Albina D. Badikova

1. Asphaltenes represent the heaviest and most polar fraction of crude oil, insoluble in lower n-alkanes but soluble in aromatic solvents such as toluene. These high-molecular-weight polycyclic com...

This work presents the results of kinetic study of thermocatalytic degradation of decalin, acting as a model compound of cycloalkanes characteristic for the composition of heavy oil residues. The kinetic scheme of the process based on elementary stages including formation and subsequent transformation of primary molecular products was proposed and substantiated for the first time. HYmmm zeolite modified with sodium tetrachloroferrate was used as a catalytic system. The dynamics of product formation was quantitatively analyzed by chromatography-mass-spectrometry and gas chromatography to determine the dependence of the molar fraction of decalin and its derivatives on the contact time with the catalyst at 550°C. It was found that the process proceeds through the formation of primary molecular products: naphthalene, butylcyclohexane, 1-methyl-2-propylcyclohexane and 1,2-diethylcyclohexane, which are intermediate compounds and undergo further transformations to form gaseous hydrocarbons C₁–C₄, components of gasoline and kerosene-gasoil fractions. A reaction mechanism including the formation of a catalytically active complex of decalin with the catalyst and its subsequent transformations by several routes was proposed. The applied kinetic approach allowed to adequately describe the experimental data and to determine the rate constant of the process (k = 0.42±0.02 s^–1). The obtained results can be used for prediction of selectivity of thermocatalytic processing of heavy oil feedstock and optimization of technological parameters.

RATIONALE: At main pipeline transport facilities, the entry of harmful chemicals into the air of the working area can negatively affect the body of workers. The absence in the existing regulatory documents of clearly formulated criteria for the selection of specific harmful chemical compounds to control their content, especially if they are a multicomponent mixture, introduces certain difficulties in identifying pollutants in the air of the work area. The presence of criteria will allow the employer to correctly draw up a production program, the frequency of laboratory tests to obtain more objective and reliable information about the potential harmful effects of chemicals on workers and timely take measures to prevent their negative effects. AIM: Justification of the list of harmful substances for analytical monitoring of their content in the air of the working area of main pipeline transport facilities for oil and petroleum products. MATERIAL AND METHODS: Qualitative and quantitative analysis of the air in the working area was carried out at 12 oil pumping stations and 5 oil product pumping stations located in Russia. RESULTS: Using chromatography-mass spectrometry, the composition of the gas-air environment formed as a result of oil evaporation was determined, which made it possible to determine a list of harmful chemicals for further planned analytical monitoring of their content in the air of the working area.CONCLUSION: Sampling should be carried out in places with the highest probability of gas emissions into the air. When transporting oil, it is necessary to establish strict analytical control at workplaces over the content of aliphatic saturated hydrocarbons C2-C10, dihydrosulfide mixed with hydrocarbons, benzene in the air, when pumping petroleum products - benzene, gasoline or kerosene, i.e. depending on the type of petroleum product transported.