Search

H2SO4-catalysed isobutane alkylation with alkenes is an important industrial process used to obtain high-octane alkylate. In this process, the concentration of H2SO4 is one of the main parameters. For alkylation, sulphuric acid containing 88%–98% monohydrate is typically used. However, only a H2SO4 concentration of 95%–96% enables alkylate with the maximum octane number to be obtained. Changes in H2SO4 concentration due to decontamination are the main cause of process variations. Therefore, it is necessary to maintain the reactor acid concentration at a constant level by regulating the supply of fresh catalyst and pumping out any spent acid. The main reasons for the decrease in the H2SO4 concentration are accumulation of high-molecular organic compounds and dilution by water. One way to improve and predict unsteady alkylation processes is to develop a mathematical model that considers catalyst deactivation. In the present work, the formation reactions of undesired substances were used in the description of the alkylation process, indicating the sensitivity of the prediction to H2SO4 activity variations. This was used for calculation the optimal technological modes ensuring the maximum selectivity and stability of the chemical–technological system under varying hydrocarbon feedstock compositions.

H2SO4-catalysed isobutane alkylation with alkenes is an important industrial process used to obtain high-octane alkylate. In this process, the concentration of H2SO4 is one of the main parameters. For alkylation, sulphuric acid containing 88%-98% monohydrate is typically used. However, only a H2SO4 concentration of 95%-96% enables alkylate with the maximum octane number to be obtained. Changes in H2SO4 concentration due to decontamination are the main cause of process variations. Therefore, it is necessary to maintain the reactor acid concentration at a constant level by regulating the supply of fresh catalyst and pumping out any spent acid. The main reasons for the decrease in the H2SO4 concentration are accumulation of high-molecular organic compounds and dilution by water. One way to improve and predict unsteady alkylation processes is to develop a mathematical model that considers catalyst deactivation. In the present work, the formation reactions of undesired substances were used in the description of the alkylation process, indicating the sensitivity of the prediction to H2SO4 activity variations. This was used for calculation the optimal technological modes ensuring the maximum selectivity and stability of the chemical-technological system under varying hydrocarbon feedstock compositions. [ABSTRACT FROM AUTHOR]

In this research, the indicators of the H2SO4-catalyzed benzene alkylation with alkenes were performed with use of the mathematical model, which was implemented in the industry at one of the refineries. We present the effect of the butane-butylene fraction flow rate and the isobutane concentration in the feedstock on the content of isooctane's in the alkylate. The possibility of using a mathematical model of the process of H2SO4-catalyzed benzene alkylation with alkenes as a training system has been shown. This will allow the oil refinery technologists to gain theoretical skills to troubleshoot industrial plants and to optimize their performance. [ABSTRACT FROM AUTHOR]

In the paper, translation-invariant Gibbs measures for the Blum-Kapel model on a Cayley tree of order k are considered. An approximate critical temperature Tcr is found such that for T ≥ Tcr there exists a unique translation-invariant Gibbs measure and for 0 < T < Tcr there are exactly three translation-invariant Gibbs measures. In addition, the problem of (not) extremality for the unique Gibbs measure is studied. [ABSTRACT FROM AUTHOR]