Molecularly Explicit Characterization Model (MECM) for Light Petroleum Fractions

A method is developed for simulating undefined multicomponent mixtures such as petroleum
fractions, coal liquids, and gas condensates using a preselected set of pure components. The
molecularly explicit characterization model (MECM) uses routinely made measurements of a
petroleum fraction's bulk properties such as the ASTM D86 distillation, API gravity, Reid vapor
pressure (RVP), and the paraffin, naphthene, and aromatic (PNA) content along with the pure
components' properties in an optimization algorithm to define the molecular composition of the
petroleum fuel suitable for simulation purposes. The model is tested using a set of 68 pure
components to characterize petroleum naphtha and simulate its separation in a distillation
column. This model is found to be of better accuracy than the characterization methods currently
used. The method has the flexibility to be tailored to use any set of pure components as desired
and may further be used to predict the properties of petroleum fractions.