ABSORPTION COLUMN (EN: absorption tower, absorber, absorption columABSORPTION COLUMNn; DE: Absorptionskolonne, Absorptionsturm, Absorbierkolonne; FR: colonne d'absorption; ES: torre o columna de absorcion; RU: абсорбционная колонна), the heat and mass transfer apparatus for the separation of the gas mixtures by the selective absorption of the individual components in the liquid absorbent material. It is used in the drying and purification of the natural gases, in the production of the sulfuric acid, chlorine, ammonia, etc.

The absorption occurs at the surface of the media separation, thus the absorption columns have the developed surface for the mass transfer between the liquid and the gas, and the absorption columns are conventionally divided into the 4 groups according to the method of the forming of such surface.

In the surface absorption columns the gas passes over the surface of the stationary or the slow moving liquid; in the more effective film absorption columns the contact of the phases occurs on the surface of the flowing liquid.

In the packed absorption columns (the type of the film absorption column) the contact of the phases is carried out on the surface of the solid bodies of the various shapes, filling the working volume of the apparatus, the so called packings. The fluid flows down the packing as a thin film, which is washed by the gas.

The bubble cap (sieve plate) absorption columns have the plates, which are placed within the column at the certain distance one from another. The gas rises up and passes through the layer of the liquid on the plates (through the holes or the special valve devices). The fluid flows through the overflow pipes down from one plate to another.

In the spray absorption columns, the contact between the phases is achieved by the pulverising or spraying the fluid inside the column in various ways.

On the picture. The bubble cap (sieve plate) absorption column (1 - the drainage, 2 - the manhole, 3 - the blank plate, 4 - the sieve plates, 5 - the wire mesh of the droplet separator).

Some information may also be found in the relevant article on the Wikipedia.