Acumen:
International Journal of
Multidisciplinary Research
Volume 1, Issue 2
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Acumen: International Journal of Multidisciplinary Research
RESEARCH OF THE SYNTHESIS PROCESS OF ALIPHATIC
HYDROCARBONS WITH THE PARTICIPATION OF A CO-CATALYST
FROM SYNTHESIS GAS
Nematov Khusan Ibodullayevich
PhD, Karshi engineering-economics institute
ИССЛЕДОВАНИЕ ПРОЦЕССА СИНТЕЗА АЛИФАТИЧЕСКИХ
УГЛЕВОДОРОДОВ С УЧАСТИЕМ СОКАТАЛИЗАТОРА ИЗ СИНТЕЗ-
ГАЗА
Нематов Хусан Ибодуллаевич
к.т.н. Каршинский инженерно-экономический институт
ABSTRACT:
In this article, the characteristics of the synthesis of
hydrocarbons from CO and H
2
in the presence of catalysts containing Co coated with
alkali metals were studied, the results of the study of the catalytic effect of aluminum
oxides and aluminosilicates of different porosity were presented, the liquid synthesis
products for the sample based on aluminum oxide selectivity increased from 41 to 92%
when potassium catalyst was added, selectivity of methane formation decreased from
29 to 4%, the effect of the nature of the support (A
2
O
3
and SiO
2
) and 20Co/ The addition
of potassium to the SiO
2
sample did not change the CO conversion by 86-87%, but
increased the yield of C
5+
hydrocarbons and their selectivity:
KEY WORDS:
Aluminum oxide, catalyst, Co-K catalyst, Fischer-Tropsch,
aliphatic hydrocarbons, Liquid hydrocarbons, CO conversion, Co-catalyst.
АННОТАЦИЯ:
В статье изучены особенности синтеза углеводородов из
СО и Н
2
в присутствии катализаторов, содержащих Со, покрытых щелочными
металлами, представлены результаты изучения каталитического действия
оксидов алюминия и алюмосиликатов различной пористости.селективность
образования метана с 29 до 4%, влияние природы носителя (A
2
O
3
и SiO
2
) и 20Co/
Добавление калия в образец SiO
2
не изменило конверсию СО на 86-87%, но
увеличило выход углеводородов С
5+
и их селективность:
КЛЮЧЕВЫЕ СЛОВА:
оксид алюминия, катализатор, Co-K катализатор,
Фишера-Тропша, алифатические углеводороды, жидкие углеводороды,
конверсия CO, сокатализатор.
In recent years, the demand for catalysts has been increasing, nowadays almost
all catalysts and sorbents are imported. Catalysts containing especially Co are one of
Acumen:
International Journal of
Multidisciplinary Research
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Acumen: International Journal of Multidisciplinary Research
the main catalysts of the process for obtaining aliphatic hydrocarbons from synthesis
gas [1].
In recent years, the demand for petroleum products has increased due to the
dwindling reserves of oil, which is why synthetic fuels are obtained from gas and coal
as a result of research. By obtaining aliphatic hydrocarbons through the Fischer-
Tropsch synthesis, fuels, polymer products and organic solvents are mainly obtained,
and taking into account the need for these products, the study of new catalytic
properties of Co-containing catalysts and the localization of these catalysts is one of
the current problems [ 2].
Currently, hydrocarbon Fe- and Co-catalysts are used in industry to obtain
aliphatic mixture from CO and H
2
. Co-containing catalysts of the Fischer-Tropsch
synthesis increase the yield of alkanes as a result of the reaction.
Co catalyst to increase the amount of high molecular hydrocarbons and reduce
the concentration of gaseous products is one of the important tasks in the development
of Fischer-Tropsch synthesis.
The introduction of alkali metals into the Co catalyst increases the average
molecular weight of hydrocarbons and reduces methane production [3].
