A procedure for regenerating the hydroconversion catalyst precursor was studied. The procedure involves separation of the catalyst concentrate from the hydrogenizate vacuum residue by filtration, heat treatment of the concentrate to obtain the ash residue, and leaching of compounds of Mo and other metals from the ash residue with aqueous ammonia and nitric acid. As shown by X-ray diffraction analysis, the ash residue after the oxidation of the catalyst concentrate contains both individual molybdenum oxide (MoO3) and mixtures of double (NiMoO4, V2MoO8, NiV2O6, Na0.76V6O15) and triple (Fe4V2Mo3O20) oxides in the form of alloys. An efficient procedure is the pretreatment of the ash residue with 65

The catalytic activity of suspensions of cobalt-promoted molybdenum disulfide particles in hydroconversion of the petroleum vacuum residue was studied. Catalyst particle suspensions were prepared from inverse emulsions of aqueous solutions of the precursors (ammonium paramolybdate, cobalt nitrate or acetate) directly in the feed (in situ). Two procedures were used for preparing the promoted catalyst: consecutive or simultaneous addition of the precursors to the dispersion medium. The toluene-insoluble particles (TIPs) containing the spent catalyst had the size from 380 to 410 nm and contained the MoS2, МоО3, and Co9S8 crystalline phases. The cobalt-promoted dispersed catalyst exhibits the maximal activity in hydrodesulfurization and hydrogenation at the cobalt content of 33 at.

DFT b3lyp quantum chemistry is used to study the electronic structure of complex n-hexane with aluminosilicate clusters ZSM-5 and Н-ZSM-5 in the supermolecule model. It is established that when charge of the complex q = 0 and the environment of the Al atom has a tetrahedral structure, hydrogen abstracted from n-hexane forms H2O with an OH group from the Al environment. When the Al atom, a strong Lewis-type acid center, is in trigonal hybrid state sp2, it is capable of abstracting a hydrogen hydride ion from the isomer, which, when attached to an aluminum atom, changes its hybrid state to sp3. The speed of the hydrocracking of isomers α depending on the pore size are compared to the rate depending on electrophilicity of isomers ω, calculated via DFT b3lyp/6-311g(d,p). It is shown that dependences α on the isomer branching parameter and index of electrophilicity ω are identical, but the interpretation of the results differs. In the first case, there is a change in pore sizes; in the second, the electronic structures of the aluminosilicates and the isomers themselves change.

Methods are examined for estimating the Hildebrand solubility parameter of a mixture of organic solvents using the characteristics of their structural elements. A procedure is proposed for calculating the solubility parameter for mixtures of solvents differing in composition and structure depending on the ratio of their components. These results enable us to predict the optimal solvent mixture composition for polymers with a known Hildebrand solubility parameter. The proposed method permits us to estimate the solubility of complex mixtures of hydrocarbons of petroleum origin such as the tar obtained as the vacuum residue of oil distillation when it is used as a polymer solvent. 1H NMR analysis results were used to determine the structural elements of a tar and calculate its Hildebrand solubility parameter.

Experiments on hydroconversion of petroleum tar, tire rubber, and their mixtures in the presence of a nanosized catalyst precursor, performed using thermal gravimetric analysis, showed that the thermodynamic characteristics of the mixture degradation depend on its rubber content. The activation energy Еа calculated from the rate equations using TGA data appeared to be the lowest for the mixture containing 70 wt

A method for calculating the Hansen solubility parameter of organic solvents by taking the sum of the contribution of each structural element of a solvent molecule is considered. Two variants are proposed for calculating this parameter. Comparison of the calculated and experimental values of these parameters fora 20 organic compounds of different classes showed satisfactory accuracy of the proposed calculation procedure. Feasibility was demonstrated for the use of this method of selecting solvents for dissolving polymers as well as for calculating some physicochemical characteristics of solvents such as molar volume, enthalpy of formation, and Gibbs free energy.

The relationships in formation of the hydrocarbon composition of the hydrogenizate fraction in polyethylene and petroleum tar hydroconversion were studied. The catalytic hydroconversion of tar, polyethylene, and their blend was performed at 450°С and a pressure of 7 MPa in the presence of nanosized MoS 2 catalyst. A synergistic effect in hydroconversion of a polyethylene–tar blend was revealed. The composition of hydrogenizate fractions was substantiated using the results of quantum-chemical and thermodynamic calculations of structures simulating the hydroconversion products of tar, polyethylene, and their blend. Procedures were suggested for calculating the structural parameters (total number of atoms, total number of all types (single, double, triple) of chemical bonds, structure unsaturation parameter) of fractions of liquid hydroconversion products, based on the elemental composition data. A classifier systematizing the hydrogenizate fraction components and allowing prediction of some physical properties of the fractions (density, solubility) from the degree of structure unsaturation was constructed.

The influence of the phase composition of the dispersed molybdenum catalyst on the transformation of high-molecular-mass components (resins and asphaltenes) in the course of hydroconversion of heavy petroleum feedstock was studied. Suspensions of catalyst particles were prepared from inverse emulsions of aqueous solutions of the precursor, ammonium paramolybdate, directly in the feed in the course of hydroconversion ( in situ ), or the catalyst suspension was synthesized in advance ( ex situ ) and then was added to the feed. The vacuum residue from petroleum distillation and heavy crude were used as the feedstock. Experiments were performed in a flow-through reactor under the conditions of hydroconversion with the addition of a sulfur donor to the feed. Catalyst particles with different ratios of the Mo sulfide and oxide phases were prepared ex situ . With an increase in the МoS 2 content of the dispersed catalyst, its activity in inhibition of chain reactions of thermal cracking, yielding resins, asphaltenes, and coke, increases. The conversion of the >500°С fraction in the presence of the catalyst decreases; this is probably due to saturation and neutralization with active hydrogen of primary radicals that are generated in the course of thermal degradation, initiate the chain reaction of thermal cracking, and favor its propagation.

