“…1. Maximum distillate problem: collection of maximum amount of distillate with specified concentration in a prescribed final time (Converse and Gross, 1963;Keith and Brunet, 1971;Murty et al, 1980;Diwekar et al, 1987) 2. Minimum time problem: minimization of final distillation time to produce a given amount of distillate with specified concentration (Coward, 1967a, b;Robinson, 1969Robinson, , 1970Mayur and Jackson, 1971;Egly et al, 1979Egly et al, , 1983Hansen and Jorgensen, 1986;Mujtaba and Macchietto, 1988) 3.…”