The paper describes the physicochemical characterization and catalytic testing of MFI zeolites with different SiO2/Al2O3 ratios synthesized by steam-assisted crystallization (SAC) and modified with phosphorus (4 wt

The authors study the effect of the type of zeolite (SAPO-11, ZSM-22, ZSM-23, and ZSM-12) in a support (ratio zeolite : Al2О3 = 30 : 70) on the physicochemical properties of Pt/Al2O3-zeolite catalysts and the composition of products from the hydrodeoxygenation of sunflower oil on them. The possibility of the complete hydrodeoxygenation of sunflower oil at temperatures of 320–350°C, a pressure of 4 MPa, and a weight hourly space velocity (WHSV) of 1 h−1 is shown with 75–82

Results of studying ethanol conversion to aromatic hydrocarbons (benzene, toluene, xylenes) that are currently available in the scientific literature are discussed and systematized. The features of ethanol conversion in the presence of zeolite catalysts and the mechanism of each individual stage of ethanol conversion to aromatic hydrocarbons are discussed. The effect of the zeolite catalyst composition, the feedstock composition, and ethanol conversion process conditions is demonstrated. The effect of the modifier of a zeolite catalyst on the aromatic hydrocarbon selectivity is shown. This review can be of interest and of use to researchers of zeolite catalyst systems and alcohol conversion processes.

The effect exerted by the content of ZSM-22 zeolite (15–70 wt.%) in the support on physicochemical properties of Pt/ZSM-22-Al2O3 catalysts was investigated. The study revealed the dependence of the yield and composition of the hydrodeoxygenation products of sunflower oil obtained over these catalysts on temperature (310–340 °С), pressure (3–5 MPa) and mass flow rate (0.8–3 h–1). The possibility of complete hydrodeoxygenation of sunflower oil to obtain hydrocarbons C5+ containing up to 72 % of isoparaffins with the yield of 75–79 wt.% was demonstrated.

This paper proposes a novel approach to the extraction of cluster structures from a ZSM-5 zeolite lattice. The approach involves transforming the zeolite crystalline structure into a directed molecular graph followed by identifying cycles from which cluster structures are generated. One advantage of this approach is the complete similarity of the resultant cluster structures at equal input data, making the DBSCAN clustering method applicable to the identification of unique structures. Furthermore, this approach is effective in identifying the active and extended regions within a multilevel ONIOM model for subsequent quantum-chemical calculations. Finally, the proposed approach makes it possible to automate the extraction of cluster structures from ZSM-5 crystals and to select the most important structures for further analysis. To validate its efficiency, the novel approach was applied to identify the most probable location of Zn2+ cation-exchange sites in ZSM-5.

The physicochemical properties of ZSM-5 zeolite samples modified with alkali metal cations (e.g., Li+, Na+, K+, and Cs+) were characterized. It was demonstrated that increasing the metal load led to a decrease in the textural properties of the zeolite such as specific surface area, total pore volume, and micropore volume; furthermore, it reduced the total concentration of acid sites by 23–25

The review summarizes and critically analyzes the results of exploratory and basic studies carried out mainly in the last 10 years concerning the mechanism and role of hydrogen transfer reactions in hydrocarbon conversion processes. A discussion addresses the established views on the regularities of these reactions (mainly involving hydrogen–hydrogen, carbon–carbon and carbon–hydrogen bonds) in various systems containing cations of d-, p - and s-elements. The features of intermolecular hydrogen transfer reactions involved in the zeolite-catalyzed cracking of hydrocarbons are considered. Data on the development of compositions and investigation of properties of modern zeolite-based catalysts for hydrocarbon cracking are discussed. The attention is focused on the role of intermolecular hydrogen transfer in this process, especially in the transformations of heteroatomic compounds. Regarding zeolite compositions, the main attention is paid to the influence of the acid site distribution on the zeolite surface on the hydrogen transfer reactions and the role of extra-framework aluminium species and added modifier cations in these processes. The results of studies of hydrogen transfer by model calculations and by drawing analogies are presented. It is demonstrated that intermolecular hydrogen transfer reactions must be taken into account while addressing problems of improving the cracking catalysts and creating catalytic compositions for joint processing of sulfur, nitrogen and oxygen compounds together with hydrocarbons in the catalytic cracking. The bibliography includes 249 references.

