The purpose of this study was to assess the feasibility and experimental conditions for the shearing of polymers (polyolefins) in fuel oil. These drag-reducing agents are mixed with fuel oil to reduce the friction during transportation in pipelines and, hence, to save energy, but they Must be destroyed after use to restore all the properties of the fuel. One attractive solution consists of the use of ultrasonic energy to carry out this destruction. Ultrasound produces microbubbles (cavitation) in liquids. These bubbles grow and finally collapse, releasing a large amount of energy as a shockwave that can break polymer chains. We studied the influence of parameters affecting cavitation on the shearing index (percentage of initial additive after sonication). We concluded that polymers A and B Could be used indiscriminately. The ultrasonic energy could be injected at a frequency of 20 kHz (like in commercial equipment), and the mode of injection did not influence the yield. The results were similar in static and flowing fuels. The temperature did not exert a significant influence. (c) 2006 Wiley Periodicals, Inc.