the only U.S. company conducting research into the technology.

Cold cracking uses beams of high-energy electrons to transform the thick parts of crude oil into oils, gasoline, and other petroleum products thin enough to pump through a pipeline. The question is whether a conservative, capital-intensive oil industry will buy the idea. To hear Brainerd tell it, refining could certainly use something like it. A lot of new oil fields have oil that’s too thick to pump, and that’s a shame, because there’s so much of the stuff. There are an estimated 2.5 trillion barrels of ultrathick oil locked up in the sands of Alberta, Canada, alone.

Oil producers now must thin these deposits in one of two ways. They can mix in an already refined product containing kerosene, or they can subject the thick oil to intense heat and pressure, which breaks some chemical bonds, making it less viscous. Neither option comes cheap. Brainerd believes his company’s approach could do the job for less by cracking the heavy oil with standard industrial irradiation equipment at room temperature and atmospheric pressure.

The trouble is that radiation usually makes things worse. Most of the molecules in oil are long chains of hydrocarbons. Generally, the longer the chain, the higher the viscosity and the less valuable the oil. Hitting such a chain with a high-speed electron sometimes breaks it in two, but much more often bonds it to its neighbor in a process called cross-linking. When that happens, an already slow-flowing soup of noodlelike molecules is transformed into a stagnant mesh of interconnected chains.

”That’s just the opposite way you’re trying to go in cracking technologies,” says Walter Chappas, a nuclear engineer and cofounder of PetroBeam. In fact, electron-beam cross-linking is deliberately done to manufacture plastic shrink-wrapping for packaged meats and to toughen tires. Both applications employ irradiation machines that resemble gargantuan, 200-kilowatt television tubes.

Researchers, particularly in countries of the former Soviet Union, have been trying to get radiation to break more molecules than it binds, but for a long time they succeeded only by using an uneconomical amount of heat and pressure. Then, in the spring of 2005, Chappas’s co-workers from Kazakhstan finally got electrons to crack oil under normal conditions. ”What we now have is a process that is quick, reliable, robust—in that it processes a wide variety of feedstocks—and we can do it very economically,” says Brainerd. He won’t reveal the secret, except to say that it requires no adjustments to the irradiation equipment.

Besides thinning Canada’s tar sands for transport, the process could be used at oil refineries to turn heavy fuel oils, used by railroads and ships, into much more valuable gasoline and diesel. That’s currently done in high-pressure reactors called catalytic crackers, which operate at more than 650 °C. There are more than 300 of these reactors currently operating at refineries around the world. Brainerd says a full-scale cold-cracking unit could crack 10 thousand barrels of oil a day—typical of what’s wanted in oil fields.

Right now, however, Chappas and Brainerd are limited to testing small amounts of oil using electron guns borrowed from plastics manufacturers. They are in talks with refiners on partnerships to demonstrate the technology and have raised enough money to build a 1000-barrel-per-day pilot plant. The plant will help work out any bugs found in scaling up the technology and will help PetroBeam prove to risk-averse refiners that the process is in fact inexpensive.

According to Calvin Cobb, a refining industry consultant in Houston, PetroBeam will succeed only if it can cut the cracking cost by about two-thirds. ”Nobody’s going to tear down a catalytic cracking unit and replace it with something that’s just a little bit better,” he says.

As for PetroBeam’s $250 000, the energy program under which it fell was axed, and the money was never appropriated. That, too, is politics.

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