The relationships of the two-step regeneration of the slurry-phase hydroconversion catalyst separated as a component of a solid powder from the vacuum residue after distillation of the product obtained by hydroconversion of a mixture of petroleum tar and polymer waste were studied. The low-temperature oxidation of Mo sulfides was studied as the first step. High degree of oxidation of Mo sulfides to oxygen compounds of molybdenum in the highest oxidation state was reached at 250–400°С depending on the heat treatment time (from 30 to 150 min). The efficient oxidation is confirmed by the degree of transfer of the Mo oxides into an ammonia solution in the second step, leaching of the oxidation products obtained in the first step. The low-temperature oxidation of the catalyst concentrate as a component of the toluene-insoluble residue from the hydroconversion of a mixture of petroleum tar and polymer waste allows virtually complete (>95

The study investigates the activity of in situ synthesized suspensions of nickel-promoted molybdenum disulfide particles in the hydroconversion of crude oil vacuum residues. The catalyst suspensions were prepared in situ from water-in-oil emulsions of aqueous solutions of precursors, specifically ammonium paramolybdate and nickel nitrate. The catalytic tests were carried out in a flow-type reactor at 430°C, WHSV 1 h –1 , and 7 MPa hydrogen, with the Mo:Ni atomic ratio in the catalyst particles ranging from 1:0.022 to 1:1.43. The XRD of the toluene-insoluble solids (TIS) extracted from the hydrogenates identified sulfides such as MoS 2 , Ni 3 S 4 , and Ni 3 S 2 in the dispersed catalyst. Increasing the nickel content in the catalyst favored its hydrogenation activity, which was indicated by an enhancement in the feed conversion, an increase in the content of paraffins and naphthenes, and a decrease in the sulfur content in the distillates and TIS derived from the hydrogenates. The conversion of high-molecular-weight feed components (resins, asphaltenes, and heavy aromatics) was enhanced as a result of the nickel promotion of the dispersed MoS 2 .

A thermodynamic analysis of the reactions for the conversion of dimethyl ether into valuable products of the gas and oil industry and of propylene, formaldehyde, and 1,3-butadiene in particular was carried out. The temperature dependence of the equilibrium composition in the reaction for the production of 1,3-butadiene from dimethyl ether was determined. Calculation of the temperature dependence of the equilibrium composition in the reaction of propylene with formaldehyde with the formation of 1,3-dioxane, 1,3-butanediol, and 2-buten-1-ol showed that the main product at equilibrium is 2-buten-1-ol.

The study relates to the problem of selecting a solvent for organic polymers during their chemical processing. Based on the method of Askadsky, simple schemes were proposed for calculating the solubility parameter of small molecules and polymeric materials using the structural elements of molecules. On the example of small molecules and polymers it was shown that the constructed methods are not inferior in accuracy to methods of Askadsky, Small, and Van Krevelen. The proposed schemes make it possible to calculate the solubility parameter and find acceptable solvents for a polymer material with a known value of the solubility parameter. The schemes were tested on specific examples and the possibility of their application for the selection of a solvent was demonstrated.

The paper investigates the sulfidation of the precursor of a dispersed molybdenum catalyst consisting of 190–500 nm particles in the hydroconversion of crude oil vacuum residue. The experiments were carried out in a flow-through autoclave reactor system at a hydrogen pressure of 2.5 MPa, in the temperature range of 380–440°C, and with a reaction time of 50–150 min. The catalyst sulfidation was demonstrated to result from a reaction with H2S, which is formed from the thermal decomposition of petroleum feedstock. The sulfidation at 380–400°C is a fairly slow process. At higher hydroconversion temperatures (420–440°C), the H2S concentration in the gas phase grows. However, the formation of compaction products creates a diffusion barrier for H2S transportation to the surface of the catalyst particles and, thus, prevents the precursor from being converted completely to the sulfide form. To enhance the degree of sulfidation, it is preferable to use sulfiding agents that ensure that hydrogen sulfide is formed under the hydroconversion conditions of heavy petroleum feedstock.

A procedure for the construction of an approximating particle-size distribution function of a dispersed phase using a dynamic light scattering method was proposed. This procedure makes it possible to pass from the experimental spectrum in the particle size–intensity coordinates to theoretical particle size–number of particles and particle size–weight of particles spectra and obtain additional data on the nature of the particle size distribution. The algorithm of the calculation method was presented and illustrated by particular examples.

The practical and theoretical aspects of the conversion of sulfur-containing components during the hydroconversion of heavy oil feedstock in the presence of nanosized MoS2-based catalytic systems are considered. Thermodynamic calculation of the temperature dependences of the equilibrium composition of the products of hydrogenation reactions of sulfur-containing compounds demonstrated that thiophene is the most stable product in a wide temperature range. Quantum-chemical techniques have shown that chemisorption of a hydrogen molecule on valence-unsaturated Mo atoms brings about the breaking of the H–H bond, migration of H atoms to other valence-unsaturated Mo atoms, as well as to S atoms. The study of the interaction of the Н2S molecule with the Mo2S4 and Mo3S6 clusters showed that the chemisorption of Н2S occurs on the valence unsaturated Mo atoms, followed by the abstraction and migration of the Н atoms over the cluster surface, and the unsaturated S atom plays the role of a donor, hydrogen carrier. It was shown that sulfur-containing compounds (mercaptans, thiophene, and dibenzothiophene) are also chemisorbed through S atoms on valence-unsaturated Mo atoms located on the faces of MoS2 clusters.