Expanded density (EXD)

For cuts where the weight yield is 70% or less, expanded density equals density. For wider cuts, including the whole-crude stream, expanded density is usually slightly lower than density. (Expanded refers to volume.) Comparing density and expanded density provides a measure of volume expansion.

Expanded density is always calculated from the component-wise density profile using Equation 1 (see Existing calculations in USC Assay). The whole-crude density value is not used, and there is no special treatment for wide cuts.

For the whole crude, density and expanded density can be interpreted as follows:

(Equation 3)

(Equation 4)

In Equation 4, no single product is assumed to contain more than 70% by weight of the crude.