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RESEARCH OF TECHNOLOGY FEATURES OF SODA PRODUCTION
Fayzullaev B.A.
1
PhD.
fayzullaevbayram@gmail.co
Baynazarov A.YA.
2
Tajibaev M.A.
3
1-2-3
Nukus Branch of Tashkent University of Information
Technologies named after Muhammad al Khwarizmi
https://doi.org/10.5281/zenodo.7089884
Abstract.
The basic block diagram of the technological process of soda production
is analyzed. The functional scheme of carbonation and absorption columns and the
properties of the liquid and gas phases in the production of soda have been studied.
Functional relationships between the parameters of absorption and carbonation
processes were considered as an object of mathematical modeling.
Keywords:
absorption, carbonation column, pressure, concentration, flow rate.
It is one of the most important products of the basic chemical industry. Soda ash
is widely used in many industries, as well as for household needs.
The main raw materials for the production of soda ash are sodium chloride (salt)
and calcium carbonate (limestone). On the territory of Uzbekistan, there are all
the main types of raw materials for its production [1-3].
One of the typical modeling objects is the technological scheme of soda ash
production (Fig. 1).
The functioning of the technological scheme of soda production is carried out as
follows. An aqueous solution of table salt, previously purified from calcium and
magnesium salts, enters the brine purification section 1. In the absorption section
3, the purified brine is absorbed by ammonia and partially by carbon dioxide. Part
of the ammonia lost during production is replaced by gaseous ammonia. The
ammoniated brine is pumped 4 to the carbonization section 5. Here the
ammoniated brine is saturated with carbon dioxide supplied by compressors
from the compression section 10, resulting in the formation of sodium
bicarbonate.
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Fig. 1. Technological scheme of the production of soda ash. 1-brine cleaning,
2,4,12-pumps, 3-absorption department, 5-carbonization department, 6
filtration, 7-calcination department, 8 - roasting department, 9 quenching
department, 10-compression department, 11-distillation, 13 - department of
heavy soda.
The precipitated sodium bicarbonate is separated from the liquid using a
drum vacuum filter in the filtration section 6. The filtered liquids are sent to the
distillation section 11 by pumps 12, and the sodium bicarbonate is fed into the
calcination section [2,3].
In calcination section 7, wet sodium bicarbonate decomposes when heated in
calciners to form light soda ash.
Light soda ash has poor thermal conductivity and occupies a large volume. To
change the crystal structure in industry, the method of recrystallization of soda
ash in solution is used. At the same time, soda with a large bulk mass is obtained,
heavy soda ash, in the department of heavy soda 13. In the distillation
department, ammonia is regenerated from the ammonium salts contained in the
liquid filtered from the precipitate of sodium bicarbonate. To do this, the filter
fluid is treated with steam and lime milk. The separated ammonia is returned to
absorption section 3.
According to [4], each compartment consists of several complexes, in turn, the
complexes consist of several apparatuses and devices in which various physical
and chemical processes occur (kinetic, heat and mass transfer, hydrodynamic, and
others).
2
4
12
NH
3
CO
2
NH
3
+CO
2
CaCO
3
NaCl
NH
3
+CO
2
CaCl
2
и др.
отходы
5
6
7
11
13
10
8
9
3
1
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For the purpose of analysis, we present the structure of physicochemical
processes and their interaction in the following form (Fig. 2).
On fig. 2 table salt (TS), heavy soda ash (SA), limestone (L), CaCl
2
and other wastes
(W), at intermediate stages, individual intermediates
Р
i
(I = 1,2,…,15).
J
i
(I =
1,2,…,10) departments in which
technological processes take place (devices,
devices), F
i
( I = 1,2,…,10) –
control actions.
Fig 2. The structure of physical and chemical processes and their
interaction.
It has been established that the main processes for the production of soda ash are
the separations of absorption and carbonization. Therefore, we will further
consider the main devices of these departments, the tasks of their automation, as
well as approaches to the mathematical modeling of such processes.
The absorption section uses bubbling and scrubber type devices to absorb NH
3
and
СО
2
. Modern and newly built soda plants are equipped with bubbling-type
apparatuses with a counter flow of gas and liquid. Bubbling apparatuses are
vertical columns consisting of a number of barrels connected by rubber gaskets
and bolted together. Each bubbling barrel has a special device - a bubbling plate,
on which there is close contact between gas and liquid. The apparatus has several
such plates sandwiched between flanges. When gas passes through the brine
layer, foaming of the liquid occurs, which contributes to better contact between
the gas and liquid phases.
To reduce equipment corrosion, sulfides are introduced into the brine, while the
internal surfaces of the apparatus are covered with a thin layer of iron sulfide,
which protects the equipment from further corrosion.
At operating soda enterprises, a process control system has been introduced at
stations in absorption departments, which collects, primary processes
information about the parameters of the technological regime, promptly
TS
J
1
J
2
J
3
J
4
J
5
J
6
J
7
J
8
J
9
L
SA
P
1
P
2
P
3
P
4
P
5
P
6
P
7
P
8
P
9
P
10
F
1
F
2
F
3
F
5
F
4
F
6
F
8
F
10
P
15
F
9
J
10
W
F
7
P
12
P
13
P
11
P
14
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calculates the main technical and economic indicators of the process and issues
these data to the operator.
The main parameter of the absorption section is the flow of the filter liquid into
the distillation column, which simultaneously determines the load of the
absorption apparatus by the amount of absorbed ammonia. The main streams,
including the purified brine for absorption and the water supplied to the cooling
of the apparatus of the absorption station, are subordinate and are coordinated
with the leading stream.
The main apparatuses of the carbonization department are the carbonization
columns and the first column gas scrubber.
The carbonization (precipitation) column is a vertical cylindrical bubbling-type
apparatus, consisting of separate cast-iron barrels and a drawer(similar to an
absorption column) [2].
The first gas washer of the column (GWC-1) is a scrubber-type apparatus, which
is a cylindrical hollow column with grates. In the upper part of the device there is
a distribution irrigation plate. The dimensions of the washers are determined by
the capacity of the carbonization section.
Currently, in practice, a system is used to control the processes of carbonization
and pre-carbonization of ammoniated brine, which provides for the automatic
supply of ammoniated brine to the pre-carbonization apparatus and maintaining
the liquid level in them, stabilizing the temperature regime of pre-carbonization
and the degree of saturation of the pre-carbonized liquid. The regulation of the
gas load in the pre-carbonization apparatus is carried out taking into account the
mode of operation of the precipitation carbonization columns.
The control system of the carbonization department of the soda ash production
solves the problem of optimal combination of high productivity of column
equipment with high sodium and carbon dioxide utilization rates
.
References:
1. Bespalov A.V., Kharitonov N.I. Control systems for chemical-technological
processes. Yoshkar-Ola, Mari Printing and Publishing Plant, 2007
2. Krashennikov S.A. Technology of soda ash and purified sodium
bicarbonate. Moscow, Higher School, 1985
3. Kaipbergenov, B.T., Fayzullaev, B.A., Elmuratov, M.K. Modeling of the
Technological Process of Ammonization of Soda Production Under
Conditions of Changing Initial Data, Advances in Intelligent Systems and
Computing, 2021, 1323 AISC, pp. 309
–
315
4. Kaipbergenov B.T., Fayzullaev B.A., Baynazarov A.Ya., Tajibaev M.A. To
the Question of Studying liquid levels in the Columns of Carbonization of
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soda Production. Science and Education in Karakalpakstan. No. 4/1 (19)
2021. Pp 128-134.
