135Combustion of Used Engine Oil
Before dealing with the combustion of the mixtures, it is necessary to determine
the range of miscibility of these two kinds of fuels, which varies owing to the struc-
ture of the hydrocarbons they contain. The used engine oil structure is parafnic
because of its multigrade character, which is achieved during its renery manufac-
ture (extraction of polynuclear aromatic compounds). On the other hand, heavy fuel
oil, mainly composed of the petroleum crude residual fraction, contains three classes
of well-differentiated products: (1) asphaltene constituents, more or less agglomer-
ated, condensed compounds of high molecular weight; (2) resins constituents, with
structures intermediate between asphaltene constituents ...