Volume 03 Issue 11-2023
188
International Journal of Pedagogics
(ISSN
–
2771-2281)
VOLUME
03
ISSUE
11
P
AGES
:
188-194
SJIF
I
MPACT
FACTOR
(2021:
5.
705
)
(2022:
5.
705
)
(2023:
6.
676
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
ABSTRACT
The process of obtaining benzene and its homologues based on pyrolysis distillation has been implemented, the
quantitative and qualitative composition of pyrolysis distillate samples and the processing of their fractions have been
studied. Qualitative analysis was carried out by IR spectroscopic method, quantitative composition was studied by gas
chromatograph with mass spectroscopy.
KEYWORDS
Pyrolysis distillate, benzene, toluene, xylene, methylethylbenzene, propylbenzene qualitative and quantitative
analysis.
INTRODUCTION
In the Republic of Uzbekistan, the presence and
expansion of pyrolysis production makes it possible to
produce pyrolysis benzene by pyrolysis of gas
condensate and catalytic reforming of oil products,
followed by extraction separation of catalysts and
pyrocondensates with selective solvents [2].
To date, universal extractants have not yet been found
that combine high separation selectivity with a
sufficiently high dissolving ability and fully meet the
requirements of modern technology. Therefore, the
search and study of the extracting properties of
effective polar solvents for the production of benzene
in Uzbekistan is an extremely important and urgent
national economic task.
Benzene is the most important raw material of the
petrochemical industry, on the basis of which large-
scale organic synthesis products are produced.
According to Rosstat, the volume of benzene
production (including from pyrolysis products and
petroleum) amounted to 1,200 thousand tons.
Research Article
USE OF PYROLYSIS DISTILLATE RAW MATERIALS FOR OBTAINING
BENZENE
Submission Date:
November 20, 2023,
Accepted Date:
November 25, 2023,
Published Date:
November 30, 2023
Crossref doi:
https://doi.org/10.37547/ijp/Volume03Issue11-36
Jurayeva Laylo Rakhmatullaevna
Bukhara Engineering And Technology Institute, Department Of Chemistry, Uzbekistan
Journal
Website:
https://theusajournals.
com/index.php/ijp
Copyright:
Original
content from this work
may be used under the
terms of the creative
commons
attributes
4.0 licence.
Volume 03 Issue 11-2023
189
International Journal of Pedagogics
(ISSN
–
2771-2281)
VOLUME
03
ISSUE
11
P
AGES
:
188-194
SJIF
I
MPACT
FACTOR
(2021:
5.
705
)
(2022:
5.
705
)
(2023:
6.
676
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
According to experts from the Industrial Information
Agency, global demand for benzene will grow by an
average of 5.2% per year and will amount to 41 million
tons. The fastest growth will be observed in Asia
(excluding Japan) - an average of 7.5% per year - and in
other regions of the world - 13.6% (mainly in the Middle
East and South America). The main increase in benzene
production volumes will occur due to the introduction
of new capacities, as well as due to an increase in the
production of pyrolysis benzene [1].
In different countries, the production of benzene is
based on different processes. The main sources of
benzene production in Uzbekistan are pyrolysis
distillate produced by Uz-Kor Gas Chemical LLC JV and
reforming catalyst produced by Bukhara Oil Refinery
LLC.
One of the main points affecting the efficiency of the
extraction process is the efficiency of the extractant,
which determines the ratio of solvent to raw material.
Reducing this ratio is one of the promising ways to
improve the technical and economic indicators of the
process.
The literature [2,4] describes in detail the requirements
for selective solvents. An industrial extractant must
have high selectivity and dissolving ability, easy
regenerability, a sufficiently high density difference
with the raw materials being separated, low viscosity,
etc. When selecting an extractant, consideration
should be given to solvent resources and the ability of
the selected solvent to be used beyond extraction
processes and for other industrial purposes. Currently,
more than 200 solvents have been proposed for the
extraction of aromatic hydrocarbons, of which about
ten are used in industry. However, each of them, in
addition to positive technological characteristics, also
has a number of disadvantages. Therefore, research is
widely carried out in the field of synthesis of new
effective solvents and improvement of technology
based on existing extractants [5-9].
