E. López-Chávez

Methodology for Predicting the Phase Envelope of a Heavy Crude Oil and Its Asphaltene Deposition Onset

Abstract We have presented general ideas to develop a new theoretical methodology, based on molecular simulation and equations of state, for obtaining the phase envelope and to predict pressure, volume, temperature (PVT) conditions of asphaltene precipitation by only taking into account the composition of the heavy crude oil and an asphaltene average molecular structure. Those results show that asphaltene precipitation is a reversible thermodynamic process. The precipitated phase is a liquid phase which consists of mainly asphaltene and some heavy fractions from the crude. This methodology can be applied to find complete phase diagrams of different crude oils based on an asphaltene average molecular structure and the composition of crude oil.

Molecular Simulation of Ion-Transport inside Chitosan Membranes

We have presented general ideas to develop a theoretical methodology, based on Molecular simulation and Einstein equation aimed to describe the mechanism and behavior of chitosan-membrane ion conductivity and to obtain its magnitude for different ionic species. Atomistic molecular modelling has been utilized to construct an ionic-conducting polymer electrolyte system consisting of poly(chitosan), H O 2 molecules, and + H O 3 , − OH , 2− 4 SO ions, inside of the simulation cell. The COMPASS force field was used. The simulation allows describing the mechanism of ionic conductivity along the polymer matrix. The theoretical results obtained are compared with previously-reported experimental data for chitosan membranes. The present methodology can be considered as a first step towards understanding these complex problems of technological interest.