Research of Wheat Drying in a Microwave and Combined Filter-microwave Dryer

The aim of the conducted study is to determine kinetics of the complex effect of microwave energy supply and filter drying of the process of water release from the wheat layer. There is offered a combination of MW and filter drying. A special feature of this combination must be its more effectiveness and high speed of water elimination from surface layers of wet seeds and, as a result, the productivity increase of the drying way, decrease of specific energy consumption.There was determined the influence of the specific load of the material, radiator power on processes of microwave and filter-microwave drying of wheat seeds. There were compared microwave, filter-microwave and convective drying of seeds by parameters of specific energy consumption, drying speed.The specific energy consumption at microwave drying of seeds was 4 MJ/kg, at filter-microwave drying 3.8 MJ/kg that is lower than existent convective dryers. The speed of microwave drying changes from 0,5 to 3 %/min, filter-microwave – from 0.3 to 0.7 %/min. The speed is at the level of standard convective dryers.The conducted studies allow to recommend a new combined way of FMW drying of seeds with low energy consumption.Revealed features of heating and drying are possible to be used at developing industrial dryers.The base of experimental data is possible to be used for optimizing and determining effective conditions of MW and FMW drying

Modeling of complex oxide materials from the first principles: systematic applications to vanadates RVO3 with distorted perovskite structure

"Realistic modeling" is a new direction of electronic structure calculations, where the main emphasis is made on the construction of some effective low-energy model entirely within a first-principle framework. Ideally, it is a model in form, but with all the parameters derived rigorously, on the basis of first-principles electronic structure calculations. The method is especially suit for transition-metal oxides and other strongly correlated systems, whose electronic and magnetic properties are predetermined by the behavior of some limited number of states located near the Fermi level. After reviewing general ideas of realistic modeling, we will illustrate abilities of this approach on the wide series of vanadates RVO3 (R= La, Ce, Pr, Nd, Sm, Gd, Tb, Yb, and Y) with distorted perovskite structure. Particular attention will be paid to computational tools, which can be used for microscopic analysis of different spin and orbital states in the partially filled t2g-band. We will explicitly show how the lifting of the orbital degeneracy by the monoclinic distortion stabilizes C-type antiferromagnetic (AFM) state, which can be further transformed to the G-type AFM state by changing the crystal distortion from monoclinic to orthorhombic one. Two microscopic mechanisms of such a stabilization, associated with the one-electron crystal field and electron correlation interactions, are discussed. The flexibility of the orbital degrees of freedom is analyzed in terms of the magnetic-state dependence of interatomic magnetic interactions.Comment: 23 pages, 13 figure

Studying the Operation of Innovative Equipment for Thermomechanical Treatment and Dehydration of Food Raw Materials

The paper reports results of investigating innovative equipment for the integrated processing of food raw materials, which would make it possible to implement the local energy influence directly on the particles of a dispersed material, the near-boundary layer, the moisture retained in the product's solution or capillaries.The analysis of food raw materials processing techniques has been performed, their benefits and shortcomings have been identified. It was found that product quality, energy consumption and cost are mainly determined at the stages of thermal processing, drying.We have examined innovative equipment based on rotary thermosiphons for evaporating food non-Newtonian liquids. An experimental bench has been designed, and the procedure for studying the hydrodynamics of condensate motion in condensers of rotary thermosyphons of various structures has been devised. The experimental bench represents a model of the device with a rotary thermosiphon made of glass. The result of our study is the established rotational frequency, at which a condensate is locked by the centrifugal force for a branched condenser. Results from visualization of vapor-condensate movement have been presented.The innovative equipment for the evaporation of food non-Newtonian liquids under SHF radiation conditions has been investigated. Experiments involved food products and model systems. We have determined the degree of an increase in the concentration of non-aquatic components. Evaporation rate under conditions of SHF radiation is almost constant.The innovative equipment for drying fruit- and vegetable-based slices under conditions of IR radiation has been examined. An experimental bench has been designed and the research procedure has been devised. We have proposed the structure of an equation for calculating the mass transfer coefficient. The database of experimental findings has been generalized in the equation by similarity numbers. The equation makes it possible to calculate a mass transfer coefficient with error within ±15 %. The influence of IR radiation power on the kinetics of the process of drying fruit and vegetable slices has been determined. We have compared experimental data on slice drying under conditions of SHF and IR radiatio

Development of Power­efficient and Environmentally Safe Coffee Product Technologies

Based on the energy and environmental audit, analysis of material flows, energy conversion, emissions into atmosphere and lithosphere in the production of instant coffee was carried out.To raise energy efficiency and reduce environmental burden, innovative flow diagrams and equipment for waste processing and production of new coffee products have been developed.Experimental modeling was carried out: kinetics of microwave extraction of water-soluble substances and oil from coffee slurry; hydraulics of the extractant flow through cassettes of the microwave extractor. The experimental data were summarized in the form of a criterion equation.As a result of experimental modeling of the extraction kinetics, it was found that the duration of the process in a microwave field is approximately 20 times less than in a thermostat. The microwave field affects the extraction rate to a greater extent than the process temperature. The growth of microwave power results in a more than the two-fold rise of the yield of extractives from a coffee slurry.Specification of the microwave oil extractor was defined. The extractor sample was tested at a specific power of 180...240 W/kg in the mode of boiling extractant. Ethanol (93...96 % concentration) was used as an extractant. As a result of the tests, a high-quality coffee oil was obtained. It is characterized by a pronounced aroma, coffee taste and an intense dark brown color.Flow diagram of pre-extraction of coffee from slurry was worked out. Additional extraction of water-soluble extractive substances from coffee slurry increased the extract yield by 10...12 %. The temperature regime of extraction was significantly reduced plus duration and energy intensity of the process were reduced.An innovative flow diagram has been developed for the production of liquid coffee concentrate as a basis for coffee-based drinks ready for immediate use. The concentration of solids is 50...65

Development of the Design and Determination of Mode Characteristics of Block Cryoconcentrators for Pomegranate Juice

The designs of cryoconcentrators of block type BV-2 and BL-20 have been developed. The influence of design and operating parameters on the kinetics of freezing of pomegranate juice was investigated. A decrease in the operating temperature of the refrigeration unit contributes to a more intensive growth of the ice block. When the temperature of the coolant decreases by 1.2 times, the productivity of the BV-2 unit increases by 27 %, and of the BL-20 unit by 12 %. For BL-20, an increase in the initial concentration by 3 times leads to a decrease in productivity by 2.5...1.5 times. The influence of the temperature of the coolant and the initial concentration of the juice on the rate of concentration change has been determined. At low initial concentrations of solutions (10...15 %), a sharp increase in concentration is observed at the final stage of freezing. The dry matter content of the juice is increased by 16 % at high concentrations, only 4 %. The kinetics of the ice block separation process has been studied. At the first stage (duration 10...15 minutes), the concentration of effluents is 2...3 % higher than the concentration of the solution. On the second, increases by 6...10 %. In the third stage, there is a monotonous decrease in effluent concentration (2.5 % / hour). The results of experimental modeling are generalized. The obtained equation in similarity numbers allows calculating the mass transfer coefficients with an error of no more than 20 %. The developed designs of the BL-20 and BV-2 cryoconcentrators are semi-industrial units. With block cryoconcentration, a concentration of pomegranate juice of 47° Brix was achieved, which is higher than in traditional devices. The results obtained can be applied for further development and creation of industrial plants with optimal improved product parameters