Cobalt catalysts are active in the synthesis of hydrocarbons from CO and H
2
at
temperatures of 150 - 240 °C. As the temperature increases, their activity and
selectivity change. An increase in temperature leads to an increase in CO conversion
and an increase in the yield of synthesis products. If the total yield of C1-C4 and CO2
hydrocarbons increases with increasing temperature, the yield of liquid hydrocarbons
will exceed the maximum corresponding to the optimum temperature for obtaining
these products. The selectivity of the catalyst for liquid hydrocarbons decreases with
increasing temperature.
Temperature equally affects the main indicators of the process of synthesis of
hydrocarbons from CO and H
2
. The optimal synthesis temperature is their individual
characteristic and is determined by the composition of the catalyst, as well as the
conditions of its preliminary purification. The results of studying the influence of the
nature of a wide variety of supports (alumina oxides and aluminosilicates of different
porosity) on the properties of cobalt systems in the synthesis of hydrocarbons from CO
and H
2
are presented [4].
Table 1
Synthesis of hydrocarbons from CO and H
2
in Co/carrier catalysts T=190 °С,
R=1 atm
catalyst
X
CO
%
Output g/m
3
Selectivity %
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International Journal of
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Сo/А1
2
O
З
(1)
47
6
4
87
3
5
4
90
1
Сo/А1
2
O
З
(2)
58
15
10
96
4
11
8
80
1
Сo/А1
2
O
З
(3)
67
19
17
104
4
12
12
75
1
Сo/А1
2
O
З
(4)
51
17
14
76
3
14
13
72
1
Co/ Ac(1)
16
2
2
29
2
5
5
88
2
Co/ Ac(2)
23
2
1
43
3
4
3
91
2
Co/ Ac(3)
22
3
2
40
1
6
5
88
1
Co/ Ac(4)
30
5
5
52
2
7
8
84
1
Co/ Ac(5)
34
6
7
58
0
8
9
83
0
In the studied series of catalysts for 10 Co/AC(1-5) samples, high selectivity
for target synthesis products (83-91%), their low yield (29-58 g/m
3
) and low CO
conversion of 16-34% were observed.
10Co/Al
2
O
3
(1-4) systems showed high activity: XCO 51-67%, the yield of
liquid hydrocarbons was 76-104 g/m
3
, therefore, the study of the properties of Co-
catalysts in the synthesis of hydrocarbons 1 from CO and H
2
-4 was carried out in the
presence of samples prepared on the basis of Al
2
O
3
with structural properties similar to
supports. (Table 1) Properties of Co-system catalysts prepared on the basis of SiO
2
for
Fischer-Tropsch. Fischer-Tropsch synthesis catalysts were also studied. To increase the
activity of the catalyst, the amount of cobalt in Co/Al
2
O
3
and Co/SiO
2
samples was
increased to 20%.
We studied the influence of the nature of the support (Al
2
O
3
and SiO
2
) on the properties
of 20Co-1K / Al
2
O
3
and 20Co-1SiO
2
catalysts. Comparison of this series of samples at
a synthesis temperature of 200°C showed that the addition of 1% potassium resulted in
a significant decrease in CO conversion for the alumina-based Co-system: from 94 to
67% (Figure 1).
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Figure 1. Effect of catalyst nature on CO conversion of 20Co(0-1)K/Al
2
O
3
(SiO
2
) and
yield of C
5+
product in hydrocarbon synthesis from CO and H
2
at T=200 °C.
Figure 2. Effect of 20Co(0-1)K/Al
2
O
3
(SiO
2
) catalyst on the selectivity of C
5+
and CH
4
in the synthesis of hydrocarbons from CO and H
2
at T=200°C.
Productivity of liquid products increased from 80 to 127 g/m
3
at the same time
as hydrocarbon chain growth probability α increased sharply from 0.68 to 0.91. The
addition of potassium to the 20Co/SiO
2
catalyst resulted in a reduction of Xco from 72
to 66%, while the yield of liquid hydrocarbons decreased from 131 to 120 g/m
3
.
