Utilisation of the REA-method to a Convective Drying of Apple Rings at Ambient Temperature

2020 ◽  
Vol 16 (5-6) ◽  
Author(s):  
Sergey Spotar ◽  
Sayara Saliyeva ◽  
Alibek Kopbayev ◽  
Temirlan Shildebayev
Keyword(s):  
Mass Transfer ◽  
Ambient Temperature ◽  
Reaction Engineering ◽  
Convective Drying ◽  
Energy Curve ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Series Of Experiments ◽  
Reference Measurements ◽  
Normal Processing

AbstractThis study focuses on the convective drying of apple rings by air at ambient temperature. The lumped reaction engineering approach (REA) model has been employed to determine the rate of drying for apple rings under forced convection considered as a normal processing regime. The algorithm implies origination of the activation energy curve from accurate ‘reference’ measurements of the drying rate under natural convection conditions. Mass transfer coefficients for the apple ring samples required for the model implementation were obtained in a series of experiments under natural and forced conditions. These were compared to the values of mass transfer coefficients obtained from numerical simulation using COMSOL Multiphysics® software. The study extends the application of REA for the limiting simplest case of convective drying of thick samples under ambient temperature conditions.

Application of REA-method to a convective drying of apple rings at ambient temperature

2018 ◽  
Author(s):  
D. Bulegenov ◽  
Sayara Saliyeva ◽  
A. Sekerbayeva ◽  
Sergey Spotar
Keyword(s):  
Ambient Temperature ◽  
Ambient Air ◽  
Reaction Engineering ◽  
Convective Drying ◽  
Energy Curve ◽  
Drying Rate ◽  
Transfer Coefficients ◽  
Ambient Temperature Condition ◽  
Reference Measurements ◽  
Normal Processing

This study focuses on the convective drying of apple rings without any extra-heating of the processing ambient air. The lumped reaction engineering approach (REA) model has been employed to determine the rate of drying for the apple rings under forced convection considered as a normal processing regime. The algorithm implies determination the activation energy curve from the accurate ‘reference’ measurements of the drying rate under natural convection conditions. The required for the model implementation mass transfer coefficients for the apple ring samples under natural and forced conditions were obtained in the series of customized experiments. The study does extend the application of REA for the limiting simplest case of convective drying of thick samples under ambient temperature condition."

scholarly journals Description of Cumbeba (Tacinga inamoena) Waste Drying at Different Temperatures Using Diffusion Models

Foods ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1818
Author(s):  
João P. L. Ferreira ◽  
Wilton P. Silva ◽  
Alexandre J. M. Queiroz ◽  
Rossana M. F. Figueirêdo ◽  
Josivanda P. Gomes ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Effective Mass ◽  
Sample Surface ◽  
Fruit Production ◽  
Diffusion Models ◽  
Convective Drying ◽  
Convective Mass Transfer ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Drying Conditions

One approach to improve sustainable agro-industrial fruit production is to add value to the waste generated in pulp extraction. The processing of cumbeba (Tacinga inamoena) fruits generates a significant amount of waste, which is discarded without further application but can be a source of bioactive compounds, among other nutrients. Among the simplest and most inexpensive forms of processing, convective drying appears as the first option for the commercial utilization of fruit derivatives, but it is essential to understand the properties of mass transfer for the appropriate choice of drying conditions. In this study, cumbeba waste was dried at four temperatures (50, 60, 70 and 80 °C). Three diffusion models were fitted to the experimental data of the different drying conditions. Two boundary conditions on the sample surface were considered: equilibrium condition and convective condition. The simulations were performed simultaneously with the estimation of effective mass diffusivity coefficients (Def) and convective mass transfer coefficients (h). The validation of the models was verified by the agreement between the theoretical prediction (simulation) and the experimental results. The results showed that, for the best model, the effective mass diffusivities were 2.9285 × 10−9, 4.1695 × 10−9, 8.1395 × 10−9 and 1.2754 × 10−8 m2/s, while the convective mass transfer coefficients were 6.4362 × 10−7, 8.7273 × 10−7, 8.9445 × 10−7 and 1.0912 × 10−6 m/s. The coefficients of determination were greater than 0.995 and the chi-squares were lower than 2.2826 × 10−2 for all simulations of the experiments.

