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from one phase to another convection and molecular diffusion: absorption and
adsorption, distillation and rectification, extraction, drying, crystallization. Mass
transfer - the process of transfer of substances from one phase to the other in the
direction of achieving equilibrium.
The driving force mass transfer processes is the difference between the
actual and equilibrium concentrations of the rolling material. Spontaneous
achieving equilibrium concentration of the rolling material in the first and
second phases is called diffusion.
Absorption
is called absorption process gases or vapors from the gas or
vapor mixtures by liquid - absorbent, ie substance is a transition from the gas or
vapor to the liquid.
This process is a selective and reversible, which allows to use it in order to
obtain solutions of gases in liquids and for separation of gas or vapor mixtures.
The food absorption processes are used to clean the deferent gases to
capture valuable products or neutralization bleed.
In various food technologies, for example, for purifying the raw juice and
sugar syrups, clarification of fruit juices and beer, alcohol purification from
organic impurities, brandy, vodka, wines et al., using the adsorption process.
Adsorption process is called absorption gas or vapor from gas mixtures or
solutions of solutes solid sorbents - adsorbents.
In food production following adsorbents are used extensively: activated
carbons, silica gels, zeolites, clays, and others.
In physical adsorption takes place the mutual attraction of the molecules of
the adsorbent and adsorptive under the action of van der Waals forces. In
chemical adsorption characterized by the formation of a chemical bond between
molecules adsorbed substance and the adsorbent, which is a result of a chemical
reaction.
The adsorption process is selective and reversible, making possible the
absorption of one or more components and then, under certain conditions their
separation from the adsorbent.
Distilling and rectifying - the most common methods of separating liquid
homogeneous mixtures consisting of two or more volatile components, i.e. there
is a transition from liquid phase to vapor and vapor to liquid.
The processes of distillation and the distillation is widely used in the
production of ethanol, in the production of aromatics. Distillation receive cognac
alcohol, ethyl alcohol, used in the production of cognac, whiskey, brandy, rum
and others.
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