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Relevance. Caused by the need to increase production of light olefins. The use of advanced process control systems and Real–Time Optimization makes it possible to increase the efficiency of steam cracking plants, but requires a high-speed mathematical model of the process. Aim. To select a method for numerical solution of systems of ordinary differential equations, which provides the highest speed when calculating the reaction coil of a steam cracking furnace. Reducing the time spent on calculating each scenario will allow the proposed model to be used for real-time process optimization tasks. Object. Mathematical model of ethane steam cracking, numerical methods for ordinary differential equations systems solution. Methods. System analysis, mathematical modeling. To solve the ordinary differential equations systems, various explicit numerical methods were used, differing in approach to integration step determination. Results. The authors have developed and tested a steady-state model of ethane steam cracking. The developed model was used to compare the calculation time required for solving ordinary differential equations systems using different numerical methods. It was demonstrated, that the use of an adaptive integration step reduces calculation time by more than 20 times (from more than 11 hours to 34 minutes) while maintaining the accuracy of calculations. This is due to different reaction rates through the length of the reaction coil – in areas of high temperatures and high concentrations of reagents, a reduction in the integration step is required to obtain the desired accuracy. And in low reaction rates areas an increase in the step and reduction in the total calculated iterations are acceptable.

The relevance of this study is caused by the need for import substitution of software in the field of design, modeling and optimization of the gas and oil processing. Almost all software for modeling used at oil and gas entities are the developments of the USA, Canada, Great Britain and other countries. In the current conditions of sanctions risks on using imported software for modeling technological processes, the development and rapid adaptation of engineering mathematical models of all basic oil refining processes are an extremely urgent task. These models will further become the basis of Russian import-substituting software products. Over the course of 30 years, the National Research Tomsk Polytechnic University has been researching the processes of the motor fuels production. On the basis of these studies the reliable mathematical models have been developed for technologies such as catalytic reforming of gasoline, isomerization of the hydrocarbons pentane-hexane fraction, catalytic cracking of vacuum distillate and mixed petroleum feedstock, hydroprocessing of petroleum fractions, compounding of high-octane gasolines, and others. Distinctive features of the developed mathematical models are related to following: firstly, they are built on the basis of real industrial data on the operation units at various refineries and, secondly, they take into account the main fundamental physical and chemical laws of reaction mechanisms, the catalyst deactivation as well as the macrokinetic factors of motor fuel production processes. The solution of multicriteria problem of optimizing the technology of preparation of motor fuels (gasoline and diesel fuels) is possible using the method of mathematical modeling on a physical and chemical basis. This approach takes into account the thermodynamics and kinetics of hydrocarbon conversions on the catalyst surface, as well as the non-stationarity of the processes due to coking, aging and poisoning by harmful impurities of the catalyst, changes in the chemical composition of the feedstock. The aim of this study is to develop the technical solutions aimed at improving the efficiency of multi-stage gasoline production using the engineering models of oil refining processes. The method of research is based on using the mathematical modelling method for multi-stage processes of petroleum feedstock refining. The group and individual composition of various petroleum fractions determined by chromatographic methods, were used as an initial data. Results. The effect of the component composition of the processed feedstock of catalytic reforming on the qualitative and quantitative properties of the components of commercial gasoline was estimated and predicted. The use of the catalytic cracking model showed that when processing the feedstock with a lower content of aromatic hydrocarbons and resins the coke content on the catalyst is lower by 0,15 % wt. This leads to increasing the catalyst activity and the desired product yields by 6,7 % and 4,9 wt. % in comparison with the feedstock with higher content of resins and aromatics.The maximum gasoline yield for two types of the feedstocks (55,4 and 56,5 % wt.) which is achieved at 536,0 and 534,0 °C was determined according to their hydrocarbon compositions. The predictive calculations with an assessment of how the composition of the catalytic cracking gasoline influences the formulation and commercial quality of the commercial gasoline using the lighter catalytic cracking feedstock, were performed. The possibility of increasing the amount of the catalytic cracking gasoline into the commercial gasoline formula is shown. The cost of motor fuel production in this case is reduced from 0,1 to 1,0 %.

The relevance of the research is caused by the need of alkenes production increase as well as deepening understanding of the coke formation. The direction of petrochemical complex development and increase of pyrolysis efficiency is resources-saving, minimizing the volume of operations cost and the probability of occurrence of accidents. The main aim of the research is to develop a mathematical model for gasoline fraction pyrolysis, which will consider coke formation and its effect on the kinetic, hydrodynamic and thermodynamic components of the process. Object of the research is gasoline fraction pyrolysis process; dynamic of hydrocarbon stream composition during the process and coke formation side process. Methods. The methodological basis of the research is the system analysis and the method of mathematical modeling. In addition, quantum-chemical methods are used to calculate the thermodynamic and kinetic parameters of target and side chemical reactions occurring during the processing of hydrocarbon raw materials, and electron-structural methods based on the density functional theory; methods of computational fluid dynamics for the study of flow regimes and the deposition of coke particles on the walls of the coil; developed experimental methods for determining the optimal consumption of hydrocarbon raw materials and steam, predicting the duration of the inter-regeneration cycle of the pyrolysis furnace. Results. A non-stationary model of gasoline fraction pyrolysis was created to describe the coking side process along the length of the pyrolysis tube and over time. With the model, the rate of coke layer formation was calculated considering the technological parameters and the composition of feedstock. The calculated rate is 3,12∙10–7 mm per second. The results also made it possible to obtain the thickness distribution of the coke layer in the radiant coil, which indicates the acceleration of side processes towards the end of the process. This is due to formation of a significant amount of unsaturated compounds. It was found that changing the main parameters has two opposite effects. Thus, with an increase in temperature and pressure, both the yields of target products and the growth rate of the coke layer increased. An increase in the consumption of raw materials leads to a decrease in both of these parameters.

The relevance. Lack of experimental data that allow developing a scientifically based method for calculating and designing film-type reactors, which are also used to produce alkylbenzenesulfonic acids. These acids, in their turn, are currently the main components of synthetic detergents. The issue of increasing reactor equipment efficiency can be most effectively solved using mathematical models built on a physical and chemical basis. The aim. Development of a mathematical model of alkylbenzenes sulfonation, taking into account a substance mass transfer from a gas phase to a liquid phase. Software implementation of the developed model, as well as the use of the developed mathematical model for studying the influence of the process parameters on its efficiency. Object. Alkylbenzenes sulfonation with sulfuric anhydride in a multitube film reactor. Methods. Mathematical modeling is used to perform all computational operations, a modern high-level general-purpose programming language with automatic memory management is used. The quantum-chemical methods for determining thermodynamic parameters of chemical reactions were used. Results. The paper considers the principles of constructing a mathematical model of sulfonation. The authors have developed the calculation program in the Python programming language and assessed the accuracy of description of a real process and the influence of the system technological parameters on a product yield and quality, taking into account a substance interfacial transfer. The system of practical recommendations for improving the alkylbenzenes sulfonation resource efficiency was developed. The mathematical model adequately describes the process. The calculated data are compared with the real data from the operating unit for alkylbenzenes sulfonation with sulfuric anhydride.