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RESULTS AND DISCUSSION
The results of the BET method and chromatographic determination of the specific surface area of
the catalysts and their composition are presented in Table 1 below.
TABLE 1. THE COMPOSITION OF CATALYSTS AND THEIR SPECIFIC SURFACE
AREA
Catalyst Catalyst composition
Method of preparation
S
col,
m
2
/g
1
(MoO
3
)
x
∙
(ZnO)
y
∙
(ZrO
2
)
z
Swallowing together
258
2
(MoO
3
)
x
∙
(ZnO)
y
∙
(B
2
O
3
)
z
Swallowing together
280
3
(MoO
3
)
x
∙
(B
2
O
3
)
y
∙
(ZrO
2
)
z
Swallowing together
323
4
(MoO
3
)
x
∙
(ZnO)
y
∙
(ZrO
2
)
z
∙
(B
2
O
3
)
k
Swallowing together
257
ISSN: 2278-4853 Vol 10, Issue 9, September, 2021 Impact Factor: SJIF 2021 = 7.699
Asian Journal of Multidimensional Research (AJMR)
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From the data given in Table 2, it can be seen that in the products of processing of C
1
-C
4
-
hydrocarbons in catalysts containing (MoO
3
)
x
∙
(ZnO)
y
∙
(ZrO
2
)
z
are aromatic hydrocarbons -
benzene, toluene, ethylbenzene, xylenes (in the liquid phase). ) and the gas phase contains C
1
-C
4
-
hydrocarbons as well as hydrogen.
TABLE 2. RESULTS OF CATALYTIC TRANSFORMATION OF C
1
-C
4
ALKANES IN
CATALYSTS (MOO
3
)
X
∙
(ZNO)
Y
∙
(ZRO
2
)
Z
T,
℃
550
600
650
Conversion,%
71,2
78,5
82,4
Liquid phase yield,%
18,5
24,8
30,2
Selectivity
with
respect to ArU,%
26
31,6
36,7
Liquid phase (catalyst) composition, mass.%
Benzene
31,2
45,8
48,7
Toluene
37,6
34,3
32,6
Ethylbenzene
18,4
11,5
11,8
Xylenes
12,8
8,4
6,9
Table 2 shows that as the temperature rises from 550 6 to 650
℃
, the conversion of C
1
-C
4
-
alkanes and selectivity for aromatic hydrocarbons increases.Under similar conditions, the amount
of benzene in the liquid phase increases.The amount of toluene and xylenes decreases. Table 3
shows the results of the catalytic conversion of C
1
-C
4
-alkanes in the catalyst
(MoO
3
)
x
∙
(ZnO)
y
∙
(B
2
O
3
)
z
.
TABLE 3. RESULTS OF CATALYTIC TRANSFORMATION OF C
1
-C
4
-ALKANES IN
THE CATALYST (MOO
3
)
X
∙
(ZNO)
Y
∙
(B
2
O
3
)
Z
T,
℃
550
600
650
Conversion,%
68,5
73,8
79,7
Liquid phase yield,%
14,3
19,5
25,6
Selectivity
with
respect to ArU,%
20,9
26,4
32,1
Liquid phase (catalyst) composition, mass.%
Benzene
31,2
37,9
41,2
Toluene
42,8
47,8
48,3
Ethylbenzene
19,4
10,1
8,2
Xylenes
6,8
4,2
2,3
Table 3 also shows similar data for the above catalyst. Table 4 shows the results of the catalytic
conversion of C
1
-C
4
-alkanes in the catalyst (MoO
3
)
x
∙
(ZnO)
y
∙
(ZrO
2
)
z
∙
(B
2
O
3
)
k
.
ISSN: 2278-4853 Vol 10, Issue 9, September, 2021 Impact Factor: SJIF 2021 = 7.699
Asian Journal of Multidimensional Research (AJMR)
https://www.tarj.in
347
AJMR
TABLE 4. RESULTS OF CATALYTIC TRANSFORMATION OF C
1
-C
4
-ALKANES IN
THE CATALYST (MOO
3
)
X
∙
(ZNO)
Y
∙
(ZRO
2
)
Z
T,
℃
550
600
650
Conversion,%
75,2
79,8
86,7
Liquid
phase
yield,%
36,4
43,5
49,9
Selectivity
with
respect to ArU,%
48,4
54,5
57,6
Liquid phase (catalyst) composition, mass.%
Benzene
18,1
32,7
40,4
Toluene
46,2
40,8
44,7
Ethylbenzene
20,7
14,4
8,6
Xylenes
15
12,1
6,3
As can be seen from Table 4, the yield and selectivity of aromatic hydrocarbons are 36.4% and
48.4%, respectively, at 550
℃
. As the temperature rises from 550 6 to 650
℃
, the yield and
selectivity of aromatic hydrocarbons increase from 36.4% to 49.9% and the selectivity from
48.4% to 57.6%, respectively. The chemical composition of the samples obtained during the
catalytic conversion of C
1
-C
4
-hydrocarbons to aromatic hydrocarbons shows that in this process,
catalysts with (MoO
3
)
x
∙
(ZnO)
y
∙
(ZrO
2
)
z
and (MoO
3
)
x
∙
(ZnO)
y
∙
(ZrO
2
)
z
∙
(B
2
O
3
)
k
have high catalytic
activity. The analysis of the obtained results shows that under the same conditions (at 650
℃
) the
maximum yield of aromatic hydrocarbons (MoO
3
)
x
∙
(ZnO)
y
∙
(ZrO
2
)
z
∙
(B
2
O
3
)
k
is observed in the
catalyst. Maximum conversion (75.2%) was observed in №4 catalyst during the first 4 hours of
catalyst operation. When the catalyst was operated for 5 hours, a sharp decrease in C
1
-C
4
-
hydrocarbon conversion was observed, after which the decrease in conversion rate slowed down.
Conver
sion
,%
АрУ yie
ld
, %
Reaction time, min
Reaction time, min
Figure 1. Conversion of C
1
-C
4
-hydrocarbons in catalyst №4 and the
dependence of the yield of aromatic hydrocarbons on the reaction time
The yield of aromatic hydrocarbons in №4 catalyst (36.4%) was observed during the first 4 hours
of catalyst operation. After 5 hours of operation of the catalyst, the yield of aromatic
ISSN: 2278-4853 Vol 10, Issue 9, September, 2021 Impact Factor: SJIF 2021 = 7.699
Asian Journal of Multidimensional Research (AJMR)
https://www.tarj.in
348
AJMR
hydrocarbons decreased. The degree of conversion of C
1
-C
4
-alkanes in the presence of these
catalysts and the composition of the formed compounds depends on the process temperature and
the nature of the components in the catalytic system. The composition of the products formed
during the processing of C
1
-C
4
-alkanes in the above-mentioned catalysts shows that the catalysts
are multifunctional, and several reactions are observed in the created zeolite-containing catalysts:
cracking, dehydrogenation, isomerization, dehydrogenation, alkylation.
Figure 2. Temperature dependence of product selectivity
The distribution of pores in the catalyst №4 by specific surface area and size was determined by
low-temperature desorption of nitrogen. The calculation of the reference surface area was
performed by the BET method. According to the data, №4 catalyst has a highly developed
surface. The surface value is 257 m
2
/g at №4 catalyst and 258 m
2
/g at catalyst №1. The
distribution of pores by size in the catalysts being tested is given in Table 5 below.
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