An experimental setup was created to measure the solubility of substances in supercritical carbon dioxide by a dynamic method, including the possibility of adding a cosolvent to the main solvent: CO2. A new technique has been developed for determining the mass amount of supercritical carbon dioxide that has passed during the experiment, which is important in determining solubility. Experimental data on the solubility of diphenyl in supercritical carbon dioxide are obtained, which are in good agreement with the literature data, at various state parameters: temperature and pressure. The experimental setup will make it possible to obtain new experimental data in the future on the solubility of a wide range of substances in supercritical carbon dioxide as well as in supercritical carbon dioxide with various organic cosolvents.

The paper presents the results of impregnation of dried common pine (Pinus sylvestris) specimens with propiconazole using a supercritical fluid CO2 impregnation process carried out at a temperature of 338 K in the pressure range of 10–30 MPa. Within the framework of the formation of a database on the properties of the impregnation material required for the stages of modeling, optimization, and scaling of the impregnation process, an investigation was conducted of some thermodynamic properties of a propiconazole–carbon dioxide mixture in the supercritical fluid region of the state. The isomeric composition of propiconazole has been investigated, and it has been established that it represents a mixture of two isomers. The methods of thermogravimetric analysis and differential scanning calorimetry have been used to study the thermal characteristics of propiconazole. The paper presents the results of an experimental investigation of propiconazole solubility in supercritical carbon dioxide on the isotherms T = 338, 358, and 378 K in the pressure range of 10–30 MPa. The experimental data on solubility have been described using the Peng–Robinson equation of state and providing the pressure of saturated propiconazole vapors with the status of the second adjustable parameter in the calculation algorithm. The paper presents the results of an experimental investigation of the isobaric heat capacity of propiconazole at atmospheric pressure in the temperature interval of 313–573 K and of propiconazole–carbon dioxide mixture in the timperature interval of 313–473 K and the pressure range of 0.098–25.0 MPa.

The phase equilibrium of the propylene glycol–propane/butane system and the solubility of propylene glycol in a supercritical propane-butane mixture at temperatures of 403, 423, and 443 K are studied using a high-pressure optical cell. The results are described using the Peng–Robinson equation of state and the Mukhopadhyay and Rao mixing law.

In this work, we propose an alternative method for the utilization of sleepers, based on the use of a supercritical fluid extraction process. The preference for the implementation of a supercritical fluid extraction process for “extractable-extractant” systems exhibiting I–II types of phase behavior is given. On the example of supercritical fluid extraction of the impregnation material of spent wood railway sleepers, the efficiency of replacing the carbon dioxide participating as an extractant with a propane/butane mixture, which provide the desired change in the type of phase behavior in relation to such components of the impregnation material as phenol, anthracene and naphthalene is shown. The phase equilibria of thermodynamic systems involving carbon dioxide and a propane/butane mixture on the one hand and coal oil components such as phenol, anthracene, and naphthalene on the other are studied. The proposed method of processing spent railway sleepers allows you to select from it up to 97 % of the mass impregnation source material.

Исследована возможность выделения нефтепродуктов из нефтяных шламов с использованием процессов жидкостной и сверхкритической флюидной экстракции. Исходный нефтешлам содержит (здесь и далее - в мас. %) 30 воды, 5,9 механических примесей и 5,7 асфальтенов. Экстракция смесью пропана и бутана в соотношении 3 : 1 (мас. %) при 85-120 °С и давлениях 10 и 15 МПа позволяет получить нефтепродукты с существенно пониженными вязкостью и содержанием серы и воды. The possibility of extracting petroleum products from oil sludges using liquid and supercritical fluid extraction is studied. The initial content of water and solid residues in the sludge sample was 30 and 5.9 wt. %, respectively. If the 3: 1 (by weight) propane-butane mixture is used as extragent at 85-120 °С and 10-15 MPa, the petroleum product with substantially reduced viscosity and sulfur and water content can be obtained.

The prospects of using supercritical fluid medium for the extraction of oil products from tar sands are discussed. The results of an experimental study of the extraction process using propane-butane extractant (75% wt. propane + 25% wt. butane) in liquid (t = 80 °C, 100 °C, P = 5-10 MPa) and supercritical fluid (t = 140 °C, P = 5-10 MPa) states are presented. The results of quantum chemical simulation are presented in relation to the above process.

