What is stripping in distillation



The Rectification column is a process engineering device for the thermal separation of materials. The separation is carried out by rectification (multi-stage distillation).

function

see column and rectification.

construction

The column forms a cylindrical container with internals that intensify the heat and mass transfer. The evaporator is arranged below the bottom of the rectification column and the condenser is connected behind the top of the column. Depending on the type of internals used, a distinction is made between tray, packed and packed columns. The vaporized mixture of the substances to be separated is fed in through an inlet at the bottom of the column. The lower-boiling component accumulates towards the top and can be drawn off there, while the higher-boiling component is returned. The higher-boiling component accumulates in the sump and can be removed there.

There are three types of built-in components:

  1. Sieve, bubble cap or valve trays on which the liquid stands are installed in tray columns. The vapor is bubbled into the liquid through special slots or holes, creating a bubbly layer. A new temperature-dependent equilibrium is established between the liquid and gas phases on each of these soils.
  2. Packed columns can be filled with different packings, which cause good distribution of the liquid and turbulence in the gas flow. The increase in the surface area of ​​the approximately 5-15 mm particles optimizes the exchange of heat and masses and thus increases the separability of the column. Well-known examples are the Raschig ring (a hollow cylinder), Pall ring, Hiflow ring, Intalox saddle, Berl saddle and hedgehog. The packing can be arranged in order, but also randomly (as a bed) introduced into the column. The materials that can be used are glass, ceramics, metal and plastics.
  3. Structured packings are a further development of the ordered packing. They have a regularly shaped structure. In the case of packings, this makes it possible to reduce constrictions for the gas flow (with a considerable influence on the pressure loss). There are different types of packs, e.g. B. tissue or sheet metal packs. Metal, plastic, glass and ceramic (depending on wettability) can be used as material. There are packs from many major manufacturers with different names and preferred areas of application.

See also

Categories: Technical Chemistry | process technology