APPLICATION OF REGRESSION METHODS TO BWR EQUATION FOR CALCULATION OF VOLUMETRIC AND THERMODYNAMIC PROPERTIES

This paper describes the methods used by the authors to revise the A.P.I. Project #44 selected thermodynamic properties tables for gaseous methane and gaseous ethane. For both gases, the experimental, literature, volumetric data were segregated into pressure — temperature or density — temperature regions. BWR coefficients were found for each region by various regression methods. A differential BWR equation is developed for the ethane project which guarantees continuity of the volumetric and thermodynamic surfaces at the interfaces between regions. Such data fitting techniques, which require the use of high‐capacity, highspeed, digital computers, are necessary for accurate representation of PVT data over wide ranges of pressure and temperature. Equations representing the volumetric properties of methane and ethane are presented and compared against the experimental data and the results of previous data representations. Copyright © 1969 Canadian Society for Chemical Engineering