Molecular Simulations for Developing New Ethane/Ethylene Separation Processes

Separation of ethylene from ethane is by far the most challenging separation in the chemical industry simply because these two molecules have very similar sizes, shapes, and self-interaction strengths characterized by their closing boiling points. In spite of their relative volatility ranging between only 1.2 to 3.0, cryogenic distillation has been the preferred method for their separation. To develop new separation processes with the aid of molecular simulations, there is a compelling need for developing very accurate molecular models that capture these ultra-low separation factors. In this work, we develop an improved version of the Transferable Potentials for Phase Equilibria – United Atom force field. These newly developed models for ethane and ethylene are used to probe adsorptive separation using various zeolites. Furthermore, we investigate the sensitivity of the size of the separation column to the quality of molecular models and other assumptions that are employed in simulating the phase and sorption behavior.