API V31 Industrial Carbon Steel Distillation Columns Used In Crude Oil Refining

Distillation Columns Used in Crude Oil Refining

Yuhong Group Distillation Column is a critical piece of equipment in the refining of crude oil. Oil refineries use two main types of distillation columns which s below :

Packed Type Columns – A packed distillation column is a vertical tower packed in sections with ceramic raschig rings, ceramic saddles or steel pall rings. The packing material is used to increase the surface area for mass transfer between gas and liquid phases during the distillation process.

The process stream is heated before entering the column, which causes partial vaporization. As it moves up the tower, the vapor cools. Light components will continue to rise and heavier components will condense and fall to the bottom as liquid.

A reboiler at the bottom of the column adds heat to create vapor, which strips light components out of the liquid. Packed towers are typically onlyused to produce a top and bottom product.

Tray Type Column – Tray type distillation columns operate on the same principle as packed columns; however, instead of using packed material they use trays situated at various heights within the tower. The trays have a weir to maintain a layer of liquid across the surface.Hot vapor bubbles through the liquid to strip out light components. As the liquid flows over the weir, it is directed to the tray below.

There are three main types of trays in use: sieve, valve and bubble cap trays. Bubble cap trays generally achieve the most efficient separation of product components. The bubble cap design distributes the vapor more extensively, forcing it to bubble through the liquid flowing across the tray.

In general, tray type columns are more efficient than packed type columns, but are also more expensive. They do, however, facilitate multi-stage separation of products via side streams in the tower, and are therefore much preferred for crude oil distillation.

Distillation Columns Main Content :
Vertical Shell: The main body of the column, typically tall and cylindrical, where the separation of liquids occurs.
Reboiler: Situated at the base of the column, the reboiler heats the liquid mixture, causing it to vaporize and ascend the column.
Condenser: Located at the top, the condenser cools the vapour, causing it to condense into a liquid. This liquid can be collected or returned to the column as reflux.
Trays or Packing Material: Inside the column, there are either trays (also known as plates) or packing materials. Trays allow for the interaction between vapour and liquid, facilitating the separation process, while packing materials increase the surface area for vapour-liquid contact.
Feed and Withdrawal Points: The feed point is where the mixture to be separated is introduced. Withdrawal points are located at various heights for removing the separated components, known as fractions.
Reflux Drum: This component collects the condensed vapour from the top of the column. Part of this liquid (reflux) is returned to the column to achieve better separation.
Control Systems: These include temperature and pressure monitors and controllers that manage the conditions within the column to optimise the distillation process.
Supports and Insulation: Structural supports ensure the stability of the column, and insulation helps maintain the necessary temperature gradients.