point components. The weight factor is then determined for each component as
before. Note that sulfur content is always quoted as a percent weight. Using the
relationship of percent sulfur to mid-boiling point given in the assay, the sulfur
content of each component is read off. This is multiplied by the weight factor for
each component to give a sulfur factor. The sum of the total sulfur factors divided
by the total weight factor gives the weight percent sulfur content of the fraction. For
example, using the same gas oil cut as before, its sulfur content is determined as
shown in Table 5.
600
TBP
500
400
300
0
1 0
2 0
3 0
4 0
5 0
6 0
% Vol
70
80
90
100
ASTM
EFV
°F
Fig. 8 Types of distillation curves
24
D.S.J. Jones