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The sugar industry in Russia plays a huge role in ensuring the country’s food security and is a strategic industry. Of the 90 sugar factories in Russia today, a third of the factories are closed due to unprofitability associated with the high cost of sugar production due to low feed capacity. The raw material for sugar production is sugar beet, mainly domestically produced. The locations of most sugar factories are small municipalities, for which they are the town-forming enterprises. For the revival of closed sugar factories, it is necessary to increase their capacity, which is difficult to do due to the fact that in the diffusion section of each sugar factory there is one large-sized imported diffusion apparatus of a mechanical type, which does not allow increasing capacity in any other way than purchasing a new, more high-performance expensive imported diffusion apparatus of a mechanical type. In the current conditions of uncertainty and disruption of trade relations with other countries, new suppliers of high-performance diffusion apparatus are needed in Russia itself, the apparatus of which would at least not be inferior to the Western apparatus. The Russian company Ingehim has developed a diffusion pulsating apparatus (DPA) without mechanical movable transporting devices, which reduces energy consumption, operating costs and lowers quality requirements for sugar beet chips. The test results obtained using an experimental unit showed a higher quality of the diffusion juice. The lightness of the juice was found to be much higher compared to juices produced in conventional diffusion apparatus, and the juice purity was found to be 5% higher at a comparable solids content, resulting in an additional amount of sugar produced per year, allowing for a faster return on investment.

Chicory roots are a valuable source of inulin and other healthy nutrients. The most common direction of their industrial processing is instant chicory powder production. Extraction is the main process in the production. Conventional extraction methods, which include maceration, percolation and extraction in a screw extractor, have a number of significant drawbacks, including high capital and operating costs, low quality of the resulting extract, complexity in repairing equipment, short overhaul life, etc. The purpose of the present study was to assess the technical feasibility of increasing extraction process efficiency through using continuous pulsating extractors (CPE) developed by the Ingehim company, in which a non-stationary, countercurrent mode of interaction of raw materials with the extractant is incorporated. Testing of engineering solutions implemented in CPE was carried out at a pilot pulsating unit (PPU). For extraction, roasted and crushed (5–20 mm) chicory roots from one of the operating chicory factories were used. The ratio chicory : water during extraction was 1 : 4.5, which is 1.5–2.5 times lower than in conventional extractors. A lower extraction temperature (up to 85°C) combined with a shorter extraction time (up to 1 hour) may help retain more inulin and other nutrients as compared to conventional methods. The results of the study at the PPU under these conditions confirmed the high yield of water-soluble solids (up to 98%) without additional grinding. A scheme for the modernization of a chicory factory equipped with the most common percolation extraction equipment having a feed capacity of 400 kg/h is proposed through using CPE. 3D images of the proposed modernization are shown. A comparative assessment of energy consumption for extraction using different methods is given. The results of the study indicate the capability and high efficiency of CPE for extracting chicory, which is confirmed by a decrease of up to 3.6 times in the total specific energy consumption for obtaining 1 kg of instant chicory powder compared to conventional extractors. Low capital and operating costs determine the prospects for using CPE for the modernization of existing chicory factories or the creation of new energy-efficient factories.

A molecular-statistical method for simulating the process of pervaporation on hybrid silicon oxide membranes is proposed. This method is a development of the control volume method. Models of three membrane samples with different densities and pore sizes were obtained. These samples were used for the molecular-dynamics simulation of pervaporation of a 95 mol % aqueous solution of ethanol at a temperature of 343 K. It is shown that the membrane is selective with respect to water; the component flow is found to exponentially depend on the pore size.