The most common extractant for C6
–
C8 aromatic
hydrocarbons is diethylene glycol, used in the Judex
process [5,6,7]. Its widespread use is explained by its
high selectivity, comparative cheapness, availability,
high thermal stability and low toxicity. Diethylene
glycol provides high recovery and purity of aromatic
hydrocarbons. The Yudex process has been intensively
improved by improving technology and replacing
diethylene glycol with higher polyglycols - tri- and
tetraethylene glycol, which have greater capacity
compared to diethylene glycol and almost the same
selectivity [2, 3, 4].
Sulfolane is one of the most effective modern selective
solvents, as evidenced by the rapid introduction of the
sulfolane process into industry abroad. So, if the first
installation was launched in 1962, then in 1970 the
process was already used in 40 installations.
Disadvantages of the process include difficulties in
removing solvent from separation products and the
need to use reduced pressure when regenerating the
solvent. Sulfolane has a relatively high melting point
(27.8°C) [l0], which can be reduced by adding water,
but this leads to a significant decrease in the solubility
of sulfolane. Dramatic changes in process conditions
compared to the Yudex process and the relatively high
cost of sulfolane require significant investment.
The French Petroleum Institute proposed using
dimethyl sulfoxide as an extractant. Its main
advantages
as
an
extractant
for
aromatic
hydrocarbons are as follows: due to the low viscosity
of the solvent, a fairly low melting point with a low
Volume 03 Issue 11-2023
190
International Journal of Pedagogics
(ISSN
–
2771-2281)
VOLUME
03
ISSUE
11
P
AGES
:
188-194
SJIF
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FACTOR
(2021:
5.
705
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(2022:
5.
705
)
(2023:
6.
676
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
water content and a fairly high density, the process can
be carried out at low temperatures of 25-40°C; under
process conditions, the solvent does not cause
corrosion of equipment; non-toxic; allows the isolation
of aromatic hydrocarbons from any oil fractions [7-8].
The disadvantages of dimethyl sulfoxide include the
fact that it has relatively low thermal stability (heat
resistant up to 140°C), which makes its regeneration by
rectification difficult. To obtain pure aromatic
hydrocarbons, a second solvent (butane or pentane) is
fed down the extraction column to displace 3-5% of
non-aromatic hydrocarbons from the extract phase [8-
9]. The solvent is separated from the extract phase by
re-extracting aromatic hydrocarbons with butane or
pentane. The use of a second solvent complicates the
technological scheme [10]. In addition, dimethyl
sulfoxide is hygroscopic, and the presence of water in
the solvent reduces its dissolving ability.
Thus, none of the selective solvents discussed above is
ideal for isolating low molecular weight aromatic
hydrocarbons. These disadvantages of solvents in
technological and economic terms force researchers to
search for new, more effective solvents, including
mixed ones, obtained from substances already
available in the chemical industry [30].
The most widely practiced is the addition of water [9,
10], in order to increase the selectivity of the extraction
process and increase the concentration of extracted
components in the extract. However, the use of water
leads to an increase in solvent consumption, a
decrease in its dissolving ability, and an increase in
energy costs. The introduction of water into the
extractant is accompanied in some cases by hydrolysis
of the solvent, leading to corrosion of the equipment
and a decrease in the stability of the solvent.
Modern researchers believe that the use of mixed
solvents that do not contain water is one of the
promising ways to improve the extraction process of
low molecular weight aromatic hydrocarbons.
The above literature review allows us to draw the
following conclusions. Currently, in industrial practice,
the liquid extraction process using selective solvents
has become widespread in industrial practice for the
extraction of low molecular weight aromatic
hydrocarbons
from
petroleum
feedstocks.
