scholarly journals Kinetics, energy efficiency and mathematical modeling of thin layer solar drying of figs (Ficus carica L.)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lahcen Hssaini ◽  
Rachida Ouaabou ◽  
Hafida Hanine ◽  
Rachid Razouk ◽  
Ali Idlimam
Keyword(s):  
Energy Efficiency ◽  
Thin Layer ◽  
Air Flow ◽  
Moisture Diffusivity ◽  
Energy Utilization ◽  
Ficus Carica ◽  
Effective Moisture Diffusivity ◽  
Drying Time ◽  
Effective Moisture ◽  
Thin Layer Drying

AbstractFirst convectional thin layer drying of two fig (Ficus carica L.) varieties growing in Moroccan, using partially indirect convective dryer, was performed. The experimental design combined three air temperatures levels (60, 70 and 80 °C) and two air-flow rates (150 and 300 m3/h). Fig drying curve was defined as a third-order polynomial equation linking the sample moisture content to the effective moisture diffusivity. The average activation energy was ranged between 4699.41 and 7502.37 kJ/kg. It raised proportionally with the air flow velocity, and the same pattern were observed for effective moisture diffusivity regarding drying time and velocity. High levels of temperature (80 °C) and velocity (300 m3/h) lead to shorten drying time (200 min) and improve the slices physical quality. Among the nine tested models, Modified Handerson and Pabis exhibited the highest correlation coefficient value with the lowest chi-square for both varieties, and then give the best prediction performance. Energetic investigation of the dryer prototype showed that the total use of energy alongside with the specific energy utilization (13.12 and 44.55 MWh/kg) were inversely proportional to the velocity and drying temperature. Likewise, the energy efficiency was greater (3.98%) higher in drying conditions.

scholarly journals Optimization and Prediction of the Drying and Quality of Turnip Slices by Convective-Infrared Dryer under Various Pretreatments by RSM and ANFIS Methods

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 284
Author(s):  
Ebrahim Taghinezhad ◽  
Mohammad Kaveh ◽  
Antoni Szumny
Keyword(s):  
Energy Efficiency ◽  
Color Difference ◽  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Diffusivity Coefficient ◽  
Drying Process ◽  
Anfis Model ◽  
Drying Time ◽  
Effective Moisture ◽  
Response Variables

Drying can prolong the shelf life of a product by reducing microbial activities while facilitating its transportation and storage by decreasing the product weight and volume. The quality factors of the drying process are among the important issues in the drying of food and agricultural products. In this study, the effects of several independent variables such as the temperature of the drying air (50, 60, and 70 °C) and the thickness of the samples (2, 4, and 6 mm) were studied on the response variables including the quality indices (color difference and shrinkage) and drying factors (drying time, effective moisture diffusivity coefficient, specific energy consumption (SEC), energy efficiency and dryer efficiency) of the turnip slices dried by a hybrid convective-infrared (HCIR) dryer. Before drying, the samples were treated by three pretreatments: microwave (360 W for 2.5 min), ultrasonic (at 30 °C for 10 min) and blanching (at 90 °C for 2 min). The statistical analyses of the data and optimization of the drying process were achieved by the response surface method (RSM) and the response variables were predicted by the adaptive neuro-fuzzy inference system (ANFIS) model. The results indicated that an increase in the dryer temperature and a decline in the thickness of the sample can enhance the evaporation rate of the samples which will decrease the drying time (40–20 min), SEC (from 168.98 to 21.57 MJ/kg), color difference (from 50.59 to 15.38) and shrinkage (from 67.84% to 24.28%) while increasing the effective moisture diffusivity coefficient (from 1.007 × 10−9 to 8.11 × 10−9 m2/s), energy efficiency (from 0.89% to 15.23%) and dryer efficiency (from 2.11% to 21.2%). Compared to ultrasonic and blanching, microwave pretreatment increased the energy and drying efficiency; while the variations in the color and shrinkage were the lowest in the ultrasonic pretreatment. The optimal condition involved the temperature of 70 °C and sample thickness of 2 mm with the desirability above 0.89. The ANFIS model also managed to predict the response variables with R2 > 0.96.

