Enthalpies of components in ideal gas mixtures can be computed from existing data. However the isothermal effects of pressure and composition on partial enthalpies of mixture components have not been completely characterized. An investigation of the application of the Redlich-Kwong equation of state to the calculation of partial enthalpies is reported here. Methods are developed for convenient hand calculations and for computations on the IBM-650.

Calculated partial enthalpies are compared with values derived from experimental P-V-T-C data for binary hydrocarbon mixtures. The calculated values agree fairly well with the derived data for pressures up to 2,500 lb./sq. in. abs. Best agreement is generally obtained when the mixture is well above the critical temperature of the more abundant component. No consistent bias was indicated however.