<P> The K factor or characterization factor is a systematic way of classifying a crude oil according to its paraffinic, naphthenic, intermediate or aromatic nature . 12.5 or higher indicate a crude oil of predominantly paraffinic constituents, while 10 or lower indicate a crude of more aromatic nature . The K factor is also referred to as the UOP K factor or just UOPK . </P>

Based on watson characterization equation explain the significance kw in petroleum refining