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Petroleum Processing

Cut Points

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Cut Points

Using a crude TBP curve, cut points are defined as the temperatures that represent the limits of a distillate fraction, as illustrated in Figure 4.11. For example, for kerosene, fraction Ta represents the lower cut point, and Tb represents the upper cut point in Figure 4.11.

Temperature on y, % distilled on x. Cut points intersect with BP line showing starting point of the distillate fraction
Figure 4.11. Cut points and definition of distillate products as boiling ranges.
Source: Dr. Semih Eser

Boiling ranges between the cut points represent distillate products, such as naphtha, kerosene, light gas oil, etc. The difference between the cumulative volume percent at upper and lower cut points is reported as the yield (in volume %) for the particular distillate fraction. For example, for the crude represented in Figure 4.11, the kerosene yield can be calculated as 40%(at Tb) -20% (Ta) = 20% by volume. Table 4.1 shows the TBP cut points for crude oil distillate fractions.

Table 4.1 TBP cut points for crude oil distillate fractions.
Distillate Product Boiling Range
Butanes and Lighter
Light SR Naphtha 90 - 190o F (32-88o C)
Heavy Naphtha 190 - 380o F (88 - 193o C)
Kerosene 380 - 520o F (193 - 271o C)
Light Gas Oil 520 - 610o F (271 - 321o C)
Heavy Gas Oil 610 - 800o F (321 - 425o C)
Light Vacuum Gas Oil 800 - 950o F (425 - 510o C)
Heavy Vacuum Gas Oil 950 - 1050o F (510 - 564o C)
Vacuum Residue > 1050o F (>565o C)