ISSN 1070-4272, Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 6, pp. 945!948. + Pleiades Publishing, Inc., 2006.
Original Russian Text + V.V. Tarasov, N.E. Kruchinina, S.A. Shilin, N.I. Shchedrova, 2006, published in Zhurnal Prikladnoi Khimii, 2006, Vol. 79,
No. 6, pp. 955!958.
PROCESSES AND EQUIPMENT
OF CHEMICAL INDUSTRY
Kinetics of Heterogeneous Hydrodynamic Coagulation
of Microscopic Drops
V. V. Tarasov, N. E. Kruchinina, S. A. Shilin, and N. I. Shchedrova
Mendeleev Russian University of Chemical Technology, Moscow, Russia
Received October 5, 2005; in final form, January 2006
Abstract-A prototype reactor for heterogeneous hydrodynamic coagulation of emulsions was developed
and tested. The efficiency of coagulation of water emulsions of some organic liquids was studied in relation
to process conditions.
Development of new methods for separation of
emulsions into constituent phases is a topical task.
Stable emulsions are the main reason for considerable
loss in oil production and for contamination of the en-
vironment with oils, fats, and oil products. Separation
of dilute emulsions of the [oil-in-water] type, i.e.,
raffinates produced in extraction of nonferrous, pre-
cious, rare, and radioactive elements, is also a com-
plicated problem. This is so because emulsions with
particles of submicrometer and micrometer size ([me-
dusas]), formed in radiochemical industry, show high
sedimentation and aggregative stability. Their separa-
tion requires application of special methods . Sep-
aration of the dispersed phase from the dispersion
medium occurs via coagulation (aggregation) of drops
with their subsequent coalescence.
The method of heterogeneous hydrodynamic co-
agulation (HHC), we suggest here, is implemented
in a batch installation (Fig. 1) [2, 3]. The stainless
steel reactor 1 of volume 500 cm
and inner diam-
eter of 80 mm, mounted on support 2, was charged
with 450 cm
of emulsion via opening 3 in cover 4.
An electric motor set in motion shaft 5 with plastic
discs 6 attached to it. The rotation frequency of the
discs was maintained constant in each set of experi-
ments. To preclude formation of a whirlpool, four cy-
lindrical reflector partitions 7 of diameter 4 mm were
installed in the reactor. Samples were taken at cer-
tain intervals of time via opening 3. Upon completion
of an experiment, the contents of the reactor were dis-
charged via bottom pipe 8. The experiments were per-
formed with 5 or 10 plastic discs of diameter 57 mm
with smooth and corrugated surface, with the dis-
tance between the discs equal to 10 and 5 mm, respec-
tively. All the experiments were carried out at 25oC.
The apparatus in Fig. 1 is shown without a thermo-
stating jacket. The unit maintaining the stable rota-
tion of the discs was of the PE-8310 type. The discs
were rotated by an electric motor at a strictly con-
stant to within 10% prescribed speed in the range
The coagulation and coalescence in the reactor we
developed necessarily involve immobile solid bodies
(reflector partitions and reactor walls) [2, 3]. Be-
cause the emulsion is composed of at least two fluids,
the process suggested here is to be regarded as occur-
ring in a fluid3fluid3solid system (i.e., heterogeneous
coagulation is meant). Moreover, the method being
described is performed in a system of moving fluids,
Fig. 1. Schematic of the installation for hydrodynamic
heterogeneous coagulation. For explanations see text.