Hope College Department of Physics and Engineering
Research Experiences for Undergraduates
Summer 2006
Project Summary

 

Project Title:

Improving Accuracy of Vapor Pressure Prediction by Varying Expansion Temperature

Student Name: Meg Estochen
Student's Home Institution: Hope College
Research Advisor: Dr. Michael Misovich
Source of Support: National Science Foundation under NSF-REU Grant No. 0452206
The purpose of this research was to improve prediction of vapor pressure as a Taylor series expansion in temperature for a cubic equation of state such as the Soave-Redlich-Kwong (SRK). The ability to model physical properties from limited information is essential to practicing chemical engineers. Series methods for vapor pressure prediction typically are expansions about the critical point. Many terms are required to minimize truncation error at lower temperatures. A method was applied to change the expansion temperature in a truncated series with an added correction term. The best of 118 tested combinations was an expansion temperature of 0.7 with three initial series terms and one correction term. The truncation error was less than 0.1 percent for reduced temperatures between 0.72 and 1.0 when the acentric factor was 0.8, and for reduced temperatures between 0.57 and 1.0 when the acentric factor was zero, comparable in accuracy to a thirteen term series expansion about the critical point.

*This material is based upon work supported by the National Science Foundation under NSF-REU Grant No. 0452206.