The operator of the trans-Alaska oil pipeline plans a project this winter to heat up the crude by recirculating it through one of the pump stations.
It’s part of efforts to deal with issues arising from declining throughput on the pipeline, which carries North Slope oil 800 miles to the Valdez tanker port.
Because less oil is entering the pipeline as field production wanes, the oil is taking longer to travel to the other end. As a result, oil that enters the line at around 110 degrees Fahrenheit is cooling excessively, inviting problems such as water freeze-ups in the line, greater wax buildup, and frost heaves stressing buried sections of pipe.
For the upcoming winter, Alyeska Pipeline Service Co. plans to “perform enhanced recirculation of crude oil passing through Pump Station 7,” company spokeswoman Katie Pesznecker told Petroleum News in an Oct. 6 email.
“We will begin recirculation this month (October) and continue through the winter,” the email said. “Recirculation adds heat to the crude oil by passing a portion of the oil through pumps twice: It enters at one temperature, gains heat, then passes through the pump again, exiting at a higher temperature. This will improve our thermal profile going into the colder winter months.”
—Abbreviated reprint from the Oct. 23, 2011, issue of Petroleum News, by Wesley Loy