Determination of Moisture Diffusivity and Activation Energy in Thin Layer Drying of Olive Pomace

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Smail Meziane ◽  
Naima Mesbahi
Keyword(s):  
Activation Energy ◽  
Thin Layer ◽  
Moisture Diffusivity ◽  
Olive Pomace ◽  
Air Velocity ◽  
Drying Time ◽  
Effective Moisture ◽  
Air Temperatures ◽  
Thin Layer Drying

Abstract The thin layer drying of olive pomace was experimentally studied in a laboratory convective dryer. Drying experiments were performed under five air temperatures of 60, 70, 80 and 90ºC, two air velocities of 1.0 and 1.8 m s-1 and three thickness of thin layer of 6, 9 and 12 mm. The results show that the drying time decreased with increased in drying temperature and air velocity but increased with the decreasing of thin layer thickness of olive pomace. Over the experimental range studied, the values of effective moisture diffusivity and activation energy ranged from 1.25 • 10-9 to 6.30 • 10-9 m2 s-1 and 26.30 to 37.63 kJ mol-1, respectively. The dependence of these parameters on thickness of thin layer, and temperature and velocity of drying air has been investigated.

Characteristics of sunflower seed drying and microwave energy consumption

2013 ◽  
Vol 27 (2) ◽  
pp. 127-132 ◽  
Author(s):  
H. Darvishi ◽  
M. Hadi Khoshtaghaza ◽  
G. Najafi ◽  
M. Zarein
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Specific Energy ◽  
Microwave Power ◽  
Specific Energy Consumption ◽  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Convective Drying ◽  
Drying Time ◽  
Effective Moisture

Abstract The effect of the microwave-convective drying technique on the moisture ratio, drying rate, drying time, effective moisture diffusivity, microwave specific energy consumption, and energy efficiency of sunflower seedswere investigated.Drying took place in the falling rate period. Increasing the microwave power caused a significant decrease in the drying time. The drying data were fitted to four thin-layer drying models. The performance of these models was compared using the coefficient of determination, reduced chi-square and root mean square error between the observed and predicted moisture ratios. The results showed that the Page model was found to satisfactorily describe themicrowave-convective drying curves of sunflower seeds. The effective moisture diffusivity values were estimated from Fick diffusion model and varied from 1.73 10-7 to 4.76 10-7m2s-1. Increasing the microwave power resulted in a considerable increase in drying efficiency and a significant decrease in microwave specific energy consumption. The highest energy efficiency and the lowestmicrowave specific energy consumption were obtained at the microwave power of 300 W.

scholarly journals Estimating the Drying Kinetics and Effective Moisture Diffusivity of Fresh Water Prawn (Macrobrachium rosenbergii)

2021 ◽  
pp. 40-48
Author(s):  
Egbe E. W. ◽  
Davies R. M.
Keyword(s):  
Thin Layer ◽  
Fresh Water ◽  
Initial Moisture Content ◽  
Macrobrachium Rosenbergii ◽  
Moisture Diffusivity ◽  
Drying Kinetics ◽  
Effective Moisture Diffusivity ◽  
Coefficient Of Determination ◽  
Effective Moisture ◽  
Thin Layer Drying