Results of experimental investigation of pervaporation dehydration of ethanol and isopropanol by HybSi membranes at concentrations of organic component in the feed in the range from ~50 to ~99wt%, feed temperatures 60, 70 and 80°C and permeate pressures 5 and 20mm Hg are presented. The experimental data demonstrate a nonmonotonic dependence of separation factor on water concentration in the feed with maximum value of separation factor reached at water concentration in the feed of several percent for both ethanol dehydration and isopropanol dehydration. Values of both total permeate flux and separation factor for the isopropanol dehydration case are higher than for the ethanol dehydration case. Results of the experimental investigation are compared with similar results of other researchers obtained for pervaporation dehydration of ethanol and isopropanol by membranes coated with a selective layer made of silica-based and zeolite-based materials. Based on the “solution-diffusion” concept, a mathematical model is developed for the pervaporation process, which includes three parameters, two of which are permeability coefficients for pure components and the third parameter defines “active pores fraction”. Use of the model can lead to essential reduction of the number of pervaporation experiments needed for designing a pervaporation pilot plant as well as assist in determining optimum operating conditions of the pervaporation process. Results of calculations carried out with use of the proposed model are compared versus results of experimental investigation of pervaporation dehydration of ethanol and isopropanol by HybSi membranes, pervaporation dehydration of glycerin by HybSi membranes (of other researchers) and pervaporation dehydration of ethanol by NaA zeolite-based membranes (of other researchers). Results of calculations agree reasonably well with all considered experimental data. Additionally, the model allows determining the optimum thickness of the selective layer of HybSi membranes.

The paper describes the problem of hazardous gas propagation when discharged through technological vents. Drawbacks of the standard methods in force have been identified. Aims and Objectives To develop a math model that would allow adequate forecast the character of propagation in the atmosphere of hazardous gas clouds, when discharged through vents; also, to assess the influence of stability of atmosphere on these processes. Methods Numerical modeling. Results Calculation results obtained using the developed model and by other methods are given against experimental data. Conclusion The results of studying influence of atmospheric stability and wind velocity on the dynamics of formation and dispersion of the discharged hazardous gas clouds have been analyzed.

The proposed mathematical description of the key parameters and conditions of the processes of emptying the processing equipment by releasing dangerous gases from it with the account of non-stationarity ofthe processes allowed to obtain equations for determination of duration ofthe gas efflux from the equipment before its full emptying in cases of subcritical and critical efflux velocities. The proposed two methods of determining the time of emptying the equipment, through reducing mass ofthe gas (x m ) and through pressure dumping (x P ), give divergences in the results about 1-2 %. The obtained analytical dependences allow determining flow parameters at the stack tip (pressure, mass flow rate, temperature, density, speed) depending on time. The use of these dependences as boundary conditions for calculation of gas releases in such software packages as Fluent [1,6], allows for adequate calculating the process of propagation ofthe air-gas mixture in the atmospheric surface layer at releasing dangerous gases from the industrial tanks and vessels in cases of shutdowns of technological systems for repairs or at emergencies.

Conventional methods of regeneration of diethylene glycol used as an absorbent for natural gas dehydration at complex gas treatment plants in the Russian gas fields are analyzed. An alternative method of regeneration by pervaporation using tubular ceramic membranes coated on the inside with the HybSi material is proposed. Experimental study of pervaporation dehydration of diethylene glycol in concentration ranges 97–99.5 wt% and 93.5–99.5 wt% corresponding to saturation levels 2.5 wt% and 6.0 wt%, respectively, is carried out in the temperature range 70–90 °C and vacuum pressure range 5–30 mm Hg. Increase in saturation level from 2.5 wt% to 6.0 wt% leads to inessential increase in the required surface area of HybSi membranes. Results of the experimental study are compared with experimental results obtained by other researchers for SepraTek hollow-fiber polymer membranes. Losses of diethylene glycol through HybSi membranes are shown not to exceed losses at conventional stripping and to be lower by two orders of magnitude than losses through SepraTek membranes. Use of pervaporation instead of stripping for diethylene glycol regeneration leads to more than two-fold energy saving.