Improvement of the process is associated with the
selection of new selective solvents that are more
effective than those currently used. An analysis of the
literature shows that among the new selective
solvents currently proposed, dimethyl sulfoxide and
diethylene glycol are of practical interest. Benzene
extraction with DMSO + DEG system can be carried out
at low temperatures, atmospheric pressure and low
ratio of solvent to raw material. DMSO+DEG meets the
requirements for selective solvents and has a cheap
and accessible raw material base.
Experimental part. The purpose of the work is to study
the possibility of increasing the efficiency of the
process of benzene extraction from pyrolysis distillate
produced by JV Uz-Kor Gas Chemical LLC and
reforming catalysts produced by Bukhara Oil Refinery
LLC by using dimethyl sulfoxide (DMSO) and its
mixtures with diethylene glycol (DEG) as an extractant.
To achieve this goal, the following tasks are required:
1. Study of the mutual solubility of aromatic
hydrocarbons, n-paraffins, benzene and the mixed
solvent DMSO + DEG.
2. Study of the influence of the main process factors on
benzene extraction performance.
Volume 03 Issue 11-2023
191
International Journal of Pedagogics
(ISSN
–
2771-2281)
VOLUME
03
ISSUE
11
P
AGES
:
188-194
SJIF
I
MPACT
FACTOR
(2021:
5.
705
)
(2022:
5.
705
)
(2023:
6.
676
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
The scientific work investigated the dissolving and
selective abilities of the mixed solvent DMSO + DEG
during the extraction of benzene from an artificial
hydrocarbon mixture and pyrolysis distillate. The
relationships between extraction indicators and
technological parameters have been established.
Table 1. Physicochemical properties of DMSO
№ Indicator name
Reference data
1.
Molecular weight, g/mol
78,13
2.
Density, g/cm3
1,1004 g/sm³
3.
Boiling point, °C (at 760 mm Hg)
189
4.
Melting temperature,°С
18,5
5.
Acid dissociation constant pKa
35,1
6.
Dynamic viscosity at 25°C, Pa s
0,001996
7.
Refractive index of dimethyl sulfoxide at 20°C:
1,4778-1,4790
To determine the mutual solubility of dimethyl
sulfoxide and n-paraffins, n-hexane n-paraffins and n-
octane were used. For the work, we used DMSO, DEG,
benzene and n-paraffins, the physicochemical
constants of which corresponded to the literature data
(Tables 1
–
2).
Dimethyl sulfoxide (DMSO) is a chemical substance
with the formula
–
(CH3)2SO. A colorless, odorless
liquid with a specific sweetish taste (an insufficiently
pure product has a characteristic odor of dimethyl
sulfide). An important bipolar aprotic solvent. It is
widely used in various fields of chemistry, as well as as
a medicine [4].
Table 2. Physicochemical properties of DEG
№ Indicator name
Reference data
1.
Molecular weight, g/mol
106,12
2.
Density, g/cm3
1,118
3.
Boiling point, °C (at 760 mm Hg)
244-245
4.
Melting point, °C
-7.8
5.
Flash point, °C
124
The system containing pure DMSO is characterized by
a small area of the heterogeneous region, which
indicates the high mutual solubility of the components
of the system, the high dissolving ability and low
selective ability of DMSO.
Thus, the addition of DEG to DMSO leads to a decrease
in solubility and an increase in solvent selectivity. Given
the nature of the solubility curves, the content of DEG
in a mixed solvent above 50% is impractical.
Volume 03 Issue 11-2023
192
International Journal of Pedagogics
(ISSN
–
2771-2281)
VOLUME
03
ISSUE
11
P
AGES
:
188-194
SJIF
I
MPACT
FACTOR
(2021:
5.
705
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(2022:
5.
705
)
(2023:
6.
676
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
According to the above optimal technology condition,
benzene was extracted from the pyrolysis distillate
produced by JV Uz-Kor Gas Chemical LLC in a mixed
solvent DMSO + DEG in a mass ratio of 1:1 and the
resulting benzene was purified and analyzed on a
GCMS device.
Fig.2. Chromatogram of extracted benzene from pyrolysis distillate.