Fresh-water prawn (Macrobrachium rosenbergii) once harvested, tends to deteriorate rapidly because of the high systemic moisture it constituent which has lead to post-harvest losses, drying as a method of preservation widely used for high moisture bio-products reduces moisture probably to bone-dry level and thereby increased the shelf-life of the fresh-water prawn. Therefore, Estimating the Drying Kinetics and Effective Moisture Diffusivity of Fresh Water Prawn (Macrobrachium rosenbergii) was investigated using a laboratory convective oven dryer and was arranged in a thin layer. 50-100°C temperatures were applied, varying on multiple of 10°C. It was observed that the drying rate increased with increasing drying temperatures. Drying data obtained were fitted into four empirical thin-layer drying models, and the best model was investigated after undergoing statistical parameters (of coefficient of determination, R2; root mean square error, RMSE and reduced chi-square, χ2). The ANN and Henderson model was found to perform satisfactorily in describing the drying behaviour of the Fresh-water prawn samples at the chosen temperature levels. The initial moisture content of all the samples was 54% wb. The final effective moisture diffusivity of the samples during the drying experiments ranges from 1.26 x 10-7m2/s - 7.06 x 10-7m2/s, and the temperature related activation energy of diffusion was found to be 12.82-kJ/mol. Drying occurred mainly in the falling rate period, and the characterizing drying curves were exponential with increase in drying temperatures.

scholarly journals Influence of Drying Conditions on the Effective Moisture Diffusivity and Energy Requirements of Ginger Slices

2014 ◽  
Vol 3 (5) ◽  
pp. 103 ◽  
Author(s):  
Tinuade J. Afolabi ◽  
Toyosi Y. Tunde-Akintunde ◽  
Olusegun J. Oyelade
Keyword(s):  
Air Temperature ◽  
Energy Requirement ◽  
Ambient Air ◽  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Slice Thickness ◽  
Drying Time ◽  
Effective Moisture ◽  
Thin Layer Drying ◽  
Drying Conditions

<p>The thin layer drying behaviour of ginger slices in a laboratory dryer was examined. The slices of 5 mm, 10 mm and 15 mm thicknesses were dried using heated ambient air at temperatures from 40 to 70 ºC and air velocity of 1.5 m/s. The effects of drying air temperature and slice thickness on the drying characteristics, drying time and energy requirement of drying process was determined. The results have shown that an increase in the drying air temperature causes shorter drying times. Thinner slices also causes a shorter drying time. The effective moisture diffusivity values increased from 3.36814 × 10<sup>-10</sup> m<sup>2</sup>/s to 5.82524 × 10<sup>-9</sup> m<sup>2</sup>/s while the activation energy values for different slice thickness of ginger varied from 196.15 to 198.79 kJ/mol. The total needed energy varied from 735.3 to 868.5 kWh while the value of specific energy requirement varied from 3676.6 to 4342.4 kWh/kg respectively.</p>

scholarly journals Mathematical modelling of thin layer drying of pear

2016 ◽  
Vol 22 (2) ◽  
pp. 191-199 ◽  
Author(s):  
Monika Lutovska ◽  
Vangelce Mitrevski ◽  
Ivan Pavkov ◽  
Vladimir Mijakovski ◽  
Milivoj Radojcin
Keyword(s):  
Experimental Data ◽  
Thin Layer ◽  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Data Set ◽  
Effective Moisture ◽  
Air Temperatures ◽  
Thin Layer Drying ◽  
Drying Kinetic ◽  
Drying Conditions

In this study, a thin - layer drying of pear slices as a function of drying conditions were examined. The experimental data set of thin - layer drying kinetics at five drying air temperatures 30, 40, 50, 60 and 70?C, and three drying air velocities 1, 1.5 and 2 m s-1 were obtained on the experimental setup, designed to imitate industrial convective dryer. Five well known thin - layer drying models from scientific literature were used to approximate the experimental data in terms of moisture ratio. In order to find which model gives the best results, numerical experiments were made. For each model and data set, the statistical performance index, (?), and chi-squared, (?2), value were calculated and models were ranked afterwards. The performed statistical analysis shows that the model of Midilli gives the best statistical results. Because the effect of drying air temperature and drying air velocity on the empirical parameters was not included in the base Midilli model, in this study the generalized form of this model was developed. With this model, the drying kinetic data of pear slices can be approximated with high accuracy. The effective moisture diffusivity was determined by using Fick?s second laws. The obtained values of the effective moisture diffusivity, (Deff), during drying ranged between 6.49 x 10-9 and 3.29 x 10-8 m2 s-1, while the values of activation energy (E0) varied between 28.15 to 30.51 kJ mol-1.

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