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the use of a single construction for the whole diversity of petrochemical processes is inexpedient.
Knowing this, the "Giproneftemash" has worked out a series which includes the basic types of plates
presently used in the petroleum refining or petrochemical industry. To these types belong fractionating
columns with S-shaped, mesh-work or sieve plates having baffle elements. Later, four types of columns
with valved once-throughplateswere produced and introduced at the institute.
Of the four types presented, two types of plate - valved once-through plates and sieve plates with
baffle elements - were developed on an inventive level and have definite advantages compared to the best
foreign samples.
As a result of the investigative work carried out, it was established that the indicated column
types completely provide for both petroleum refining operations and petrochemical processes. For
example, columns with S-shaped plates are expediently used in processes taking place at atmospheric
or somewhat elevated pressures (at medium loads with respect to liquid). In vacuum distillation pro-
cesses, which are distinguished by large vapor flow rates and low liquid flow rates, it is more desirable
to use sieve plates with baffles, which have high productivity and low hydraulic resistance.
In processes which require a high degree of separation or which are accompanied by significant
load changes, the use of valved once-through plates is economically justified. This type of plate oan
also find wide application in separating thermally unstable substances (with a limited liquid residence
time in the column). In processes which take place under a significant excess pressure, where large
loads with respect to liquid are observed but there are no fluctuations in load, it is expedient to use
columns with mesh-work plates.
S-shaped plates (Fig.2), which are basic column units, determine column dimensions and the
quality of column operation (Table 1). The plate consists of S-shaped elements of identical profile which,
being connected with each other, form caps and gutters. On one side are located trapezoidal slots for
vapor passage, and on both ends of the vapor part of the element (the cap) are vapor chokes to prevent The hydraulic resistance of the S-shaped plate compared to bubble cap plates is shown in Fig.4a,