INTEGRATION OF THERMO-, HYDRODYNAMIC, AND KINETIC FACTORS IN THE MATHEMATICAL MODELING OF THE CATALYTIC REFORMING PROCESS



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The study is devoted to the integration of various factors affecting technological processes in the oil refining industry. The aim of our research is to combine thermodynamic, kinetic and hydrodynamic aspects into a single model, as well as its validation based on experimental data and real-world operating conditions to ensure the accuracy and reliability of model predictions. The main research methods include statistical data analysis, process modeling and experimental studies at various stages of the technological cycle. As a result of the work, the key parameters that have the greatest impact on the quality of the final product and production efficiency were identified. In addition, recommendations for optimizing production processes based on the data obtained are proposed. The main conclusions of the study are that the integration of various factors can significantly improve production performance and reduce the cost of processing raw materials. The study highlights the importance of an integrated approach to the management of production processes in the oil refining industry, which can be useful for the further development of the industry.  The developed model can be used for training personnel in process simulation, featuring an intuitive interface that does not require deep programming knowledge, making it ideal for the initial training of specialists.

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Introduction. The production of petroleum products remains relevant in the world, despite the shift towards the use of alternative environmentally friendly energy sources. 
For the sustainable development of the country, it is necessary to take measures to optimize existing enterprises producing petroleum products (predictivity, energy conservation, resource efficiency, decarbonization, efficient operation and clean disposal options). 
There are three large oil refineries in Kazakhstan. According to the Annual Report - 2022 of JSC NC Kazmunaigas, Kazakhstan's refineries have the Nelson index [1]:
 
 Company No. Nelson Index
1 Atyrau Refinery 13.9
2 Pavlodar NHZ 10.5
3 Shymkent Refinery 8.2
 
Modern refineries in the USA and Europe have a Nelson index of over 15, while refineries with a Nelson index of at least 10 will be able to survive in market conditions [1]. 
The mathematical modeling method is ideal for further increasing the processing capacity and depth. The method effectively solves the problems of rational use of natural hydrocarbons, forecasting and planning the composition of products, optimizing existing oil refining plants, increasing resource efficiency, and energy saving. Also, using a mathematical model, it is possible to work out the technological modes of operation of new and existing equipment and adapt installations in conditions of changing the composition of raw materials.
The catalytic reforming process is one of the most important processes in oil refineries. Catalytic reforming of gasoline fractions is used to increase the octane number of gasoline by converting naphthenes and paraffins into aromatic hydrocarbons. This process also serves to produce raw materials for the petrochemical industry, benzene, toluene, xylene are key in the production of plastics, synthetic fibers, dyes and other chemical products.
In the field of oil refining, mathematical models for optimizing production processes have become widespread. Most of these methods are aimed at optimizing by a single criterion or parameter, known as the objective function. However, real-world tasks often require taking into account several criteria or parameters at the same time. For this purpose, artificial integral criteria are usually used, which include all relevant parameters in order to achieve the best solution.
When creating a mathematical model of catalytic reforming, it is critically important to take into account thermodynamic parameters (temperature, pressure, composition of initial reagents), kinetic parameters (reaction rate coefficients, reaction mechanisms and activation energy) and hydrodynamic parameters (flow velocity, velocity distribution and flow behavior). It is also necessary to take into account the catalyst parameters (type, composition and active surface of the catalyst), reactor parameters (type, size and shape) and heat transfer. All these factors affect the accuracy of the model and the effectiveness of predictions to optimize the process.
The aim of our research is to combine thermodynamic, kinetic and hydrodynamic aspects into a single model, as well as its validation based on experimental data and real-world operating conditions to ensure the accuracy and reliability of model predictions.
Materials and methods of research. The object of the study is the LK-6U catalytic reforming unit, with a capacity of 1000 thousand tons/year. The octane numbers of gasoline fractions subjected to catalytic reforming usually do not exceed 50-55 PPM. 
Catalytic reforming is a complex chemical process involving a variety of reactions that radically transform the hydrocarbon composition of gasoline fractions.
The basis of the process is the aromatization of gasoline, carried out by dehydrogenation of six-membered naphthenes and dehydrocyclization of paraffins:
dehydrogenation of six-membered naphthenes
 
dehydroisomerization of five-membered naphthenes
 
 
- dehydrocyclization of paraffins
 
" H- " C_6 H_14⟶(C_6 H_6)┬" benzene " +4H_2
- hydrocracking of paraffins
 
(C_8 H_18)┬" n-octane " +H_2⟶(C_5 H_12)┬" H-pentane " +(C_3 H_8)┬" propane " 
 
