The use of the model of kinetics of ethylbenzene dehydrogenation to estimate the state variables and catalyst performance under unsteady conditions

Abstract

The article considers the application of the mathematical modeling method to describe the dynamics of the catalytic layer state variables of the styrene production reactor. This method was carried out using a kinetic approach for description of chemical transformations, which occurs in a multicomponent gas mixture. The main physical processes, affecting the decrease in catalytic activity during operation, are considered and the relationship between them is described. A method for increasing the efficiency of the catalytic system in terms of ACS (automated controlling system) synthesis is proposed. The mathematical formulation of the problem of creating a predictive program control system under unsteady conditions is completed. Mathematical software has been developed that allows us to evaluate activity and predict the dynamics of changes in such production efficiency indicators as ethylbenzene conversion and styrene selectivity. In that framework, the blocking of catalyst active centers, proceeding by the sequential mechanism of coke formation, is classified as a deactivating factor. The distribution patterns of carbon along the length of the reaction space at different times of the catalyst inter-reactivation period, depending on changes in the mixture component concentrations and the temperature condition, are revealed. Based on the production data, the calculation and approximation of raw materials conversion values and selectivity for the target product were carried out taking into account the accumulation of carbon on the layer surface, as well as the variation of process parameters such as temperature, pressure of the reaction mixture and partial pressures of the components.