Fractional composition is an important indicator of the quality of oil. In the process of distillation at gradually rising temperatures of the oil was removed parts - fractions differing boiling range.
The atmospheric distillation the following fractions boiling up to 350 ° C - light oils:
up to 100 ° C - petroleyvaya fraction;
up to 180 ° C - gasoline fraction;
140-180 ° C - naphtha;
140-220 ° C - kerosene fraction;
180-350 ° C (220-350 ° C) - the diesel fraction.
Recently, the fraction boiling up to 200 ° C, referred to as the lungs, or petrol, from 200 to 300 ° C - average, or kerosene, above 300 ° C - heavy or oily.
All the fractions boiling up to 300 ° C, referred to as light, the remainder after the selection of light distillates (above 350 ° C) is called black oil. Fuel oil distilled under vacuum to afford the following fractions as a function of processing:
for fuel (350-500 ° C) - the vacuum gas oil (vacuum distillate);
500 ° C - the vacuum residue (tar).
Getting oil occurs in the following temperature ranges: 300-400 ° C - light fraction, 400-450 ° C - the average fraction, 450-490 ° C - heavy fraction, over 490 ° C - tar. Asphaltene deposition (AFS) is also referred to as heavy oil components - Tm ~ 80 ° C.