The dehydration parameters (temperature, thickness, and mass load) statistically significantly (p<0.05) affect the thin-layer convective dehydration of potato slices. The slices with thicknesses of 3, 5, and 8 mm were dehydrated as monolayers at different temperatures (30, 50, and 70 °C) and mass load (1.00, 0.63, and 0.38 kg m-2). The results showed that the shortest dehydration time (183 minutes), the smallest energy consumption (0.176 kWh), and the smallest emission of carbon dioxide (0.17 kg) had the dehydration model of potato slices with a 3 mm thickness, 0.38 kg m-2 mass load, dehydrated on the temperature of 70 °C. Dehydration of potato slices of 8 mm slice thickness dehydrated at 70 °C, with 0.38 kg m-2 mass load, showed the highest resistance to mass transfer (the maximum effective moisture diffusivity 2.3761 × 10-7 ± 4.45646 × 10-9 m2 s−1) and the minimum activation energy (27.02 kJ mol-1). Data obtained from these mathematical models could predict and optimize the thin layer dehydration of potato slices, with a dominant influence of temperature and potato slice thickness parameters as variables.

The effective moisture diffusivity (Deff), the energy of activation (Ea) and total energy input (Q) are appropriate parameters for modeling and energy efficiency estimation of the thin layer dehydration process of chokeberry under the different air temperature (50, 55, 60, 65 and 70 °C). Increasing the dehydration temperature will statistically significantly increased the Deff from 2.93×10-6 m2 s-1 (50 °C) to 7.77×10-6 m2 s-1 (70 °C), and decreased the Ei ,• from 2594.77 kJ to 2474.35 kJ, respectively. As the drying temperature was increased and consecutive drying time has been reduced (from 37 hours to 23 hours), energy input statistically significantly decreased. Mathematical models showed a good correlation between calculated and experimental values and allowed good prediction of dehydration parameters, enhancing energy efficiency. The Ea for the experimental model of thin layer chokeberry dehydration was 45.37 kJ mol-1.

No abstract

The effects of different dehydration temperature (35, 50 and 70 °C) and carrot slice thickness (3, 6, and 9 mm), at the constant (hot) air speed and mass load, on moisture ratio (MR) and drying ratio (DR) in thin layer convective drying process were investigated. The mathematical models Modified Page, Logarithmic, and Two-term models (for MR), and Gauss Modified model (for DR) were the most appropriate. Based on the obtained results for the R2 and RSME, the optimal parameters for thin layer drying carrot slices in laboratory dehydrator are dehydration temperature 70 °C, and carrot slice thickness of 3 mm, with the shortest dehydration time of 4.5 hours and the maximum DR of 106.7 g/h.

Problems of transforming heavy crude high-sulfur oil into low-sulfur fuels and oils become increasingly urgent for oil refineries. The main reason for that is depletion of low-sulfur oil-fields and following rise of heavy crude oil share in world's oil production. Desulfurization of oil and petroleum residues is performed by breaking down or extraction of sulfur and sulfur compounds with catalyst and chemical additives which leads to considerable rise in price of refinery. Desulfurization technology proposed in the following research involves simultaneous use of the acoustic and hydrodynamical cavitation for breaking down long molecular connections. Oil refinery was performed in the electromechanical vortex layer activator which intensified mechanoactivation processes by intensive movement of ferromagnetic elements in the external magnetic field.

The influence of thin layer convective dehydration parameters on drying kinetics parameters, chemical composition, and color parameters of carrot slices were investigated, and corresponding mathematical models were developed. In the carrot slices, convective dehydration process hot air temperature and the sample slice thickness were varied, while measured, calculated, and modeled responses were: time of dehydration, effective moisture diffusivity, the energy of activation, proteins and cellulose contents, lightness, redness, and yellowness. The obtained results showed that varied convective dehydration process parameters statistically significantly affected all investigated responses except activation energy. The most efficient drying model with the minimum thickness (3 mm) and the maximum drying temperature (70 ?C) had the shortest drying time (231 min). This model had the minimum resistance to mass transfer (the minimum effective moisture diffusivity, 2.04?10-08 - 7.12?10-08 [m2s-1]), and the average maximum energy of activation (31.31 kJmol-1). As far as the carrot slices' chemical composition and color parameters were concerned, the model with the maximum thickness (9 mm) and the minimum drying temperature (35 ?C) was the optimal one. This model had the longest dehydration time (934 min), the maximum resistance to the mass transfer (8.87?10-08 [m2s-1]), the minimum total protein content (5.26 %), and the darkest color (49.70). The highest protein content (7.91%) was found for the samples subjected to the highest drying temperatures and the lowest carrot slice thickness. In contrast, the process of convective dehydration had led to the lighter, reddish, and yellowish carrot slices. All developed mathematical models were statistically significant.

No abstract

No abstract