ANS:A - distillation column

A distillation column is a key unit operation used in the chemical and petrochemical industries for separating liquid mixtures into their individual components based on differences in their boiling points. It utilizes the principle of fractional distillation to achieve this separation. Here's how a distillation column works:

1. Introduction of Feed: The liquid mixture to be separated, known as the feed, is introduced into the distillation column. The feed may consist of two or more components with different boiling points.
2. Vaporization: The feed is heated in the bottom of the column, causing it to vaporize. As the temperature increases, the component with the lowest boiling point vaporizes first, forming vapor. This vapor rises up the column.
3. Fractionation: Inside the distillation column, there are multiple stages or trays (or packing material) that facilitate the separation of the components. Each stage provides an equilibrium between the vapor and liquid phases, allowing for the transfer of components between the two phases.
4. Separation: As the vapor rises through the column, it comes into contact with the descending liquid. The components with lower boiling points preferentially vaporize and rise higher in the column, while the components with higher boiling points remain in the liquid phase and flow downward.
5. Condensation: At the top of the column, the vapor reaches a condenser where it is cooled. The vapor condenses back into liquid form, forming a distillate. The distillate typically consists of the more volatile components that have been separated from the feed.
6. Collection: The distillate is collected and may undergo further processing or be used as a product. Meanwhile, the remaining liquid in the column, known as the bottoms product, contains the less volatile components that did not vaporize and are removed from the bottom of the column.

Distillation columns can be operated at various pressures and temperatures to optimize separation efficiency and energy consumption. They may also include additional features such as reflux streams, reboilers, and condensate receivers to improve separation performance. Distillation columns are widely used in industries such as petroleum refining, chemical manufacturing, food and beverage processing, and pharmaceuticals for separating and purifying liquid mixtures into their individual components. They are essential in producing a wide range of products including fuels, solvents, chemicals, and beverages.