A distillation column is a large vertical vessel used in the separation of mixtures based on differences in boiling points. It operates by heating a liquid mixture, causing it to vaporize. The vapor then rises through the column, where it cools and condenses at various levels, allowing for the collection of different components. Inside the column, there are trays or packing materials that enhance contact between the rising vapor and descending liquid. This process allows for the efficient separation of components, making distillation columns essential in industries such as petrochemicals, alcohol production, and water purification.