Effects of ultrasonic irradiation on the viscosity of fuel oils

Fuel oil A, B and C, and a residual oil from vacuum distillation (R-Oil) have been irradiated with 25kHz ultrasonic waves (150W) at 50 °C for 10 h. The observed increases in the kinematic viscosity (Δ v%) are: fuel oil A, 0.3%; fuel oil B, 5.3%; fuel oil C, 17.6%; and R-Oil 5.5%. The value and sign of Δ v are found to change with the sample weight in the flask, l.r. measurements show that ultrasonic irradiation causes the intensities of CH₂ and CH₃ to decrease slightly. The ultrasonic energy appears to be used in the breaking-up and/or coupling of the petroleum molecules.