Crude oil contains saturated hydrocarbon chemical components with boiling points that range from very low (methane) to very high. A small preflash column is frequently used upstream of the main pipestill to remove light ends and some of the naphtha to reduce the load on the pipestill furnace and column. The major design optimization variables in the preflash column include pressure, reflux-drum temperature, and furnace coil outlet temperature. This paper explores the design of a typical preflash column.