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

Development of Wave Technologies to Intensify Heat and Mass Transfer Processes

The study has proved that in order to improve the heat technologies of food production, innovative principles of energy supply are needed. The hypotheses of using wave technologies for targeted delivery of energy to elements of food raw materials are proposed. Classification of the mechanisms of heat and mass transfer intensification in food processing technologies is given. Thermophysical models of the vibrational and barodiffusion mechanisms are presented. The possibilities of a combined action of these two mechanisms are determined. It is shown that vibrational and electromagnetic fields can significantly intensify the processes of heat and mass transfer. Mechanisms, effects and mathematical models of barodiffusion and the action of vibrational fields are justified.The method of “dimensional analysis” has determined the numbers of wave similarity: modified numbers of Reynolds, Péclet, and Stanton. New numbers of similarity are proposed: the number of energy action and the dimensionless complex that takes into account the ratio of inertial forces caused by vibration and movement of the conveyor belt. On the basis of these numbers, similarities are generalized in the criterial form of a database of experimental data on extraction and drying. The methodological novelty in the processing of these experiments is the use of an effective mass transfer coefficient that takes into account the total effect of diffusion and inertial flows of liquid from the solid phase.The experiments were carried out to dry sunflower seeds in a vibration dryer. The results of drying wheat seeds and peas on the belt with electromagnetic energy sources are shown in the form of dependency graphs and mathematical models based on the database of the experimental data. The drying speed achieved was 0.4 %/min on the vibrating dryer; on the IR belt dryer, this parameter was 0.75 %/min when drying peas and 1.75 %/min when drying sludge and seeds of sunflower.The results of the complex experimental research on coffee extraction in a microwave extractor are presented in the paper. The evaluation of the completeness of extraction of extractive substances under the action of the microwave field showed the results, on average, 15 % higher than by the standard thermal method. The prospects of the combined action of the electromagnetic and vibrational fields are shown on the basis of the results for optimizing the microwave extractor

Experimental Studies of the Kinetics of Infrared Drying of Spent Coffee Grounds

The object of research is drying of spent coffee grounds. In modern production, the issues of rational use of energy in all processes of food technology, including drying, are urgently raised. In many food technologies, 2–3 times more energy is used than is physically necessary for the process. This determines the energy intensity of production and the quality of products. Drying processes are among the most energy-intensive, and in many cases the proportion of energy in the cost of production is up to 30 %. When drying of spent coffee grounds, convective dryers are mainly used, the energy consumption of which is 5 MJ/kg of removed moisture and above. Convective drying uses 40 % of the supplied energy to evaporate moisture. Also, a significant drawback of convective dryers is the discharge of waste coolant into the atmosphere, which has a heat content of only 10–15 % less than the hot air supplied to the drying chamber. The paper proposes the use of infrared radiation for drying of spent coffee grounds in periodic and continuous units. This will allow in the future to reduce specific energy consumption. During the study, the influence of the energy supply intensity, temperature, air flow rate, product layer thickness and specific load on the kinetics of periodic infrared drying of spent coffee grounds is determined. The influence of the energy supply intensity, specific load, tape speed, and the number of infrared modules on the kinetics of continuous infrared drying of spent coffee grounds is determined. The results are compared with convective drying in terms of specific energy consumption. A feature of the use of infrared radiation is its high efficiency and high rate of moisture removal from the surface layers of spent coffee grounds, and as a result, an increase in the productivity of the drying method and a decrease in specific energy consumption. The specific energy consumption obtained during operation of infrared drying of spent coffee grounds is 3.2 MJ/kg. This is below existing convection dryers

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

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 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