Influence of High Molecular Weight Components on Heavy Fuel Oil Behavior in Heating and their Combustion Characteristics.

Commercial heavy fuel oils with relevant content (8-12%) of heavy components (asphaltenes, malthenes and resins, metal-porphyrins, polycyclic aromatics) give rise to problems of handling, stocking and use. Looking at the nature of these components and their behavior in heating, the most interesting correlations between low boiling ( less than 300 degree C) products, asphaltenes content, Conradson carbon residue and unburnt particulate formation during combustion, particularly in medium-small size thermal units, are considered. To decrease particulate emission, residence time within the flame must be increased, favoring a further flame widening in low confinement combustion chambers, and raising the flame axial momentum (for a stronger external recirculation) in confined chambers. The use of additives to improve the oil characteristics is briefly considered as well as the increase of thermal unit flexibility reached using water oil emulsions.