Estimation of crude oil TBP from crude viscosity

► Model for crudes TBP express estimation from crude kinematic viscosity was derived. ► Sub model for crudes pseudocomponents VBNs from their ABP was derived. ► We reported an error for prediction of crude TBP cut boiling up to 340°C of 5.95%. ► The error for prediction of API light crudes TBP cut boiling up to 340°C is 3.74%. Crude oil TBP curves are well recognized as an important characteristic, needed to determine the potential of fractions obtained by distillation, to monitor distillation units, to verify the identity of crude oil samples, etc. They can be obtained experimentally or calculated by a variety of methods, which have different precision. The precision of the particular method determines the applicability of the obtained TBP data. Riazi’s two-parameter distribution model and experimental crude assay data for 117 crudes from all over the world have been used to derive a model for prediction of true boiling point (TBP) curves from the kinematic viscosity of the samples at 37.8°C. The model was tested by prediction of the cumulative mass fractions of all studied crude samples. It was found that the TBP distribution for fractions boiling up to 340°C could be predicted with an average relative deviation of the order of 5.95%. This is higher than the respective deviation of previously proposed models, e.g., Riazi’s model, with an average deviation of 3.3%. Due to that reason the model was improved for prediction of light crude true boiling point (TBP) curves. It results to falling down of the average relative deviation to 3.74%. However, these models require experimental data for several properties, while in practical terms the precision of our model is sufficient to detect any significant upsets in the operation of refinery crude distillation units (CDUs), so its computerized procedure may be used as a quick tool for monitoring of the CDU operation.