A client needed information on crude oil characteristics, in particular physical properties (density, viscosity, vapor pressure, flash point, etc) of Bakken crude oil at temperatures −40 to +60 deg C. Vapor pressure is usually measured for a particular crude oil according to a standard ASTM method. For pure compounds, Antoine coefficients are available for estimating vapor pressure at a given temperature according to the Antoine or other equations. One approach to estimate the vapor pressure of a complex hydrocarbon mixture (like crude oil) is to pick an aromatic and a saturated hydrocarbon having the same boiling point as the initial boiling point of the crude oil, and use the Antoine equation for those two compounds to estimate (conservatively) the v.p. of the crude oil.
Joseph Sabol, PhD
Chemist and Chemical Consultant