OIL AND GAS CHEMISTRY

The paper presents the results of studying the coke formation process depending on the composition of model mixtures. Thermal cracking of SARA fractions of heavy, highly resinous, asphaltene-rich crude oil from the Zyuzeevskoye field (Republic of Tatarstan), as well as cracking of model mixtures of oils + resins and oils + asphaltenes, were studied. Material balances of the cracking processes and coke yields at a temperature of 450 °C for 120 minutes were determined, and the structural characteristics of new and transformed resins and asphaltenes formed during cracking were studied. It was shown that during cracking of individual components, the yield of insoluble coke-like products (coke) increases in the following order: saturated hydrocarbons → aromatic hydrocarbons → oils → resins → asphaltenes. During cracking of model mixtures, the coke yield increases in the following order: mixture of oils + resins → mixture of oils + asphaltenes. It has been established that changing the dispersion medium composition during cracking of model oil + resin and oil + asphaltene mixtures affects the direction of thermal transformations, leading to a slower rate of condensation reactions and, consequently, a decrease in the intensity of coke formation. Varying the dispersion medium composition under certain conditions can be used to reduce coke yield, which is important in heavy hydrocarbon feedstock processing. The presence of virgin and converted resins and asphaltenes in the cracking products of model mixtures, characterized by a high degree of aromaticity and a low content of alkyl substituents, serves as a reserve for their participation in polycondensation reactions leading to coke formation. It has been shown that resins not only act as coke-generating components but also serve as a potential source of light petroleum products in heavy hydrocarbon feedstock upgrading processes.

Lignin is a water-insoluble, three-dimensional cross-linked polymer, which is the aromatic part of wood raw material, connected to the carbohydrate part (cellulose) by ether bonds. The sulfonation of lignin with the aim of converting it into a soluble state is carried out by sulfur-containing agents, as a result of which a sulfonate group (-SO₃H) is built into its monomeric phenylpropane unit. The resulting byproduct is called technical liquid lignosulfonate (LST). The possibility of determining the content of SO₃H-groups in LST by different methods of delignification and the comparative characteristics between them have been studied in the work. In practical terms, this makes it possible to evaluate their reactivity and predict the production of a number of products and reagent systems based on them.As a result, the quantitative content of SO₃H-groups has been determined, which for neutral sulfite and sulfite LST amounted to 3.10% and 4.89% per macromolecule.

This paper presents the results of a study of the physicochemical properties of catalytic systems based on molybdenum carbide and ZSM-5 zeolite. The resulting systems are planned for use in the hydrodimerization process of diesel fuel. The study of the physicochemical properties will provide the necessary information for further optimization of the synthesis conditions for the catalytic systems. Based on the specific surface area data, changes in the main textural characteristics of the Mo_xC_y/ZSM-5 system were identified compared to the initial pure zeolite. Furthermore, the results confirm the successful application of the hydrogenating-dehydrogenating component to the surface of the zeolite component using incipient wetness impregnation. IR spectroscopy results reveal, in addition to the absorption bands characteristic of ZSM-5 zeolite, the presence of absorption bands of functional groups responsible for vibrations of the Mo-C bond. The phase composition of the resulting system was also determined using the X-ray diffraction data. It was established that the active metal particles are highly dispersed, and no undesirable low-activity phases were detected in the resulting system.

In this study, modified sorbents based on natural clays were prepared and characterized. Spectroscopy (SEM, FTIR, X-ray diffraction, and X-ray phase analysis) was used to investigate the structure and physicochemical properties of modified environmentally friendly sorbents based on alginates, bentonite, and nanoparticles. FITR spectroscopy was used to identify coordination centers that can participate in chelation. A method for determining the sorption value and conducting a kinetic analysis of the modified sorbent was studied. It was established that the naturally modified composites are quite effective sorbents for removing phosphates from aqueous solutions and can be used to treat industrial wastewater with high acidity. The study demonstrated that the proposed adsorbent has the potential to remove phosphates from contaminated water and improves existing municipal wastewater treatment technologies by reducing the concentration of phosphorus-containing contaminants.

The article outlines the relevance and necessity of improving diesel fuel. It has been shown that it is possible to effectively reduce harmful emissions from its combustion using additives of a certain chemical composition. It is proposed to use oxygenates (oxygen-containing compounds) of various classes (alcohols, esters, ketones) as additives. The effect of isopropanol, ethylcarbitol, and dimethylcarbonate as additives on the properties of diesel fractions has been studied. For analysis, narrow straight-run diesel fractions produced by JSC TAIF-NK of the following fractional composition were taken: 180-240, 240-290 and 290-350°С, used for the production of commercial diesel fuel of various grades. The most suitable additive to straight-run diesel fractions, dimethyl carbonate, has been determined, which effectively reduces the amount of actual resins in diesel fractions and improves their low-temperature properties.

The article discusses research conducted in the 1970s and 1990son the formation of the octane characteristics of alkylbenzines and the effect of the mixing intensity and the parameters of the alkylation process on the octane number of alkylate. The importance of scientific research and the introduction of new technologies to improve the efficiency of alkylbenzine production is emphasized, which, in turn, shows the contribution of GrozNII to the development of the domestic petrochemical industry.