In addition, reactions of hydrodealkylation, conversion of six-membered naphthenes into paraffins, hydrogenolysis, etc. occur to varying degrees.
As a result of these reactions, the amount of aromatic hydrocarbons in the raw materials increases.
The reactions of dehydrogenation, dehydrocyclization, and dehydroisomerization are endothermic and proceed with a negative thermal effect. 
All these reactions can occur under the following operating parameters of the catalytic reforming unit:
a) the temperature in the reaction zone is 480-530 °C;
b) the pressure at the outlet of the third reactor is 20-30 kgf/cm2;
c) the volumetric feed rate of raw materials is 2-4 hours-1;
d) the multiplicity of circulation of VSG is 1200÷1500 nm3/m3;
e) the catalyst is polymetallic – RG-682 A1.6;
f) the service life of the catalyst is 7-10 years.
Raw materials – heavy gasoline fraction comes from the cube of the naphtha splitter section to receive the feed pumps of the reforming unit and is then fed to mix with hydrogen-containing gas. (Figure 1). 
 
 
R – Reactor; P– Furnace; S – Separator; T – Heat exchanger; F – Filter; CC – Circulating gas compressor; K – Stabilization column; E – Irrigation tank; XK – refrigerator condenser; X – Refrigerator; T – Heat exchanger; 
Figure 1 – Installation of catalytic reforming
 
2.1. Experimental research methods
At the first stage, the results of an experimental study were used. Data on the technological mode of the installation were taken from the factory (Table 1).  The data for calculations were obtained by chromatographic research method according to GOST R 52714-2018 "Automobile gasoline. Determination of individual and group hydrocarbon composition by capillary gas chromatography" [2]. An example of the chromatography under study is shown in Figure 2.  The mass concentration of each hydrocarbon component is calculated based on the normalized area and sensitivity coefficients [2, 3]. 
 
Figure 2 – Chromatogram of raw materials 
 
List of methods used [3-20]: 
1. GOST 31072-2002 "Oil and petroleum products Method for determining density, relative density and density in degrees by API hydrometer" for determining the density of raw materials of hydrotreated vacuum distillate and petroleum products of the catalytic cracking process.
2. ASTM D 1160-2010 "Determination of the fractional composition of heavy and residual petroleum products" for determining the fractional composition of the hydrotreated vacuum distillate of the catalytic cracking process.
3. GOST 32139-2013 "Oil and petroleum products. Determination of sulfur content by energy dispersive X-ray fluorescence spectrometry" to determine the mass fraction of sulfur in the hydrotreated vacuum distillate and the resulting petroleum products in the process of catalytic cracking.
4. GOST R 52714-2007 "Determination of individual and group hydrocarbon composition by capillary gas chromatography" for determining the hydrocarbon composition of gasoline in the catalytic cracking process using chromatograph CHROMATEK-KRISTALL 4000 version 2 with flame ionization detector, Chromatek Analyst software, capillary column DV-1, 100·0,25·0,55
. ST RK ASTM D 445-2011 "Method for determining the kinematic viscosity of transparent and opaque liquids (calculation of dynamic viscosity)".
6. GOST 1756-2000 (ISO 3007-99) "Petroleum products. Determination of saturated vapor pressure".
7. GOST R 50802-95 "OIL. Method for the determination of hydrogen sulfide, methyl and ethyl mercaptans".
8. GOST R 52247-2004 "Oil. Methods for the determination of organochlorine compounds".
9. GOST 11851-85 "Oil. The method of determining paraffin".
10. GOST 2477-2014 "Oil and petroleum products. A method for determining the water content."
11. GOST 21534-76 "Oil. Methods for determining the content of chloride salts".
12. GOST 6370-83 "Oil, petroleum products and additives. Method of determination of mechanical impurities". 
13. ASTM D6730-01(2011) "Content of individual components in fuels for internal Combustion engines".
14. ASTM D2427-06 "The content of light hydrocarbons in gasoline".
15. GOST R 51941-2002 "The content of aromatic hydrocarbons in gasoline".
16. ASTM D 4052 "Density".
17. ASTM D 86 "Fractional composition".
 
