Absorbers. Description and types

1. Superficial

Here in turn subspecies enter:

o superficial absorbers (in them the surface of contact of two phases is a mirror of liquid);

o film absorbers (the liquid film surface participates in process);

o nozzle absorbers (they have a special nozzle, on which of bodies of different forms (lumpy material, rings etc.) flows down liquid.);

o film mechanical absorbers.

In general, the surface of contact for such type of absorbers is defined by geometrical parameters of a surface of elements (for example, the same nozzle), but isn't equal to it in many cases.

Bubbling

In bubbling absorbers the surface of contact depends on the hydrodynamics mode - (expenses of liquid and gas). In this option the surface of contact is developed by flows of gas which distributes liquid in the form of streams and bubbles. Similar gas flow is called bubbling, from here and the name of the device went. Process happens by filling of the device with liquid and a transmission of gas through it. Such experiments can be made also in two other versions: nozzle absorbers and bubbling absorbers of columned type which have special plates of various type.

Here the option of bubbling absorbers in which liquids mix mechanical mixers enters.

Spraying

In these absorbers the surface of contact the same as at bubbling absorbers, depends on the hydrodynamics mode, but differs in an education method: in this case liquid in the lump of gas is sprayed on small droplets.

In turn they are divided into subspecies too:

Forsunochnye's o (liquid is sprayed by means of nozzles);

o High-speed direct-flow (liquid is sprayed in current of the gas moving with high speed);

o Mechanical (liquid is sprayed by means of the rotating mechanical devices).

In the considered option the taken component is also used therefore it is allocated by means of process of a desorption and sent for further conversion. When the quantity of the taken component isn't enough and the absorber doesn't bear special value, after absorption solution is merged in the sewerage.

It is possible to give purification of gases of oil and coke of H2S, on servicews of sulphurous gas in case of receipt of sulfuric acid as examples, clarification of mix of nitrogen and hydrogen to synthesize ammonia. Cleaning on sanitary standards of furnace flue gases of SO2, cleaning of an absorber gas (it is the emitted steam-gas mix) after chlorine condensation process in the liquid state, from fluoric gases which come out when receive mineral fertilizers and many others is often used.

From descriptions of ways of applications in a chemical industry it is possible to draw a logical conclusion that absorption is often combined with a desorption. Such combination allows to use an absorber many times and in pure form to allocate the absorbed component. That to receive it, solution after stay in an absorber right there is directed to process of a desorption where the necessary component is allocated, and (regenerated) solution exempted from him is returned for new absorption again. At this scheme of circular process the absorber is practically not spent (apart from his absolutely insignificant losses) and constantly undergoes circulation like absorber — the desorption device — an absorber.

In case of existence of an invaluable absorber repeated use of an absorber isn't carried out at process of a desorption, after the absorber released in the desorption device thrown out in the sewerage, and in an absorber put new.

Today for all types of devices there is yet no rather reliable way which could allow to define mass transfer coefficient by calculation or relying on laboratory trials or model options. Nevertheless, for some types of devices gradually it is possible to find them even by means of enough simple experiences and reliable accuracy(see; fig.1).

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