The paper describes the physicochemical characterization and catalytic testing of MFI zeolites with crystal sizes ranging from 0.15 to 6 μm supplied by different manufacturers. The physicochemical properties were examined by atomic absorption spectrometry, X-ray fluorescence analysis, scanning electron microscopy, low-temperature nitrogen adsorption, and ammonia temperature-programmed desorption. The MFI zeolites were then added to a cracking catalyst and subjected to catalytic testing in the conversion of cyclohexane and hydrotreated vacuum gas oil (HTVGO). It was found that the conversion of the model cyclohexane feedstock was significantly enhanced when the crystal size of the MFI zeolite added to the cracking catalyst was reduced from the micro- to submicro-scale; on the other hand, an equal downsizing had almost no effect on the conversion of the real HTVGO feed. However, the use of submicrosized MFI crystals in HTVGO cracking decreased the contribution of hydrogen transfer reactions, thus reducing coke deposits.

The present report is devoted to refining of thermolysis oil (TO), which was obtained from the mixture of different plastics and contained 2.24% of chlorine. The process of refining of thermolysis oil includes combi-nation of hydrotreating of TO (80%) and SR VGO (20%) mixture with NiMo supported catalysts. The following process includes FCC treatment of the obtained hydrotreating products. All used conditions were typical for industrial FCC process of SR VGO with its preliminary hydrotreating. The influence of hydrotreating catalyst type and hydrotreating temperature on the composition and properties of hydrotreating products was studied. Moreover, the effect of these parameters on the composition and yields of FCC products was established. The main reasons of hydrotreating catalysts deactivation during refining of Cl containing thermolysis oil were investigated by XPS, HAADF, HCNS-analysis. It was revealed that the best hydrotreating temperature was 360 degrees C, while the best used catalyst was NiMoP/Al2O3.

The effect of the zeolite type (SAPO-11, ZSM-22, ZSM-23 and ZSM-12) in the support (the zeolite to Al2О3 ratio of 30 : 70) on physicochemical properties of Pt/Al2О3-zeolite catalysts as well as on the yield and composition of the products of sunflower oil hydrodeoxygenation over these catalysts was studied. The possibility of complete hydrodeoxygenation of sunflower oil at temperatures 320–350 °C, pressure 4 MPa, and mass flow rate 1 h–1 with the yield of liquid products 75–82 % was demonstrated. The fraction of isoalkanes and the yield of products from direct hydrodeoxygenation increase with the concentration of Broensted acid sites in the catalyst in the following series: 1%Pt/Al2O3-ZSM-22 < < 1%Pt/Al2O3-ZSM-12 < 1%Pt/Al2O3-ZSM-23 < 1%Pt/Al2O3-SAPO-11.

The amorphous aluminosilicate – alumina systems were examined using various physicochemical methods, including the analysis of 27Al NMR spectra of solid samples, estimation of the catalyst acidity by temperature-programmed desorption of ammonia, investigation of the sample structure by X-ray diffraction analysis, and thermogravimetric analysis of the samples. A study on the catalytic properties of the samples upon cracking on the model feedstock n-dodecane in a mixture with 2-methylthiophene revealed that conversion of the feedstock increases in the series: 100 % Al2O3 (AH) > 70 % Al-Si + 30 % Al2O3 (AH) > 30 % Al-Si + 70 % Al2O3 (AH) > 100 % Al-Si (AH – aluminum hydroxide obtained by sulfate method; Al-Si – amorphous aluminosilicate). An increase in the calcination temperature of the samples from 500 to 700 °C decreases the conversion of the feedstock. The growing contribution of hydrogen transfer reactions leads to an increase in the formation selectivity of hydrogen sulfide and a decrease in the content of sulfur compounds in the liquid products.

The effect of an oxygen-containing compound on the cracking of an aromatic hydrocarbon is studied using the example of a model phenol–tetralin mixture. An analysis of the temperature dependences of the cracking rate constant of tetralin and tetralin in a mixture with phenol indicates that tetralin cracking is ihhibited during its co-conversion with an oxygen-containing compound due to the greater adsorption capacity of phenol on the catalyst’s surface. It is found that phenol in the model mixture changes the composition of liquid products, especially at low cracking temperatures. The effect of water on the conversion of a phenol-tetralin mixture is studied. It is established that water in the model feedstock reduces the inhibition of the cracking reaction of an aromatic hydrocarbon by an oxygen-containing compound. Based on the results of catalytic reactions, it is determined that when water is added, the level of the overall conversion of the mixture and the conversion of tetralin increase regardless of temperature. No appreciable qualitative differences between the distributions of cracking products in model mixtures with and without water have been revealed.