For the sample based on aluminum oxide, the selectivity of liquid synthesis
products decreased from 41 to 92% with the addition of a potassium catalyst, and the
selectivity of methane formation decreased from 29 to 4% (Fig. 2). The addition of
potassium to the 20Co/SiO
2
catalyst did not change these selectivity indicators, which
were 87-88% and 5%, respectively.
Comparison of these catalysts at the optimal synthesis temperature showed that
the introduction of 1% K into the Co-systems led to a different increase in the activity
94
72
67
66
0
20
40
60
80
100
Al2O3
SiO2
CO,%
Taqdim qilinmagan namuna
Taqdim qilingan namuna
80
131
127
120
0
50
100
150
Al2O3
SiO2
C5++(g/m3)
Taqdim qilinmagan namuna
Taqdim qilingan namuna
41
88
92
87
0
20
40
60
80
100
Al2O3
SiO2
C5++,%
Taqdim qilinmagan namuna
Taqdim qilingan namuna
29
5
4
5
0
10
20
30
40
Al2O3
SiO2
CH4,%
Taqdim qilinmagan namuna
Taqdim qilingan namuna
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International Journal of
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of the catalysts (Table 2). The addition of potassium to the alumina-based Co-catalyst
helped to increase the conversion of CO from 72 to 82%, while increasing the liquid
synthesis products from 112 to 138 g / m
3
and the selectivity of their formation from
75 to 81 %.
Table 2
Synthesis of hydrocarbons from CO and H
2
in the presence of 20Co-(0-1)M
sitell catalysts. CO / H
2
= 1: 2, P = 0.1 Mpa
Catalyst
°C
X
CO
%
Output g/m
3
Selectivity %
а
CH
4
C
2
-
C
4
C
5+
CO
2
C
5+
CH
4
C
2
-C
4
CO
2
Co/Al
2
O
3
190 72
20
15 112 17
75
12
9
4
0.86
Co-
1K/Al
2
O
3
210 82
16
10 138 24
81
8
6
5
0.87
Co/SiO
2
210 86
18
17 140 21
79
9
9
4
0.83
Co-1K/
SiO
2
220 87
13
14 147 24
82
6
7
4
0.82
The addition of potassium to the 20Co/SiO
2
sample did not change the CO
conversion by 86-87%. The yield of C
5+
hydrocarbons and their selectivity increased
slightly: from 140 to 147 g/m
3
and from 79 to 82%, respectively. C
1
-C
4
hydrocarbon
emissions decreased from 35 to 26-27 g/m
3
for the catalysts on both supports. An
increase of 10-20 °C in the optimal synthesis temperature was observed for all samples.
For the first time, activation of Co-catalyst with metals of group I (Li, Na, K,
Rb, Cs) was found to increase the yield of liquid hydrocarbons and increase their
average molecular weight in Fischer-Tropsch synthesis. A correlation was established
between the catalytic activity and selectivity of the nature of the alkali metal 20So-
M/A1
2
O
3
(SiO
2
). The method of preparation of the catalyst is based on the sequence of
impregnation of active metals and increases the efficiency of synthesis of hydrocarbons
from CO and H
2
in the process, the conversion of CO and the formation of high C
5+
products.
For Fischer-Tropsch synthesis, a Co-K catalyst was adopted, which allows the
selection of liquid hydrocarbons with a synthesis gas output of up to 138 g/nm3. In this
case, the resulting hydrocarbons are enriched with heavy fractions:
In summary, as a result of the research conducted, the synthesis of
hydrocarbons from CO and H
2
on Co/carrier catalysts was studied for 10Co/AC(1-5)
samples, and the selectivity of liquid synthesis products for the aluminum oxide-based
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International Journal of
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Acumen: International Journal of Multidisciplinary Research
sample with the addition of a potassium catalyst 41 to 92%, the selectivity of methane
formation was found to decrease from 29 to 4%.
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