njit-etd1961-002 - New Jersey Institute of Technology

11The generalized compressibility factors were employedin calculating the specific volume in the. urated andsuperheated vapor regions. The average deviation ofexperimental values of Z from tabulated values varies fromzero at low pressures to 2.57 in the critical region andto 2.0% at high pressures.The values of the latent heat of vaporization weredetermined by the Watson method¹7. This method Iscapable of predicting data at all conditions up to thecrtical with errors generally less than 57 in magnitude.Corrections for departures from ideality of enthalpyand entropy were made using the generalized factorspresented by Hougen, Watson, and Ragatz¹. The accuracyfor these corrections for non-ideality is not available.However, it is believed they are reasonably reliable,especially with the introduction of a third parameterZc by Lydersen and et a1. 9The present investigation was the basis for thecompilation of tables of the thermodynamic propertiesfor formaldehyde. Although the values of these propertieswere mostly derived from generalized correlations andempirical equations, it is the author's opinion thatthese data are well within engineering accuracy requirementsfor design work. Nevertheless, reliable experimentalthermodynamic data should be used in preference to the datapresented In this paper whenever they are available.