Low temperature behaviour of refined products from DSC measurements and their thermodynamical modelling

The low temperature behaviour of five distillation cuts (230–375°C) from crude oil from different sources (North Sea, Africa and Middle East) provided by the Portuguese refinery Petrogal, was studied. Precipitation curves for these cuts, showing the evolution of the fraction of solid n-alkanes with temperature, were measured by DSC and the compositions of the cuts were analysed by gas chromatography (GC). The measured precipitation curves have been compared with the predictions from a thermodynamical model using the compositional analysis. The model results agree well with the experimental data indicating that the model used can be an adequate tool to predict the low temperature behaviour of refined oil products.