An analysis of the phase behavior of binary systems is presented, including one of the representatives of aromatic alcohols (phenyl ethanol) and two potential extractants intended for use in the supercritical fluid (SCF) state. The study of the phase state of the thermodynamic systems “CO2–benzyl alcohol” and “propane–benzyl alcohol” in the near-critical region of the state has been carried out using a high-pressure optical cell. For the first time, data on phase equilibria of the “propane–benzyl alcohol” system have been obtained. The states of different phases are fixed.

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.

The phase behavior of binary systems containing organic components (phenol and acetone) and potential extractants (carbon dioxide and propane–butane mixture), which were proposed to be used in the supercritical state to treat the industrial wastewater from PAO Kazanorgsintez, is analyzed. The phase behavior of the CO2–acetone thermodynamic system in the near-critical region (313 K) is studied using a high-pressure optical cell. In this binary system, various phase states are detected, including areas of critical opalescence and complete miscibility. Supercritical fluid extraction (SFE) is investigated in treating a model aqueous solution of phenol and acetone with the concentration corresponding to industrial wastewater.

The isobaric heat capacities of acetone and its binary aqueous solutions were measured using a heat capacity meter (IT-s-400). The measurements were performed at temperatures from 323.15 to 453.15 K and pressures below 19.6 MPa for acetone and at temperatures from 348.15 to 473.15 K and the same pressures for its solutions, at concentrations of 2.5, 3.5, and 5 wt

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.

Представлен анализ фазового поведения бинарных систем, включающих органические компоненты (фенол и ацетон) и потенциальные экстрагенты (диоксид углерода и пропан-бутановая смесь), которые предполагаются использовать в сверхкритическом состоянии для очистки промышленного водного стока ПАО «Казаньоргсинтез». Проведено исследование фазового поведения термодинамической системы «CO2—ацетон» в околокритической области состояния (313 K) с использованием оптической ячейки высокого давления. Зафиксированы различные фазовые состояния, включая области критической опалесценции и безграничного смешивания для этой бинарной системы. Приведены результаты использования метода сверхкритической флюидной экстракции для очистки модельного водного раствора фенола и ацетона с концентрацией, соответствующей промышленному стоку. An analysis of the phase behavior of binary systems that include organic components (phenol and acetone) and potential extractants (carbon dioxide and propane-butane mixture), which are supposed to be used in the supercritical state to treat the industrialwastewater runoff of «Êazanorgsintez» PJSC, is presented. The study of the phase behavior of the thermodynamic system «CO2—acetone» in the near-critical region of the state (313 K) was carried out using a high-pressure optical cell. Various phase states are fixed, including areas of critical opalescence and boundless miscibility for this binary system. The results of using the supercritical fluid extraction method for purification of a model aqueous solution of phenol and acetone with concentrations corresponding to industrial waste are presented.

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 study performed on the supercritical aqueous oxidation of organic compounds in the water runoff of Nizhnekamskneftekhim PJSC, which was formed at the stage of epoxidation of propylene with ethylbenzene hydroperoxide during the joint production of propylene and styrene oxide, as well as run-off at PJSC "Kazanorginsez", when obtaining phenol and acetone from "Bisphenol-A" plant. The article studies a continuous operation mode on a flow reactor with induction heating (the drain from PJSC "Nizhnekamneftekhim") and periodic on coming from PJSC "Kazanorginsez". It was identified that close to complete oxidation in the presence of heterogeneous catalysts was achieved in a continuous mode at a temperature of 823 K and an excess of oxygen equal to 4.

Представлены результаты сравнительного анализа показателей ключевых факторов механизма увеличения нефтеотдачи пластов с использованием газов в сверхкритическом флюидном состоянии, применительно к диоксиду углерода и пропану (пропан/бутановым смесям). Вышеотмеченные факторы, как предмет рассмотрения, включают: растворяющую способность сжатых газов по отношению к нефти и ее компонентам; фазовое поведение бинарных систем, включающих обозначенные вытесняющие агенты и углеводороды нефти; критические параметры бинарных систем I–II типов фазового поведения; сжимаемость диоксида углерода и пропана в условиях осуществления процесса вытеснения нефти в рамках третичной нефтедобычи; вязкость сред, участвующих в обсуждаемом процессе и наконец, набухание нефти в результате ее насыщения газом. Приведены результаты экспериментальной реализации процесса экстракционного извлечения нефти, реализованного в сверхкритических флюидных условиях с использованием в качестве экстрагента диоксида углерода в одном случае и пропана в другом. Установлено, что пропан и пропан/бутановые смеси в сопоставлении с СО 2 имеют трех и более кратное превосходство в растворяющей способности по отношению к компонентам нефти в условиях процесса вытеснения; чаще формируют с компонентами нефти предпочтительные для процесса ее извлечения системы с I–II типом фазового поведения; мощность компрессора, затрачиваемая на сжатие диоксида углерода и метана, почти в три и более раза, соответственно, превосходит ту, что необходима при сжатии пропана и, наконец, пропан в условиях вытеснения нефти обладает существенно меньшей вязкостью, что в совокупности указывает на предпочтительность пропана и пропан/бутановых смесей в процессе вытеснения нефти в рамках процесса третичной нефтедобычи.

