CC BY
0УДК 62 Huseynov A., Alasgarova T.
Huseynov A.
Azerbaijan State University of Oil and Industry (Baku, Azerbaijan)
Alasgarova T.
Azerbaijan State University of Oil and Industry (Baku, Azerbaijan)
STUDY OF PROPYLENE CONVERSION PROCESS WITH THE PARTICIPATION OF V, CR, P, CU OXIDE ELEMENTS IN A DIRECT FLOW REACTOR
Аннотация: in the world and at the same time in the Republic of Azerbaijan, the processes of complex processing of oil-plant hydrocarbon gases and the oxidation and conversion of these gases with the participation of heterogeneous catalysts of various types have been relevant and remain relevant at present. Effective use of these gases will ensure the use of hydrocarbon gases emittedfrom oil refineries, and also reduce the demand for natural resources. Although ARDNS and other related institutions have recently implemented many projects related to this problem, it has not yet been resolved. One of the main reasons for these shortcomings is the lack of systematic research in the direction of the processing of oil-plant hydrocarbon gases, and the fact that scientific research is of a small nature.
Ключевые слова: propylene, oxidation, conversion, acrolein.
introduction. As a result of the conducted research, the process of converting propylene with the presence of active heterogeneous catalysts was studied. The study of the propylene conversion process of the catalysts synthesized in the direct flow reactor at different temperatures was carried out, and the degree of propylene conversion, optimal temperature conditions and contact time were studied.
In the process with an optimal temperature regime of 500 C and a contact time of 3.0 seconds, the conversion rate of propylene was 58-60%.
We used 3 reactors to carry out the process of converting propylene with the participation of synthesized catalysts [1-3].
First, we used fixed bed catalysts in a stationary reactor. In a stationary reactor, the experiment was carried out in the temperature range of 450,500 and 550 C, with a contact time of 1-3 seconds. Thus, at a temperature of450 C, with a contact time of 3.0 seconds, the yield of C was 8.4%, and the selectivity was 18.5%.
At that time, the conversion rate was 45.0%. At a temperature of 500 C, the degree of conversion increased to 58%, and the selectivity was 33.0%, and the product yield was 19.2%. When considering the yields and selectivities of these products from the point of view of the molecular mass (from C1 to C6) of the products obtained at the temperature of 500 C, no regularity is visible. At 500 and 550 C, the numbers change sinusoidally. An exceptional case is that when the process is carried out at 500 C, C6 is formed as a by-product, the yield of which is 11.4%, and the selectivity is
Еxperimental part. Propylene conversion was carried out under the same conditions but at 55C, and the propylene conversion slightly increased to 60%. At this time, the minimum yield and selectivity occurred at C4, that is, the yield was 2.7%, and the selectivity was 4.5%.
19.5%.
Out %
о
450
Figure 1. Shows the dependence of the product yield on the contact time for a stationary reactor.
As you can see, the obtained curves have the same character, that is, they all pass through the maximum. Here, the curve obtained only for C1 is slightly different in nature. These studies carried out at 500 C showed that the yield values found for C2 stand out from the values of other products, i.e. they are slightly higher.
Here, when the contact time is 2 seconds, the maximum yield is 20.1%. The maximum price of the rest of the products except C2 during this contact period is 11.5%- not more than Almost all the curves have the same character and pass through the maximum.
Thus, the studies conducted in a stationary reactor showed that the optimal temperature for the process of propylene conversion with the presence of new types of heterogeneous catalysts in the catalyst volume of 5 cm3 was 500 C when the contact
time was 2 seconds at atmospheric pressure.
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гг. 20 IS 16. 14 13-lD 86 4
0
Figure 1.2. In the presence of V, Cr, P, Cu = 2.0: 1.5 : 1.0 : 1.5 catalysts, the dependence of the conversion rate of propylene on the active mass of the catalysts and the conversion rate of the product on the active mass of the catalysts was shown in the reactor at a temperature of 475 C.
