Characterization of Crude Oils with Aspen Hysys and Aspen Plus

E. L. ALE RUIZ; A. RIVEROS ZAPATA; J. R. LEZAMA; E. ERDMANN; J. P. GUTIERREZ

Barcelona

Congreso; Congreso Mundial de Ingeniería Química (WCCE 10); 2017

In the oil industry, primary distillation is a dynamic process because the raw material and products vary depending on the reservoirs (suppliers) and the market demand for the products. Therefore, an adjustment study is necessary to adapt the variables of the fractionation process. These adjustments can cause serious problems of operation in the plants and consequently important economic losses. Thus, process simulators are used to perform the modifications and evaluate new operating conditions. Simulators can reproduce the operation of an industrial plant in both steady and dynamic state.Usually, engineers use powerful process simulation software to develop their work without having a proper background, especially a previous thermodynamic study applied to phase equilibrium. This lack of experience becomes evident when, for example, an incorrect choice of the fluid package is made, which will surely lead to erroneous solutions.The proper selection of thermodynamic models is absolutely necessary as a starting point for the simulation of a precise output information. If the simulation process is based on an inadequate thermodynamic model, the optimization of a process in terms of equipment selection, configuration and operation is useless. In the field of oil refineries, the starting point to simulate is the loading of the distillation curves, TBP or ASTM, and the subsequent characterization and analysis of crude oil.In the present article, different TBP distillation curves are introduced in two different commercial simulators, Aspen Hysys V8.8 and Aspen Plus V8.8. Then, the characterization and analysis of different crude oil as well as the advantages of each simulator, difficulties and results are compared. For the purpose, different crude oil curves and especially very heavy and very light crude from different basins are considered. A detailed study that includes the Chao-Sea and the Peng Robinson fluid packages is carried out for the characterization of each crude oil. In industrial plants, the heating unit operation is performed before the atmospheric crude oil distillation column. In order to perform the comparison of the fluid packages, a simple process of heating was also performed in each simulator.In the results, similarities between the ASTM D86 and ASTM D1160 curves are observed. A good approximation in the pseudo-components properties, VABP temperature, molecular weight, critical conditions, ºAPI, distillation curves and stream properties is also observed between the two simulators using both fluid packages. On the opposite side, significant differences in the characterization factor of pseudo-components K UOP and values of molar and mass entropies are observed.