The oxidation of the “water-phenol-acetone” system, simulating the organic component of the concentrated water runoff from the Bisphenol-A plant of PJSC Kazanorgsintez, was experimentally studied in the temperature range of 523÷873 K, pressure 25 MPa, duration 2÷4 min in continuous mode. Air oxygen taken with excess coefficients equal to 10÷30 was used as an oxidizing agent. The composition of the oxidation reaction product, the indicator of chemical oxygen demand, the pH of the initial sample and reaction products, and the conversion were determined. A decrease in the initial organic compounds in the model runoff has been established.

This paper reports new results from studies of the isobaric heat capacities of OMEGA-3 “950” fish oil provided by SOLGAR INC (USA) at high temperatures and high pressures. The measurements were carried out on a differential scanning calorimeter (ITs-400) with an automatic data acquisition system in the temperature range from 298.15 to 473.15 K and at pressures from 0.098 to 39.2 MPa. The coverage factor for the 95% confidence level for a two-way coverage interval is assumed to be 2. The expanded measurement uncertainty of heat capacity is estimated to be 2.4%, pressure is estimated to be 0.05% and temperature is estimated to be 15 mK. Experimental data on the fish oil isobaric heat capacity as a function of temperature and pressure are approximated by the correlation equation proposed in the work. At atmospheric pressure, the deviations between those calculated by the correlation equation and the current measured data on isobaric heat capacity are within the range of average absolute deviations (AAD) = 0.22% (standard deviation St. Dev = 0.28% and maximum deviation Max. Dev = 0.39%). Additionally, a comparison was made of the state parameters obtained during the experiment and the literature data at the studied parameters.

THE PURPOSE. The purpose of this work was to use the associated paradigm for a correct quantum-chemical description of non-catalytic and catalytic supercritical fluid processes of transesterification of triglycerides with alcohols and hydrolysis of triglycerides and to model a one-stage process for obtaining biodiesel fuel, carried out under supercritical fluid conditions with its subsequent scaling to the commercial level. METHODS. The Gaussian09 software product was used to describe quantum chemical studies. The process modeling was carried out using the ASPEN Plus® v2006 software product. The behavior of thermodynamic systems at high temperatures and pressures is modeled using "RK ASPEN EOS". For modeling processes carried out at low pressures, mathematical models UNIQUAC and UNIFAC-LL were used. The scaling of the process was carried out in the VMGSim program. RESULTS. The third part of the review focuses on the quantum-chemical modeling of the transesterification reaction carried out under supercritical fluid conditions. It is shown that taking into account the associative paradigm makes it possible to obtain calculated reaction rate constants that agree in order with the experimental values. And also an analysis was carried out and the results of modeling the process of obtaining biodiesel fuel and scaling it to a commercial level, with a capacity of up to 9000 tons / year, were presented. CONCLUSION. The conducted analysis showed that biodiesel fuel can be a competitive fuel in our and the world market.

THE PURPOSE. The presented work aims to analyze the realities and prospects for the use of working media in the production of biodiesel fuel, including the supercritical fluid state. METHODS. Methods for obtaining biodiesel fuel are considered, including the method of transesterification, as the most common, as well as methods of pyrolysis and the combined process of hydrolysis and esterification. RESULTS. Traditional (industrially used methods for producing biodiesel fuel), as well as methods involving supercritical fluid media at their core, are considered. Along with a description of the state of affairs on the issues under discussion in the world, the results of our own research carried out by the team of authors of this article are also presented. Attention is drawn to the prospects of ultrasonic emulsification of the reaction mixture and the use of heterogeneous catalysts in order to mitigate supercritical fluid conditions for the process of obtaining biodiesel fuel and save energy. The conditions for obtaining biodiesel fuel without free glycerol and converting it into a fuel component are also discussed. CONCLUSION. Transesterification carried out under supercritical fluid conditions provides significant advantages over the traditional process and, especially in terms of the possibility of using a variety of raw materials, including low-quality ones, facilitates the procedure for isolating the final product and, finally, makes it possible to switch from relatively small-scale implementations with batch reactors to high-performance plants with flow reactors.

