Hope College Engineering Department Research Experiences for Undergraduates Summer 2008 Project Summary

Chemical engineers use cubic equations of state to predict equilibrium properties such as vapor pressure and liquid and vapor densities.  The purpose of this research was to incorporate a quadratic approximation of the liquid density from a cubic equation of state into a vapor pressure prediction method.  Limiting behavior of both the Soave-Redlich-Kwong (SRK) and the Peng-Robinson (PR) equations at a low temperature limit were used as a basis for vapor pressure estimation for reduced temperatures up to 0.81 or higher.  The deviations between these estimates and the exact vapor pressure predictions of SRK and PR were quantitatively characterized and found to be represented by a unique expression of reduced temperature and acentric factor for all substances.  The estimates were additionally improved by incorporating a simple vapor fugacity correction based upon a virial equation.  These improved estimates deviated from the exact results by no more than 1.5 percent for PR and 7 percent for SRK.

_____________________________________________________________________________________________________________________________________________ Publications and Presentations:
Kowalsky, C.A., Lanser, J.L., Walsh, E.J., Wadelton, K., and Misovich, M.J., "Applying a Low Temperature Limit of a Cubic Equation of State to Model Pure Component Phase Equilibrium", AIChE Ann.Mtg. CD-ROM Proc. (2008). Conference presentations: Students Participate in Chemical Engineering Conference, November 14-17, 2008

Kowalsky, C.A., Lanser, J.L., Walsh, E.J., Wadelton, K., and Misovich, M.J., "Applying a Low Temperature Limit of a Cubic Equation of State to Model Pure Component Phase Equilibrium", Thirteenth Annual Michigan Space Grant Consortium Conference, Univeristy of Michigan, Ann Arbor, MI (2008)

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