A phenol–tetralin model mixture was used to investigate the effect of the oxygen-containing compound on the cracking of aromatic hydrocarbon. The analysis of temperature dependences of the cracking rate constant for tetralin and tetralin in a mixture with phenol indicates that the cracking of tetralin is hindered in the case of its simultaneous conversion with the oxygen-containing compound due to higher adsorptivity of phenol on the catalyst surface. It was found that the presence of phenol in the model mixture changes the composition of liquid products, especially at a low cracking temperature. In addition, the effect of water on conversion of the phenol–tetralin mixture was studied. The presence of water in the model feedstock was shown to decrease the hindering of the aromatic hydrocarbon cracking by the oxygencontaining compound. The results of catalytic transformations revealed that the addition of water increased total conversion of the mixture and conversion of tetralin irrespective of temperature. Essential qualitative differences in the distribution of cracking products of the model mixtures containing or not containing water were not found.

The influence of the composition of a zeolite-containing catalyst on the target product distribution in joint cracking of vacuum gasoil with vegetable oils was studied. Introduction of ZSM-5 zeolite into the catalyst formulation favors the formation of light olefins С 2 –С 4 : the yield of propylene and butylenes increases. Analysis of the distribution of target cracking products depending on the kind of vegetable oil shows that the maximal yield of С 2 –С 4 olefins is reached when using oils with increased content of saturated fatty acids, especially at high content of ZSM-5 zeolite in the catalyst active component. To ensure the primary cracking of the mixed feedstock, the cracking catalyst matrix should have developed surface and high acid properties.

The influence of the zinc incorporation method (ion exchange, impregnation) and its content (from 0.25 to 0.75 wt %) in ZSM-5 zeolite on the physicochemical characteristics of the zeolite (textural parameters, concentration of acid sites) and on the catalytic activity of cracking catalysts with the additives containing the modified zeolites in transformations of hydrotreated vacuum gasoil was studied. The zinc introduction by impregnation leads to a slight decrease in the zeolite specific surface area and micropore volume from 420 to 380 m2/g and from 0.131 to 0.117 cm3/g, respectively, and the total concentration of acid sites at the maximal zinc content increases by 17% compared to unmodified ZSM-5. Modification of the zeolite samples with zinc by ion exchange does not alter the main pore structure parameters compared to the initial zeolite, whereas the acid site concentration reaches the highest values (up to 2025 μmol/g). With an increase in the zinc content of ZSM-5 zeolite, with both modification methods (ion exchange, impregnation), the yield of the gasoline fraction and aromatic hydrocarbons in liquid products of cracking of hydrotreated vacuum gasoil increases.

The effect of adding clay with different contents of iron oxides to a catalytic cracking system on the distribution of feedstock sulfur in synthesized products and the amount of sulfur oxides formed during the regeneration of coked catalyst after the cracking of a model sulfur-containing feedstock with a sulfur content of 10 000 ppm, derived from 2-methylthiophene or benzothiophene has been studied. The fraction of the feedstock sulfur converted into liquid products and coke can be seen to grow when a sulfur-containing component with a higher molecular weight is used. Raising the content of iron oxide in the catalyst from 0.61 to 1.53 wt % increases the yield of liquid products during the cracking of a model feedstock, reduces the conversion of a model hydrocarbon. The yield of coke on the catalyst grows from 3.8 to 5.2 wt %, and the fraction of feedstock sulfur converted into SO 2 quadruples.

This paper describes the investigation of the individual effects of theintroduced quantities of rare-earth elements (REE) and ofSiO2/Al2O3ratio on the physicochemical characteristics (textural properties and acidity)of Y zeolite, as well as on the catalytic activity of petrochemical crackingcatalysts based on the zeolites prepared, during the conversion of hydrotreatedvacuum gas oil (HTVGO). The amounts of REE oxides and the zeoliteSiO2/Al2O3ratio were quantified independently. An increase in REE oxide content in zeolitereduces its acidity. With an increase inSiO2/Al2O3ratio at constant REE oxide content, the concentration of acid sites decreases,while the specific surface area and pore volume change only insignificantly. Agrowth in the REE2O3 content leadsto a decline in the olefin yield from HTVGO cracking. Catalytic tests of theprepared catalysts demonstrated that an increase inSiO2/Al2O3ratio enhances the C2–C4 olefinyield from HTVGO cracking as a result of the smaller contribution of hydrogentransfer reactions.

The present work studies the influence of nitrogen compounds in hydrotreated fluid catalytic cracking (FCC) feedstock on the material balance of FCC process focused on petrochemistry. Vacuum gas oil was hydrotreated at the temperatures of 340-370 degrees C in typical FCC pretreatment conditions. The obtained hydrotreated products contained 370-750 ppm of nitrogen and 150-820 ppm of sulfur. Hydrotreated feedstock was exposed to the FCC process over a zeolite catalyst at the laboratory unit with a fixed bed catalyst at 527 degrees C and catalyst/oil ratio - 2-6. The FCC feedstock before and after hydrotreatment and FCC products were characterized by different methods to study the effect of nitrogen compounds on the FCC process.