Table 1 – Technological parameters of the installation
Parameters Pressure, Atm Temperature Temperature difference
1 Reactor R-202 20 498,4 60
2 Reactor R-203 20 498,7 25
3 Reactor R-204 20 498,5 10
4 Volume of processed raw materials, t 637171
5 VSG consumption, m3/hour 194603
6 Humidity VSG, ppm 15.0
7 Sulfur in hydrogenate, ppm 0.10
8 Raw material consumption, m3/hour 130.0
 
2.2 Mathematical modeling of the catalytic reforming process
Mathematical modeling of chemical and technological processes includes a mathematical description through a series of complex computer calculations. This method allows you to quickly obtain detailed information about the operation of the designed installation and the patterns of the process under study, which opens up opportunities for further optimization. The main difficulties of this approach are related to the development of a mathematical model, the search for algorithms to solve it, and the creation of software for computer calculations.
At the first stage, it is necessary to determine the main chemical reactions occurring during the catalytic reforming process and their mechanisms, thermodynamic, kinetic and hydrodynamic parameters that take place in the reactor (enthalpy, entropy, Gibbs energy, the degree of transformation of the substance, the activity of the catalyst is also taken into account. 

 

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About the authors

Rizagul Dyussova

NPJS Company "Toraigyrov University"

Author for correspondence.
Email: rizagul.dyussova@gmail.com
ORCID iD: 0000-0003-3083-5255
Scopus Author ID: 57202057606

Candidate of Technical Sciences, Postdoctoral fellow of the Department of Mechanics and Oil and Gas Engineering

Kazakhstan, Pavlodar, Republic of Kazakhstan, Ak street.Chokina 139

Gaini Zhumagalievna Seitenova

ASSOCIATION OF PRODUCERS AND CONSUMERS OF PETROCHEMICAL PRODUCTS

Email: gainiseitenova@gmail.com
ORCID iD: 0000-0001-6202-3951
Scopus Author ID: 31067540200
ResearcherId: P-6620-2017

Candidate of Chemical Sciences, Head of the Project Office

Kazakhstan, Astana, Kunaeva 8, Business center "Emerald Quarter" , office 901

Ekaterina Andreyevna Zhamanova

Non-Commercial Joint-Stock Company "L.N.GUMILYOV EURASIAN NATIONAL UNIVERSITY",

Email: ekaterina.zakmanova1998@gmail.com
ORCID iD: 0000-0003-0545-5912
Scopus Author ID: 58368047200

Doctoral student of the Department of Chemistry

Kazakhstan, Astana, Satpayev str. 2

Yakobs Sergeevs

Non-Commercial Joint-Stock Company "TORAIGYROV UNIVERSITY"

Email: sergeevs_yakobs@mail.ru
ORCID iD: 0009-0009-2090-9143

Doctoral student of the Department of Mechanics and Oil and Gas Business

Kazakhstan

Moldir Barashkova

Non-commercial Joint Stock Company ATYRAU UNIVERSITY OF OIL AND GAS NAMED AFTER S. UTEBAYEV

Email: moldirborasheva1992@gmail.com
ORCID iD: 0009-0009-2842-0078
Kazakhstan, Atyrau, Republic of Kazakhstan, md. Privokzalny, 45A Baymukhanova str.