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 heat capacity at a constant pressure of the anthracene - supercritical propane-butane system was measured in the temperature range 343-473 K and pressures up to 19.6 MPa. The studies were carried out on the experimental setup that implements the method of scanning calorimetry. The combined expanded uncertainty of heat capacity measurements at a confidence level of 95% with a coverage factor of k = 2 is estimated at 2.8%. The results of measuring the heat capacity at a constant pressure of the mixture were used to calculate the enthalpy of the mixture.

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.

By quantum-chemical simulation using DFT method with B3LYP density functional and basis 6-311++g(df, p) in the implementation of the program Gaussian16 and subsequent comparison with calculations data, obtained by using density functional wB97XD/6-311++g(df, p), mechanism of reactions of transesterification and hydrolysis of fatty acid triglycerides, carried out under supercritical fluid conditions has been investigated.The energy characteristics of the elementary acts of potential steps for Supercritical Fluid (SCF) conditions has been calculated, their thermochemical analysis has been given, the rate constants of elementary acts for the temperature range 300-623 K has been investigated.It is shown that under supercritical fluid conditions, transesterification and hydrolysis of fatty acid triglycerides with dimer and trimer associates of alcohol and water in various combinations can proceed by one-step and two-step mechanism.

The reaction of transesterification of rapeseed oil in ethanol under supercritical fluid conditions in the 320-380 ϵC temperature range, under 30 MPa pressure, for ethyl alcohol to rapeseed oil molar ratios of (6-20):1 was studied experimentally. Dependencies of kinematic viscosity of the reaction product on the temperature, molar ratio of the starting reagents, and duration of reaction implementation were obtained. A correlative dependence that allows calculation of the content of ethyl esters of fatty acids in the transesterification product is proposed using experimental data on the kinematic viscosity values of the reaction product.

Noncatalytic and catalytic transesterification of rape oil were studied in an ethanol medium under supercritical fluid conditions, ultrasonic effect, temperature range from 623 to 653 K, 30 MPa, and with 12: 1 and 18: 1 alcohol to oil mole ratios. An effect of heterogeneous catalysts on the reaction rate was defined. Correlation dependence between the amount of fatty acid ethyl esters in biodiesel fuel and kinematical viscosity of the reaction product was determined.

In Europe, rapeseed is a renewable raw material which has been widely used for the production of biodiesel by various processes. The transesterification reaction of rapeseed oil with ethanol to biodiesel in supercritical fluid conditions was investigated using several heterogeneous catalysts and preliminary ultrasonic emulsification of the reaction mixture, to run the reaction at mild conditions. Phase equilibrium of fatty acids in supercritical ethanol was study to determine the operating condition in supercritical states. Transesterification experiments were carried out under a pressure of 30 MPa, with ethanol to oil molar ratio (in the range of 12:1-20:1), temperature (623 K to 653 K), and the catalyst loading level and type were the main parameters. The most important characteristics of Al2O3 support catalyst and the impregnation method with aqueous solution of metal nitrates are also described. Yields of Fatty Acids Ethyl Ester (FAEE) are reported for different ZnO/Al2O3, MgO/Al2O3, SrO/Al2O3 catalysts in different experimental conditions. The higher yield of 97.46% was obtained under the optimal conditions 623 K, 30 MPa, 12:1 ethanol/FAEE molar ratio, with SrO/Al2O3 (2 wt.% SrO) impregnated catalyst. (C) 2016 Elsevier B.V. All rights reserved.

Several biodiesel fuel samples produced from rapeseed oil by the noncatalyzed transesterification reaction with supercritical ethanol at various temperatures from (593 to 653) K and molar ethanol to rapeseed oil ratios from (6:1 to 20:1) were used to measure kinematic viscosity. Measurements were made using the capillary viscometer (VPZ-2, Labtex Corn., Moscow). The combined expanded uncertainty of the kinematic viscosity measurements at the 95 % confidence level with a coverage factor of k = 2 is estimated to be 0.35 %. All measurements were made at temperature of 313.5 K (ASTM D445) and at atmospheric pressure. The effect of fatty acid ethyl esters (FAEEs) content on the kinematic viscosity of biodiesel fuel samples at 313.15 K was studied. The correlation between the FAEEs concentration in biodiesel fuel samples and their measured kinematic viscosity at 313.15 K was found. The derived correlation between the kinematic viscosity and the FAEEs contents allows controlling the progress of the rapeseed oil transesterification process with supercritical ethanol.