Vapor pressures of high‐boilings complex hydrocarbons

Abstract Since vapor pressures of very high‐boiling hydrocarbons are of increasing interest in energy‐related processes, a new correlation has been established for estimating these vapor pressures over a wide range of temperature. The new SWAP correlation, based on Prigogine's theory for polysegmented molecules, is particularly useful for hydrocarbons (and petroleum cuts or coal tars) which deviate from normal‐paraffin structure: branching, saturated and unsaturated rings. Extensive comparison with experimental data shows that whereas for normal paraffins SWAP gives results comparable to those obtained by previously‐published correlations, SWAP gives significantly better results for large aromatic, naphthenic and branched hydrocarbons. To use SWAP, the only input data required are T 10 (boiling point at 10 mm Hg) and approximate characterization of molecular structure.