The obtained analysis results show that the extraction
of benzene from the pyrolysis distillate produced by JV
Uz-Kor Gas Chemical LLC in a mixed solvent DMSO +
DEG in a mass ratio of 1:1 benzene appeared in 1.660
and 1.790 minutes with a purity of 97.52%.
Fig.3. IR spectrogram of extracted benzene from pyrolysis distillate
0 . 5 0
1 . 0 0
1 . 5 0
2 . 0 0
2 . 5 0
3 . 0 0
3 . 5 0
4 . 0 0
4 . 5 0
5 . 0 0
5 . 5 0
1 e + 0 7
2 e + 0 7
3 e + 0 7
4 e + 0 7
5 e + 0 7
6 e + 0 7
7 e + 0 7
8 e + 0 7
9 e + 0 7
1 e + 0 8
1 . 1 e + 0 8
1 . 2 e + 0 8
1 . 3 e + 0 8
1 . 4 e + 0 8
1 . 5 e + 0 8
1 . 6 e + 0 8
1 . 7 e + 0 8
1 . 8 e + 0 8
1 . 9 e + 0 8
2 e + 0 8
2 . 1 e + 0 8
T im e -->
A b u n d a n c e
T I C : 3 1 1 0 2 2 o b b 1 -D A . D \ d a t a . c d f
0 . 8 7 9
1 . 2 9 8
1 . 6 6 0
1 . 7 9 0
2 . 9 5 0
5 . 0 6 6
C:\Users\BRUKER\Documents\Bruker\OPUS_8.7.10\DATA\MEAS\OK-BENZ.1 OK-BENZ Instrument type and / or accessory
11/10/2022
30
91
.9
5
30
72
.2
0
30
36
.9
3
29
56
.8
8
29
24
.0
9
28
72
.1
9
28
54
.8
9
27
31
.4
2
19
56
.0
4
18
11
.0
3
15
22
.6
9
14
78
.7
7
14
67
.1
5
13
78
.0
3
13
40
.8
7
10
35
.7
4
76
5.
00
72
2.
10
67
0.
85
500
1000
1500
2000
2500
3000
3500
Wavenumber cm-1
0.
3
0.
4
0.
5
0.
6
0.
7
0.
8
0.
9
1.
0
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Volume 03 Issue 11-2023
193
International Journal of Pedagogics
(ISSN
–
2771-2281)
VOLUME
03
ISSUE
11
P
AGES
:
188-194
SJIF
I
MPACT
FACTOR
(2021:
5.
705
)
(2022:
5.
705
)
(2023:
6.
676
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
Fig.4. IR spectrogram of extracted benzene from pyrolysis distillate compared with the instrument database.
CONCLUSIONS
Based on the results obtained, the extraction of
benzene from the pyrolysis distillate produced by JV
Uz-Kor Gas Chemical LLC in a mixed solvent DMSO +
DEG in a mass ratio of 1:1 makes it possible to increase
the efficiency of the benzene extraction process
expediently.
The optimal parameters of the benzene extraction
process with a mixed solvent DMSO + DEG, necessary
for the design of installations for the extraction of
aromatic hydrocarbons, have been determined.
Based on the data obtained and their mathematical
processing in laboratory conditions, optimal conditions
for the extraction of benzene from model mixtures of
hydrocarbons and pyrolysis distillate with a mixed
solvent DMSO + DEG were established. The feasibility
and effectiveness of replacing diethylene glycol with a
mixed solvent DMSO + DEG was shown. The data
obtained can be used in the design of installations for
the extraction separation of benzene and the
reconstruction of similar installations.
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Volume 03 Issue 11-2023
194
International Journal of Pedagogics
(ISSN
–
2771-2281)
VOLUME
03
ISSUE
11
P
AGES
:
188-194
SJIF
I
MPACT
FACTOR
(2021:
5.
705
)
(2022:
5.
705
)
(2023:
6.
676
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
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Джураева
Лайло
Рахматуллаевна
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ассистент кафедры «Химия» Бухарского
инженерно
-
технологического института, Е
-
mail berdiyevaz@mail.ru Тел:91
- 449-41-31
