Elena Ivashkina

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 approach to modelling and optimization of non-stationary catalytic processes in oil refining and petrochemistry

Abstract An approach to modelling of non-stationary catalytic processes of oil refining and petrochemistry is proposed. The computer modelling systems under development take into account the physical and chemical reaction laws, raw materials composition, and catalyst nature. This allows using the software for the optimization of process conditions and equipment design. The models created can be applied for solving complex problems of chemical reactors design; calculation of different variants of industrial plants reconstruction; refining and petrochemicals catalysts selection and testing; catalyst service life prolongation; determination of optimum water supply into the alkanes dehydrogenation reactor; optimization of products separation in the benzene alkylation process.

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.

Effect of thermodynamic stability of higher aromatic hydrocarbons on the activity of the HF catalyst for benzene alkylation with C9-C14 olefins

Results of thermodynamic analysis of reactions occurring during the alkylation of benzene with C9-C14 olefins, including the reversible reactions of formation of high-molecular-mass aromatic hydrocarbons, are presented. The thermodynamic relationships revealed have formed the basis for deriving a mathematical model of the alkylation process with allowance for alteration in the activity of the HF catalyst. It has been shown that the buildup of higher aromatic hydrocarbons in the alkylation reactor has a detrimental effect on the properties of HF. Operating modes and controlling parameters of the main stages of the production f linear alkylbenzenes to ensure the maximal efficiency of the process and maintain the activity of the HF catalyst at the optimal level have been determined.

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.

Determination of the Optimal Operation Mode of the Platinum Dehydrogenation Catalysts

The main results of thermodynamic analysis and mathematical simulation of the deactivation of a platinum dehydrogenation catalyst by coke-generating compounds are presented. Developed model allows 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. A comparative evaluation of different raw cycles of platinum-dehydrogenation catalysts is presented and shown to cause reduced production of the desired product was the change the composition of the feedstock.

Raising the efficiency of higher alkanes dehydrogenation process

Recent development of the consumer market is actively stimulating the advances in industry, including petrochemicals. Particularly, active development of the production of synthetic detergents and linear alkylbenzenes (LAB), demand growth of 6% per year. High demand for LAB (which is the raw material for different detergents) is caused primarily by the fact that the synthetic detergents made from these substances are characterized by the balance between the products environmental quality, washing power and the price. The biodegradability of detergent is directly connected to the composition of its surface-active part. This is why there is great need to increase the productivity of existing industrial plants for LAB, as well as to increase the depth of crude oil refining with reduced losses of heat and power at each stage of production. In this case improving the technological process is closely related to the quality of the equipment and the efficiency of the catalyst used. In the course of work the formalized reaction network of process was built, and the kinetic and mathematical models were developed. Kinetic and mathematical models were designed to implement in the computer modeling system, based on the formalized reaction network of process. A possible method of Pt-catalyst recovery has been offered for higher alkanes dehydrogenation process.

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.

Comparative analysis of catalyst operation in the process of higher paraffins dehydrogenation at different technological modes using mathematical model

Abstract This paper presents the results of comparative analysis of three run cycles of platinum catalyst for higher paraffins C9–C14 dehydrogenation process, performed using mathematical model. The results of model calculations were compared with the experimental data obtained at the industrial unit. It was established that deactivation of the platinum dehydrogenation catalyst is influenced by the technological modes of its operation, such as temperature, pressure, hydrogen/feedstock molar ratio and water supply. In the process of higher paraffins dehydrogenation, the phenomenon of platinum catalyst self-regeneration is observed. This occurs due to the action of feedstock components, in particular water and hydrogen involved in oxidation and hydrogenation of intermediate condensation products (coke structures). Model calculations showed that with a decrease in the hydrogen/feedstock molar ratio and simultaneous increase in water supply, depending on the temperature and composition of feedstock, it is possible to slow down deactivation process and increase the catalyst service life. This fact was experimentally confirmed at industrial unit.