The author of the article presents a mathematical description of the process of catalytic cracking, formulas for calculating kinetic parameters: concentration and activation energy. For their solution, the direct problem the Runge-Kutta method was applied. A genetic algorithm was used to find the minimum of the function. The optimization problem was formulated, criteria for multi-criteria optimization were selected: the output of the target product (gasoline), the maximum amount of high-octane components (isoparaffins and aromatic hydrocarbons), minimization of aromatic and olefin hydrocarbons. Possible combinations of Pareto front optimality criteria are presented. Variable parameters are reaction temperature and reaction time. The solution of the multi-criteria optimization problem is given. An increase in the yield of gasoline and at the same time the content of high-octane components in it is observed with an increase in the reaction temperature and a decrease in reaction time. Minimizing the output of olefins while maximizing the output of gasoline is also observed with an increase in temperature and a decrease in reaction time. Thus, in order to increase the yield and quality of catalytic cracking gasoline, one should strive to maximize the reaction temperature, in this case it is 600 °С, and reduce the reaction time to tenths of seconds, which requires the use of sophisticated equipment and high precision process control. These trends are present in the modern development of the process.

This article presents a 16-lump model of catalytic cracking of vacuum gasoil, which allows to take into account the quantity and quality of the main products of the process: gasoline, propane-propylene and butane-butylene fractions; and by-products of the process: light and heavy catalytic gasoil. To solve the direct problem of solving a system of differential equations, the Runge-Kutta method of order 4 is used, to solve the inverse problem of choosing the constants of the rate of chemical transformations, the method of direct search for minimizing the function of the sum of deviations of calculated values from experimental ones is applied. Thus, the reaction rate constants were chosen for the developed model.

The catalytic cracking process is specific and depends on several technological factors such as temperature, pressure, type of catalyst and reactor, and contact time. This article presents a review of foreign industrial zeolite-containing catalysts RDM SWM, and Russian microspherical catalyst “Oktifayn”, granular cracking catalysts “adamant”. On the basis of experimental and production data it is possible to conduct mathematical modeling of catalytic cracking process, and to select constants of rates of chemical transformations for each of types of catalysts.

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