AbstractChanges in the dispersion state of heavy fuel oil with dissolved hydrogen sulfide, occurring under the action of low-energy wave treatment, were studied. Treatment with ultrasound and constant magnetic field ensures the reduction of the hydrogen sulfide content of the fuel oil to less than 10 ppm, and even to 1 ppm when the treatment is combined with using absorbents. The optimum parameters of the wave treatment were determined. The mean particle diameter of the dispersed fuel oil phase passes through a maximum in the course of wave treatment. The mechanism of processes occurring in the course of hydrogen sulfide removal from heavy fuel oil, based on concepts of petroleum disperse systems, was suggested.