Abstract—The extraction of oil products from oil sludge with liquid and supercritical fluid processes is studied. The initial oil sludge contains 30, 5.9, and 5.7 wt % of water, mechanical impurities, and asphaltenes, respectively. The extraction, with a 3 : 1 (wt %) mixture of propane and butane at 85–120°C and pressures of 10 and 15 MPa, allows petroleum products to be obtained with significantly low viscosity and low amount of sulfur and water.

The synthesis of palladium and palladium–silver catalysts using supercritical fluid CO2-impregnation (static conditions) was studied. It was shown that the highest amount of metal is impregnated onto a support in a temperature range of 318–323 K and a pressure range of 19.0–23.0 MPa. The activities of palladium catalysts prepared according to the proposed procedure were comparable with those of currently produced industrial samples.

Results are presented concerning the studies on obtaining a heavy oil residue, its deasphalting and the impregnation of crushed carbonate stone with deasphaltizate. The heavy oil residue is obtained via the separation of extra-heavy crude oil using a steam thermal method. The deasphalting of the oil residue and the impregnation of crushed carbonate stone are carried out using a propane-butane solvent in the liquid and supercritical fluid state, respectively.

The process of wood drying is studied in supercritical (SC) CO2 and SC-CO2 containing 5 vol % ethanol at temperatures of 323, 343, and 353 K and pressures of 10, 20, and 30 MPa. It is established that 40–87% of moisture is removed from wood in the first cycle of drying. An increase in the duration of the decompression stage of the drying process decreases the number of cracks in the wood samples. The solubility of propiconazole is studied in SC-CO2 at 323, 343, and 353 K in the pressure range of 10–30 MPa using a dynamic method. Rather high saturation concentrations of (3–5) × 10–3 mol/mol CO2 are obtained, which indicates the potential benefits of using SC-CO2 as a solvent in wood impregnation with propiconazole. Continuous impregnation is achieved when impregnating wood with propiconazole from SC-CO2. The impregnation efficiency increases with increasing pressure and duration of the process.

Results from studying the supercritical fluid СО 2 -extraction regeneration of DN-3531 industrial nickel–molybdenum hydrotreatment catalyst in the temperature range of 323.15–383.15 K, at pressures of up to 30 MPa, and with modification of the basic extragent with such polar compounds as chloroform, methanol, ethanol, acetone, and dimethylsulfoxide (DMSO), are presented. The order of modifiers corresponds to the increase in the solubilizing ability of modified supercritical carbon dioxide (SC-СО 2 ) with respect to catalyst- deactivating deposits. With DMSO as the most efficient modifier, however, not only are deactivating compounds removed but nickel and molybdenum as well, considerably reducing the final activity of a regenerated sample. During extraction regeneration, the content of coke in the catalyst is reduced by two-thirds, while the specific surface area and the pore volume grow. The activity of the deactivated catalyst in dibenzothiophene hydrodesulfurization (HDS) and naphthalene hydrogenation grows by several hundred per cent after one-time SC-CO 2 treatment and is 2.5 times higher than for a sample regenerated using the traditional oxidative method.

ABSTRACT The authors present the results of investigation and experimental implementation of several processes: production of heavy oil residue and its deasphaltizing and impregnation of carbonate rock with deasphalted oil. Heavy oil residue has been produced during fractionation of highly-vicious oil by steam-thermal method. Deasphaltizing of oil-residue and impregnation of carbonate rock are implemented with the use of extraction and supercritical fluid impregnation processes with propane-butane solvent.

A comprehensive process for the deasphaltizing of heavy oil residue and subsequent treatment (impregnation using a solvent in the supercritical fluid state) of a carbonate macadam by bituminous compounds (deasphaltizate) is developed. The purpose is to improve the functionality of the material and, above all, to reduce its water absorption capacity. The process parameters are specified based on the newly obtained data on the thermal capacity of heavy oil residue and deasphaltizate. The results of the process of experimental implementation and the characteristics of impregnated macadam, including the water absorption capacity which decreased from 3.6 to 0.54%, are presented.