References

  1. About NC KazMunaiGas. Annual report for 2022 [Electronic resource]. URL: https://www.kmg.kz (date of reference: 07/27/2024).
  2. ST RK 1347-2005 Oil. General technical conditions [Electronic resource]. URL: https://online.zakon.kz/Document/?doc_id=30167328 (date of reference: 30.07.2024).
  3. GOST 31072-2002 Oil and petroleum products. The method of separation of power, state power and authority in the civil API by the hydrometer [Electronic resource]. URL: https://online.zakon.kz/Document/?doc_id=32308804 (date of application: 07/25/2024).
  4. Astm D 1160-2010 Determination of the fractional composition of heavy and residual petroleum products [Electronic resource]. URL: https://online.zakon.kz/Document/?doc_id=38992943 (date of reference: 07/25/2024).
  5. GOST 32139-2013 Oil and petroleum products. Determination of sulfur content by energy dispersive X-ray fluorescence spectrometry [Electronic resource]. URL: https://internet-law.ru/gosts/gost/72344 / (date of access: 07/25/2024).
  6. GOST R 52714-2007 Determination of individual and group hydrocarbon composition by capillary gas chromatography [Electronic resource]. URL: https://allgosts.ru/75/160/gost_r_52714-2007 (date of reference: 07/23/2024).
  7. ST RK ASTM D 445-2011 Method for determining the kinematic viscosity of transparent and opaque liquids (calculation of dynamic viscosity) [Electronic resource]. URL: https://online.zakon.kz/Document/?doc_id=31406764 (date of application: 07/23/2024).
  8. GOST 1756-2000 (ISO 3007-99) Petroleum products. Determination of saturated vapor pressure [Electronic resource]. URL: https://online.zakon.kz/Document/?doc_id=30007599 (date of application: 07/20/2024).
  9. GOST R 50802-95 Oil. Method for the determination of hydrogen sulfide, methyl and ethyl mercaptans [Electronic resource]. URL: https://online.zakon.kz/Document/?doc_id=30033909 (date of reference: 06/20/2024).
  10. GOST R 52247-2004 Oil. Methods for the determination of organochlorine compounds [Electronic resource]. URL: https://online.zakon.kz/Document/?doc_id=39385692 (date of application: 06/20/2024).
  11. GOST 11851-85 Oil. Method of paraffin determination [Electronic resource]. URL: https://online.zakon.kz/Document/?doc_id=30007754 (date of reference: 06/18/2024).
  12. GOST 2477-2014 Oil and petroleum products. Method for determining the water content [Electronic resource]. URL: https://online.zakon.kz/Document/?doc_id=33415695 (date of application: 07/18/2024).
  13. GOST 21534-76 Oil. Methods for determining the content of chloride salts [Electronic resource]. URL: https://online.zakon.kz/Document/?doc_id=30007909 (date of application: 07/18/2024).
  14. GOST 6370-83 Petroleum, petroleum products and additives. Method of determination of mechanical impurities [Electronic resource]. URL: https://online.zakon.kz/Document/?doc_id=30008237 (date of reference: 06/18/2024).
  15. ASTM D6730-01(2011) The content of identification data for internal control for drivers [Electronic resource]. URL: https://www.astm.org/standards/d6730 (date of reference: 08/18/2024).
  16. ASTM D2427-06 Content of light hydrocarbons in benzine [Electronic resource]. URL: https://www.astm.org/d2427-06r19.html (date of application: 06/20/2024).
  17. GOST R 51941-2002 Gasoline. Gas chromatographic method for the determination of aromatic hydrocarbons [Electronic resource]. URL: https://allgosts.ru/75/160/gost_r_51941-2002 (date of reference: 07/20/2024).
  18. ASTM D 4052 Density [Electronic resource]. URL: https://www.astm.org/standards/d4052 (date of reference: 07/27/2024).
  19. ASTM D 86 Missile System [Electronic resource]. URL: https://www.astm.org/standards/d86 (date of application: 07/27/2024).
  20. Seitenova G.Zh., Dyusova R.M., Burumbaeva G.R. Mathematical modeling of oil refining processes as a method of resource saving and energy efficiency // Scientific and technical journal "Oil and Gas". 2023. No. 1 (133). pp. 144-154.
  21. https://doi.org/10.37878/2708-0080/2023-1.13 Zainullin R.Z., Zagoruiko A.N., Koledina K.F., Gubaidullin I.M., Faskhutdinova R.I. Multicriteria optimization of a catalytic reforming reactor plant using a genetic algorithm // Catalysis in the oil refining industry. 2020. Volume 12. pp. 133-140. 10.1134/S2070050420020129.
  22. Smith J. M., Van Ness H. K., Abbott M. M., Swihart M. T. Introduction to thermodynamics of chemical engineering. 9th ed. – McGraw Hill Education, 2022.
  23. Ivanchina D., Chuzlov V.A., Ivanchin N.R., Borisov A., Seitenova G.Z., Dusova R.M. Frame production model of catalytic processing of petroleum raw materials for the representation of knowledge about the process // Oil and coal. 2021. Volume 63 (3).

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