Pear Drying: Thermodynamics Studies and Coefficients of Convective Heat and Mass Transfer

2013 ◽  
Vol 9 (4) ◽  
pp. 365-374 ◽  
Author(s):  
Alexandre Navarro da Silva ◽  
Jane Sélia dos Reis Coimbra ◽  
Fernando Mendes Botelho ◽  
Moysés Naves de Moraes ◽  
Janaína Teles de Faria ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Convective Drying ◽  
Pyrus Pyrifolia ◽  
Drying Process ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Drying Behavior ◽  
Forced Air ◽  
Cylindrical Samples

AbstractThe objective of this work was to study the convective drying process used for cylindrical samples of two different pear varieties, one originating from Europe (Pyrus communis) and the other from Asia (Pyrus pyrifolia), submitted to two blanching treatments, as well as determine some coefficients referring to heat and mass transfer and thermodynamic parameters of the process, being: enthalpy (ΔH*), entropy (ΔS*) and Gibbs energy of activation (ΔG*). All samples were dried in a forced air oven at temperatures of (62, 76, 84 and 92)°C until reaching a constant mass. The heat and mass transfer coefficients referring to the constant and falling-rate drying periods were obtained by adjusting the experimental data to wet bulb temperature and liquid diffusion models, respectively. The heat and mass transfer coefficients varied linearly with temperature. Blanching altered the drying behavior of the two varieties in relation to the non-blanched samples, mainly at the elevated drying temperatures of 84°C and 92°C. ΔH* and ΔS* decreased while ΔG* increased with the elevation of drying temperature; therefore, it was possible to verify that variation in the diffusion process in pears during drying is dependent on energetic contributions of the environment.

Henry's constants and mass transfer coefficients of halogenated organic pollutants in an air stripping packed column

1998 ◽  
Vol 38 (6) ◽  
pp. 287-294 ◽  
Author(s):  
Pen-C. Chiang ◽  
Chung-H. Hung ◽  
J. C. Mar ◽  
E. E. Chang
Keyword(s):  
Mass Transfer ◽  
Methylene Chloride ◽  
Packed Column ◽  
Transfer Coefficients ◽  
Chlorinated Organic Compounds ◽  
Air Stripping ◽  
Mass Transfer Coefficients ◽  
Equilibrium Partition ◽  
Henry's Constants ◽  
Chlorinated Organic

Both Henry's constants and volumetric mass transfer coefficients (KLa) of eight priority chlorinated organic compounds including 1,1-dichloroethene, methylene chloride, chloroform, carbon tetrachloride, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene, and 1,4-dichlorobenzene in an air stripping packed column were investigated in this study. The liquid and gas phase EPICS (Equilibrium Partition in Closed System) and direct calculating methods were applied to determine the Henry's constants of VOCs. The interference of co-solute on Henry's constants was also investigated. Experimental results indicated that decrease in Henry's constants of VOCs was observed in the presence of humic acid but no apparent effect on Henry's constants was detected when there was NaCl and surfactant in solution. Four different configurations of packing media including Intalox Saddle, Super Intalox Saddle, Telleret, and Hedgehog made of polypropylene were respectively packed in the air stripping tower and investigated in the study. The dependence of hydraulic loading, air-water ratio, and configurations of packing media on mass transfer coefficients of VOCs was discussed.

Transport of chlorinated hydrocarbons between sewage and sewer atmosphere

1996 ◽  
Vol 34 (3-4) ◽  
pp. 557-564 ◽  
Author(s):  
Bettina S. Haas ◽  
Reimer Herrmann
Keyword(s):  
Mass Transfer ◽  
Aromatic Compounds ◽  
Chlorinated Hydrocarbons ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Sewerage System ◽  
Mass Fluxes ◽  
Single Compound

Sewage containing volatile contaminants is a potential VOC-source in cities. Thus we tried to evaluate volatilization out of the sewerage system by measurements of contaminants in sewer gas and sewage. Our results from a medium sized town with little industry showed that sewer gas is mainly contaminated with alkanes, small aromatic compounds and chlorinated hydrocarbons. For three chlorinated hydrocarbons (chloroform, trichloroethene, tetrachloroethene) we determined mass transfer coefficients out of sewage and used these data to estimate mass fluxes from sewage and emissions out of the sewerage system for two sewer stretches. Considerable emission of chlorinated hydrocarbons from sewage, i.e. fluxes of some 10 to 100 g per m2·d, occurred only when the contaminant input via sewage was between some g and mg per litre for a single compound. For concentrations that were about 3 orders of magnitude less, emissions were negligible.

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