According to tests conducted on a stretch of the controversial Keystone oil pipeline which runs between the United States from Canada, electric fields could help improve oil flow, an advance that could save major amounts of energy during pumping.
Reducing the viscosity of crude oil helps it flow better, cutting down the amount of energy needed to pump it. Oil is usually heated in pipelines to decrease its viscosity, but this requires a lot of energy and counter-productively drives up turbulence in the oil, which makes pumping more difficult.
One potential solution emerged in 2006, when physicist Rongjia Tao at Temple University in Pennsylvania and his colleagues suggested that applying electric fields to flowing oil could simultaneously reduce viscosity and suppress turbulence in pipelines. (In similar work in 2011, these researchers showed that magnetic fields can reduce blood viscosity by 20 to 30 percent, which they suggested could help treat heart disease.)
To see how well electric fields might improve oil flow, Tao and his colleagues collaborated with Santa Barbara, Calif.-based energy company Save The World Air, Inc., to develop a device. Recent trials of the invention on oil pipelines in Wyoming and China showed that electric fields made crude oil particles form short chains. While these chains reduced viscosity in the direction of oil flow, they also increased viscosity perpendicular to oil flow, which helped suppress turbulence. This oil retained both these effects for more than 11 hours, and the process was repeatable, findings detailed online 13 January in the journal Physical Review E.
The scientists have also tested their device near Wichita, Kansas on a section of the Keystone pipeline, which brings oil from Canada to the United States. A major expansion of the Keystone network, called Keystone XL, is the focus of a big fight within the U.S. government. Many are opposed to the expansion on environmental grounds, such as concerns about oil spills and an added greenhouse gas burden of oil from the Canadian tar sands.
In the Keystone experiment the researchers found the device, which uses only 720 watts, could reduce pump power by 75 percent to 0.7 megawatts while maintaining the same rate of oil flow. They presented these additional findings at an American Physical Society meeting in San Antonio on 4 March.