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 biodiesel fuel synthesis process is implemented in a batch plant by the transesterification of shea (Karite) and palm oils in an ethanol medium under supercritical fluid conditions in the temperature range 623–673 K and an alcohol-to-oil molar ratio range of 30 to 42 at a pressure of 30 MPa for 30 min. Data on the determination of the kinematic viscosity and composition of the resulting products and the feedstock conversion are obtained; and the optimal reaction conditions are found.

The results of comparative analysis for the key factors of the mechanism of oil-recovery enhancement with the use of gases in a supercritical fluid state as applied to carbon dioxide and propane (propane/butane mixtures) are presented. The above-mentioned factors as a subject of consideration incorporate the dissolving ability of compressed gases with respect to oil and its components, the phase behavior of binary systems containing the mentioned displacing agents and oil hydrocarbons, the critical parameters for the binary systems of fluid-phase behavior types I–II, the compressibility of carbon dioxide and propane under oil-displacement process conditions in tertiary oil production, the viscosity of the media participating in the discussed process and, finally, the swelling of oil as a result of its saturation with a gas. The results of experimental implementation under supercritical fluid conditions are given for an extraction oil-recovery process with carbon dioxide as an extragent in one case and propane in the other case. It is established that propane and propane/butane mixtures are three or more times superior to CO 2 in dissolving ability with respect to oil components under displacement-process conditions; that they more often form systems of fluid-phase behavior types I–II with the oil components, which is preferable for the process of its recovery; that the compressor power spent on the compression of carbon dioxide and methane is threefold or more higher than for propane; and, finally, that propane has a much lower viscosity under oil-displacement conditions. In sum, propane and propane/butane mixtures are preferable for use in the oil-displacement process within the framework of tertiary oil production.

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.

В установке периодического действия проведен процесс получения биодизельного топлива путем переэтерификации масла дерева Ши (Карите) и пальмового масла в среде этанола в сверхкритических флюидных условиях в интервале температур 623-673 K при давлении 30 МПа в диапазоне мольного соотношения «спирт-масло» 30-42 и времени 30 мин. Получены данные по определению кинематической вязкости образующихся продуктов и их составу, а также по конверсии исходного сырья, и установлены оптимальные условия осуществления реакции. The results of an experimental study of the process of obtaining biodiesel fuel by transesterification of Shea (Karite) and palm oils carried out in ethanol under supercritical fluid conditions on a batch unit using preliminary ultrasonic emulsification of the reaction mixture are presented. The studies were carried out in a temperature range of 623-673 K at a pressure of 30 MPa, a range of «alcohol-oil» molar ratios of 30-42, and a reaction duration of 30 minutes. Preferred reaction conditions have been established. The results of an experimental study of the kinematic viscosity of samples of initial oils and the product of the transesterification reaction The results of an experimental study of the kinematic viscosity of samples of initial oils and the product of the transesterification reaction are presented.

THE PURPOSE. The purpose of the work was to systematize the results of the work of domestic and foreign authors on the thermophysical properties of media and substances involved in the process of obtaining biodiesel fuel. METHODS. To measure the isobaric heat capacity, the predominant use is given to the methods of heat-conducting and scanning calorimeters, the measurement of the thermal conductivity by the heated filament method. Kinematic and dynamic viscosities are measured, respectively, on standard glass viscometers at atmospheric pressure and by the drop weight method. RESULTS. The results of a study of a wide range of thermophysical properties of thermodynamic systems involved in the process of obtaining biodiesel fuel under supercritical fluid conditions are presented. Attention is paid to the density, isobaric heat capacity, thermal conductivity, dynamic and kinematic viscosity of both the feedstock and the resulting biodiesel fuel, presented in a wide range of temperature and pressure changes, including nearcritical, as well as taking into account the thermal effects caused by the dissolution and change in the structures of substances under the influence of fluid reagent. CONCLUSION. The presented data will be necessary at the stages of designing and scaling a particular technology for the production of biodiesel fuel, both on a laboratory scale and at an industrial level.

The extraction of valuable components (methyl phenyl carbinol, acetophenone, ethylbenzene, phenol, propylene glycol) from industrial wastewater formed during styrene–propylene oxide coproduction by the hydroperoxide method at PAO Nizhnekamskneftekhim was used as an example to formulate and discuss approaches to increasing the efficiency of the extraction process performed under supercritical fluid conditions beyond the binodal for the systems desired component–extractant with type I and II phase behavior. The assumptions were experimentally confirmed by studying the extraction of methyl phenyl carbinol and phenol from their aqueous solutions with such extractants as carbon dioxide in the liquid and supercritical fluid state and also a supercritical propane/butane mixture. The phase equilibrium of the thermodynamic system propane/butane–propylene glycol was experimentally investigated at 403, 423, and 443 K.

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.