For an ideal ternary mixture of benzene, toluene, and p-xylene (BTX), vapor-liquid equilibrium data can be computed using Raoult’s law, y_iP = x_iP_i^sat, where P_i^sat is the vapor pressure of component i given by Antoine’s equation, P is the total pressure, and x_i and y_i are the liquid and vapor phase mole fraction of component i. Select a feed composition by dragging the locator in the ternary triangular diagram (i.e. inside the gray region). Vary the values of P and T using the sliders. This simulation computes the vapor fraction φ of the feed and the composition of the liquid and vapor streams leaving the isothermal flash drum. Only when T_bubble < T < T_dew will the feed be a two-phase mixture such that 0 < φ < 1.