This program is designed to run in an interactive mode. It has the capability of doing both flash calculations and short cut distillation calculations, both with multi-component systems. The thermody namics package is very general, with the vapor phase fugacity calculated by the Redlich-Kwong equa tion of state. The liquid phase is considered a non-ideal solution with activity coefficients based upon the Hildebrand solubility parameter. The short cut distillation module uses the Fenske total reflux equation, Underwood's equation for minimum reflux, and the Eduljee version of Gilliland's correla tion for number of stages and reflux ratio for the rating mode.

The short - cut distillation package requires the user to specify the ratio of reflux rate to minimum reflux rate, presssure of the column, and fraction of the light and heavy key. The output from the programs gives composition and physical properties (including K values) for the products, number of stages, feed stage and condenser and reboiler duties. The column is sized and the capital and operating costs are calculated. (The user can change the economic parameter if desired). The equivalent uniform annual cost (EUAC) is also calculated.

The parameters needed to fully specify a distillation are the component identification and flow rates, the pressure and temperature of the feed (and the column pressure is kept at the feed pres sure), whether a total or partial condenser is used, the light and heavy keys with their splits, and the ratio of reflux to minimum reflux. The economic parameters needed to calculate operating costs are cooling, heating, and refrigeration costs based on a basis of $/10 6 Btu for standard conditions. If the conditions of the column are not standard the costs are adjusted to relfect the lower or higher tempera tures. The economic parameters needed to calculate the capital cost are the CE index, and the Lang factor. Correlations are used to determine the diameter of the column, and the cost of the column, trays and heat exchangers. To calculate the EUAC other parameters are needed: the tax rate, project lifetime, depreciation and salvage information, and the internal interest rate.

The program can be run with three nested loops. The inner-most loop permits the changing of the column pressure, fraction of light and heavy key, and ratio of reflux to minimum reflux. The next most inclusive loop permits one to change all parameters except the component identification. The largest loop permits one to change all the parameters. The inner-most loop is convenient for optimiz ing a column since the program gives economic results quickly for each change in the major operating parameters.