Strategies for Applying VLE Routines

For some problems, such as generation of a phase diagram, the examples in this chapter can be followed directly. Often, however, it takes some thought to decide which type of VLE routine is appropriate to apply in a given situation. Do not discount this step in the problem solution strategy. Part of the objective of the homework problems is to increase understanding of phase behavior by encouraging thought about which routine to use. Since the equation of state routines are complicated enough to require a computer, they are also solved relatively rapidly, once the VLE routine has been identified. Use Table 10.1 on page 373 and the information in Section 10.1 to identify the correct procedure to apply before turning to computational techniques. Use the problem statement to identify whether the liquid, vapor, or overall mole fractions are known. Study the problem statement to see whether the P and T are known. Often this information together with Table 10.1 will determine the routines to apply. Sometimes more than one approach is satisfactory. Sometimes the ideal-solution approximation may be applied, and a review of Section 10.8 may be helpful. Before using software that accompanies the text, be sure to read the appropriate section of Appendix A, and the instructions or readme.txt files that accompany the program.