A distillation column achieves separation by exploiting differences in the volatility of the various components within a mixture. The feed is typically preheated before entering the column. A reboiler at the bottom provides heat, vaporizing a portion of the liquid, which then rises through the column; meanwhile, a condenser at the top liquefies the vapors, with a fraction of this condensate returned to the column as reflux. This reflux repeatedly contacts the ascending vapors on the surfaces of trays or packing. More volatile components become progressively concentrated toward the top of the column, while less volatile components accumulate toward the bottom, allowing them to be withdrawn from different locations. The actual separation performance depends on factors such as phase equilibrium, column internals, reflux conditions, and operating pressure; therefore, the final purity cannot be determined solely based on differences in boiling points.