Rather unusual approach used for upgrading heavy petroleum fees involves the use of ultrasonic energy, electric field and magnetic field. It should be noted that these methods are considered to be of an exploratory nature. Thus, it seems unlikely that any of these methods will be used on a commercial scale in a foreseeable future. However, their brief account may be useful because they differ markedly from the catalytic and non-catalytic methods which have been either under investigation or used for upgrading heavy petroleum feeds on a commercial scale.

The ultrasonic treatment was used to treat HGO at a near atmospheric pressure in the absence of additives (956). The lighter gaseous hydrocarbons produced were identified as methane, ethylene, ethane and propylene. The basic nitrogen-containing compounds in HGO were more easily cleaved by the cavitational energy than non-basic compounds. Maximum of the nitrogen and sulfur conversion of 11 and 7%, respectively, as well as a 5% reduction in viscosity, were obtained at the optimized sonochemical conditions. A radical chain mechanism was proposed to explain mechanism of the reactions of hydrocarbons which were initiated by ultrasound.

The information indicating the use of the ultrasonic treatment for upgrading the metals- and asphaltenes-containing feeds is limited, although the weak chemical bonds present in asphaltenes and porphyrin molecules may serve as potential sites for the cleavage followed by depolymerization (21, 39). For the asphaltenes, ¹H-NMR analysis before and after sonification revealed a significant decrease in the naphthenic structure (957). This involved both cracking and...