The first experiments were conducted at a temperature of 450 C. At this time, the conversion rate of propylene was 54%. As you can see, the yields of the obtained products are characterized by different curves depending on the temperature. The
curves obtained for C2 and C5 products at 450 C temperature are parabolic in nature. The values of the curve constructed for C4 decrease with increasing temperature.
At that temperature, yields of C2 and C4 are higher than 19%. The yield for product C5 first increases, then decreases and is 3.2%. The hot catalyst was 475 C for subsequent experiments in a bed reactor. The obtained results showed that the conversion rate of propylene at this temperature is higher and is 68%. As the molecular mass of the products released at 475 C temperature increases, the output does not follow any regularity, the character of the curve becomes sinusoidal [3-4].
Here, compared to the stationary reactor, the yield of C6 is less and is 4.8%. The difference between the yields of products conducted at temperatures of 450 C and 475 C in the heated bed reactor is only for C5. Thus, the yield at 450 C was 3.2%, and at 475 C it was 16.7%. The subsequent processes were continued at a temperature of 500 C in a hot catalyst layered reactor.
As the molecular weight of the products obtained at this temperature increases from C1 to C6, the maximum yield value is 18.9%, but the nature of the curve changes sinusoidally. 500 C conversion rate of propylene was 70%.
Figure 1.3. The dependence curves of product yields in the hot catalyst layered
reactor on the contact time are shown.
%
t,°C
As you can see, all the described curves have a similar character and pass through the maximum. If we compare these curves with the curves obtained in the stationary reactor, we will see that they are of the same nature. Therefore, it is more appropriate to choose the experimental temperature of 475 C for hot catalyst bed reactors. Finally, the prepared heterogeneous catalysts were tested in direct flow reactors. The conditions for the propylene conversion process in a direct flow reactor are the same as in a stationary reactor. The difference is only in the temperature of the experiments, which was between 425-475 C for the direct flow reactor.
The first experiments were conducted at 425 C. At this time, the conversion rate of propylene was 60%. As can be seen from the graph, the maximum output of the obtained products occurs at 450 C. Here, the curve obtained for C6 plays an exceptional role, that is, the maximum value of the yield is obtained at a temperature of 10, 475 C. The highest yield belongs to C2 at 450 C, which is 20% [4-5].
It was found that with increasing temperature, the yield of C2, C5 and C6 products decreases, and the yield of C1 and C6 products increases. If we consider the nature of the curves, any regularity is not noticeable here. For example, while the output
%
22 .
Figure 1.4. Shows the graph of the temperature dependence of the yield of the obtained products.
curves for the obtained C2 and C5 products exceed the maximum, the characteristics of the curves for the C1 and C6 products are different, that is, their output increases in parallel with the increase in temperature. Unlike the obtained C4 product, the yield decreases with increasing temperature. The output of C4 from the products obtained at a temperature of 425 C was higher - 21.4%, and the lowest output belongs to C - 5%, and at a temperature of 475 C, the output of C2 - was higher - 17.8%, the minimum output was again Corresponds to C6, i.e. 10.2%. The degree of conversion of propylene at 450 C and 475 C was 68% and 70%, respectively.
Figure 1.5. The dependence curves of product yields during the conversion of propylene at 450 C in a direct flow reactor are shown.
As it can be seen, the characteristic of the curve obtained for C6 differs from the others, that is, as the contact time increases, its output also increases.
All the curves pass through the maximum, the character of the remaining curves being the same [6-8].
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7,0 х,я
%
4
425 450 475 t, *C
Figure 1.6. As can be seen from -, the maximum results are obtained when the contact time is t=6.0 seconds.
Conclusion. When the contact time t= 4 seconds, the lower and upper limits of the output are 4.3% and 15%, respectively. The yield varies from 7% to 18% when the contact time t= 6.5 seconds.
From the experiments conducted and the results obtained, it can be concluded that the best result was obtained in the direct flow reactor in the process of converting propylene with the presence of V:Cr:P:Cu = 2.0:1.5:1.0:1.5 catalysts.
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