A. V. Kravtsov

Thermodynamic stability of coke-generating compounds formed on the surface of platinum dehydrogenation catalysts in their oxidation with water

Results of thermodynamic analysis and mathematical simulation of the deactivation of a platinum dehydrogenation catalyst by coke-generating compounds are presented. An approach to increasing the catalyst on-stream time has been proposed, suggesting implementation of a procedure for calculating the optimal flow rate of water fed to the reactor to maintain the conditions of thermodynamic equilibrium of the coke formation reaction and oxidation of intermediate condensation products with water.

Developing a Method for Increasing the Service Life of a Higher Paraffin Dehydrogenation Catalyst, Based on the Nonstationary Kinetic Model of a Reactor

The service life of an industrial catalyst can be prolonged by improving the technological conditions of its operation. This allows us to maximally eliminate the catalyst deactivation factors. A specific feature of the catalytic dehydrogenation of hydrocarbons is its nonstationarity produced by the deactivation of catalysts. The results of modeling the industrial catalytic process of C9-C14 paraffin dehydrogenation—the key stage in the production of linear alkylbenzenes—is discussed in this paper. We consider (1) thermodynamic analysis of reactions by means of quantum chemistry, (2) estimation of the kinetic model’s parameters by solving the inverse kinetic problem, (3) selection of an equation that describes the coke deactivation of a catalyst, and (4) development of a method for increasing the service life of a dehydrogenation catalyst using a nonstationary model based on the quantitative consideration of the water added to a reactor within a temperature range of 470–490°C. The higher alkane dehydrogenation flowsheet proposed on the basis of these models allows us to predict the operation of a reactor in different water supply regimes. It is shown that the service life of a catalyst grows by 20–30% on the average, if water is fed by increasing portions.

Development of an intelligent system for controlling paraffin dehydrogenation catalyst operation in production of linear alkyl benzenes

In this article, we present the main results on the modeling of the industrial process of catalytic C9–C14n-paraffin dehydrogenation, which is one of the technological stages in the production of linear alkyl benzenes used for the synthesis of synthetic detergents. The application of the developed mathematical model for evaluating the influence of the raw material composition on the target product yield is considered. The calculation results on the optimal technological modes for different dehydrogenation Pt catalysts and also on the prediction their lifetime are given.

Kinetic model of the catalytic reforming of gasolines in moving-bed reactors

A mathematical model of the catalytic reforming of gasolines in a reactor with continuous catalyst regeneration is proposed. The model takes into account the motion of the catalyst, changes in its activity along the bed height, and the dependence of its activity on the circulation ratio. The kinetic parameters of the Pt-Sn catalyst are determined under operational conditions by solving the inverse kinetic problem. The composition of the reformate component as calculated by the model coincides with the experimental data within the accuracy of chromatographic analysis. The proposed model is invariant to the composition of raw materials and can be used for predictive calculations.

Computer Program for Optimizing Compounding of High-Octane Gasoline

A procedure for calculating octane numbers of commercial gasolines with due regard for the intensity of interaction between molecules of blend components, and the mechanism of interaction of interaction of anti-knock additives with hydrocarbons is elaborated. Based on the models developed, a computer program is created for optimization of the process producing high-octane gasoline. The program allows quick and precise determination of the optimum ratio of components, which ensures production of commercial gasolines that meet all the requirements of regulatory documents.

Mathematical model for the process of benzene alkylation by higher olefines

In this work, we considered the results on the modeling of the industrial catalytic alkylation process, one of the terminal stages in the production of linear alkyl benzene sulfonates (LAS) used as the basis for the synthesis of synthetic detergents. Taking into account the experimental data obtained under regular operational conditions of alkylation unit at the Linear Alkyl Benzene and Linear Alkyl Benzene Sulfonates (LAB-LAS) Plant of OOO Kirishinefteorgsintez (OOO KINEF), we developed a scheme of chemical reactions for the purpose of creating the kinetic model for the alkylation process. The kinetic parameters of this model were identified by solving the inverse kinetic problem under the lack of necessary experimental data, so we had to reduce the number of estimated kinetic parameters with the use of thermodynamic data. The software model of this process permitted us to calculate quite precisely the material and heat balances of the reactor and also to study the influence of changes in different technological parameters on the effectiveness of the process.

Monitoring of the commercial operation of reforming catalysts using a computer simulation system

A methodology of constructing nonstationary kinetic models of multicomponent catalytic processes of hydrocarbon conversion on platinum-containing catalysts was developed. Their kinetic and technological parameters in industrial catalytic reforming were estimated. The simulation system in gasoline production allows for the testing and choosing of an optimum catalyst depending on the composition of the processed hydrocarbon raw materials. The developed testing technique is based on the processing of the results of the commercial operation of platinum-containing reforming catalysts using the computer simulation system. It allows the estimation of kinetic parameters, the prediction of selectivity, and raw cycle duration after catalyst regeneration under conditions of commercial operation, taking into account the reactivity of hydrocarbons.

Optimizing the catalyst circulation ratio in a reformer with a moving bed via a combination of real and computational experiments

During the operation of continuous catalyst regeneration reformers, the problem of optimizing the catalyst circulation ratio in the reactor-regenerator system arises. This problem is solved by a combination of real and computational experiments to investigate the regularities of coking on a catalyst’s surface. Based on TGA results for industrial Pt-Sn/γ-Al2O3 catalyst, it is concluded that amorphous coke is formed on the catalyst’s surface during reforming, its quantity at the reactor block outlet being 4–6%, depending on the feed composition and technological parameters of the process. The specific surface of samples is 152 m2/g for the fresh catalyst, 140 m2/g after regeneration, and 118 m2/g at the reactor outlet, which correlates with the quantity of coke on the surface of samples. Mathematical analysis of the coking processes in a reformer with a moving bed show that the catalyst circulation ratio must be maintained in the range of 0.008–0.010 m3/m3 to increase the operating efficiency of an industrial unit. Maintaining optimal conditions enables us to control the coking process, keeping coke concentration as low as possible and the catalyst specific surface as high as possible.

Raising the efficiency of linear alkylbenzenes production Using the computer modeling system

Computer modeling system is developed for the production of linear alkylbenzenes — the raw stock for biodegradable synthetic detergents. The system allows raising the efficiency of plant operation by choosing the most appropriate catalyst, computing optimal water supply into the reactor calculating recycling and heat outfit schemes for the installation.

Mathematical modeling of methyl tert-butyl ether reactive distillation synthesis

This paper is devoted to forming the mathematical model of methyl tert-butyl ether (MTBE) production by means of reactive distillation. The model based on physicochemical principles of the process and can be used for further designing, researching and stability analysis.