A computational model for a horizontally uniform atmospheric boundary layer accounting for various options of atmospheric stability is developed on the basis of Monin-Obukhov’s similarity theory. Numerical modeling of the atmospheric boundary layer is carried out using the Fluent package. For a turbulent closure, the standard k–e turbulence model with modified turbulence closure constants and an additional source term in the equation for k are applied. Cases of neutral, stable and unstable stratification are considered. The computational model allows preserving horizontal uniformity of vertical profiles of velocity, pressure, density, temperature and atmospheric turbulent viscosity which are set as boundary conditions at the domain’s inlet. The obtained model can be applied to modeling of propagation of hazardous gas clouds in the atmosphere over the terrestrial surfaces including surfaces filled with buildings.

The pervaporation dehydration of diethylene glycol using ceramic tubular membranes with a hydrophilic selective layer formed from HybSi material was experimentally studied. The experiments were carried out over the process temperature range of 70–90°C at pressures in the permeate part of membrane unit in the range of 5–30 mm Hg and at diethylene glycol concentrations in the range of 93.5–99.8 wt %. Dependences of the membrane surface area required for the dehydration of diethylene glycol over a predetermined range of concentrations on productivity, process temperature, and vacuum were determined.

Экспериментально исследовано первапорационное обезвоживание диэтиленгликоля с использованием керамических трубчатых мембран с гидрофильным селективным слоем из материала HybSi. Эксперименты выполнены в диапазоне температур процесса 70–90°C, давлений в пермеатной части мембранной установки от 5 до 30 мм рт. ст. и концентраций диэтиленгликоля 93.5–99.8 мас. %. Определены зависимости площади мембранной поверхности, необходимой для обезвоживания диэтиленгликоля в заданном диапазоне концентраций, от производительности, температуры процесса и вакуума.

An algorithm for calculating the vapor-liquid phase equilibrium for multicomponent gases is presented. A six-component gas mixture is considered. The algorithm for calculating phase equilibrium is based on the solution to the Soave-Redlich-Kwong equation of state for real gases. An iteration algorithm for updating phase equilibrium constants is used. The total vapor fraction is determined using the solution to the Rachford-Rice equation. The difficulties of developing such algorithms are considered in full detail. The derived solution is compared with results obtained in the commercial package HYSYS (version 3.2) when the Soave-Redlich-Kwong equation is also used.

Growing interest in small-scale, portable energy systems such as fuel cells has necessitated the development of small-scale fuel processing or reforming systems. Many fuel reforming systems require reliable heat sources as in some cases temperatures in excess of 600°C maybe required. Sub-millimeter combustors can provide such a heat source; however, a broader set of design rules are needed for constructing systematically engineered heat sources. In this article, experimental observations and computational fluid dynamics modeling results are presented for stable and steady confined flame structures within an alumina sub-millimeter combustor. Influence of inlet flow and thermal boundary conditions are evaluated through a parametric study. The inlet flow rates and relative gas composition, the thermal boundary conditions that include thermal conductivity of the walls, convection of heat to and from the walls, and radiation of heat energy through the walls all determine the position, structure, and temperature of the reacting fluid and combustor walls. The model shows the importance of radiative heat transfer in the formation of the steady-state flame structures within the microcombustor.

This paper discusses the development of a thermal model for heat transfer in the potential repository at Yucca Mountain, Nevada, USA. The model is based on separating the calculation of the emplacement drift from the surrounding mountain rock. When ventilation of the drift is considered, the heat generated by the waste package is removed from the drift by the ventilating air and conduction through the drift wall. The heat transfer path through the rock is of less importance than that through the ventilating air, allowing zero-heat flux boundary conditions to be applied on the drift wall. The finite-volume method is used to accomplish the numerical simulation; k-ε closure is used to model turbulence. Influences of such parameters as velocity of the ventilating air, thermal loading, and radiation heat transfer on the drift wall temperature are analyzed. It appears that radiation does not play an important role when ventilation is used, and does not significantly increase the drift wall temperatures.