scholarly journals Convective Thin-Layer Drying Characteristics of Sesame Seed

Author(s):  
O.U. Dairo ◽  
T.M.A. Olayanju

Fundamental Information on Drying and Re-Wetting Characteristics of Agricultural Seeds Is Required in the Design and Aeration Systems as Well as in the Prediction of Drying Rate Using Various Mathematical Models. Thin-Layer Drying Experiments Were Conducted Using Air-Ventilated Oven to Simulate the Artificial Drying at Various Moisture Contents of Sesame Seed (6.9 to 18.2 % W.b) at Three Drying Temperatures of 40, 50 and 60OC. Five Drying Models Were Evaluated for the Thin-Layer Data. the Page Equation Fitted the Data Best, where Selection of the Best Model Was Obtained by Comparing the Coefficient of Determination (R2), the Standard Error of Moisture Content (SEM) and Mean Relative Percent Error (e) between the Experimental and Estimated Values. the Drying Rate of Sesame Seed under Drying Conditions Increased with Increased Temperature of Drying( 40 to 60OC) and Initial Moisture Content of Seed( 6.9, 11.5 and 18.2 % W.b). the Parameters “K” of the Page Model Increased with Increase in Temperature, while, Parameter ”n” Decreased with Temperature Increase and Increased with Increase in Moisture Content of Seed. the Effective Diffusivity Was Found to Be 2.32 X 10-11 M2s-1.

Food Research ◽  
2021 ◽  
Vol 5 (5) ◽  
pp. 244-249
Author(s):  
N.V. Tai ◽  
M.N. Linh ◽  
N.M. Thuy

In Vietnam, banana peels have been discarded as waste which is a potential source of raw material for food and other bioprocessing industries. Drying the peel offers opportunities for value addition into novel products, thus reducing waste from the fruit processing operations. This study presented the mathematical models of the thin-layer drying behaviour of banana peels using three air temperatures (60oC, 70oC and 80oC). The effect of drying temperature on the reduction of moisture content and drying rate of the banana peel was evaluated. A total of eight commonly drying models were used for choosing the best fitness model for describing the oven drying process. The effective moisture diffusivity and activation energy were calculated using Fick’s diffusion equation. The obtained results showed that increasing drying temperature accelerate the drying process, as well as, increasing drying rate and effective diffusivity. The goodness of fit tests base on the criterion indicated that the Page model gave the best fit to experimental results. The effective diffusivity varied from 2.29×10-8 – 3.25×10-8 m 2 /s. Effective diffusivity was satisfactorily by an Arrhenius relationship with activation energy within the 60-80°C temperature range. The obtained activation energy was 16.98 kJ/mol with a high coefficient of determination (R2 = 0.903).


2018 ◽  
Vol 2 ◽  
pp. 53-58
Author(s):  
Arjun Ghimire ◽  
Nirajan Magar

Curry leaves (Murraya koenigii L.) are the sweet smelling leaves of small tree of Rutaceae family native to Southwest Asia. In this study, the effect of temperatures (50, 55 and 60°C) on the drying of curry leaves was investigated. The experimental data were fitted to six thin layer mathematical models (Newton, Page, Handerson and Pabis, logarithmic, two-term exponential and Midilli et al). The models were evaluated in terms of coefficient of determination (R2), chi square (χ2) and root mean square error (RMSE). The Midilli et al model was best fitted to the experimental data of all the models evaluated. The effective diffusivity was calculated using Fick's diffusion equation, and the value varied from 2.07×10-12 m2/s to 2.643×10-12 m2/s. The activation energy and the diffusivity constant were found to be 21.808 kJ/mol and 4.667×10-8 m2/s respectively.


2007 ◽  
Vol 13 (2) ◽  
pp. 91-97 ◽  
Author(s):  
J. Sun ◽  
X. Hu ◽  
G. Zhao ◽  
J. Wu ◽  
Z. Wang ◽  
...  

Thin-layer infrared drying characteristics of apple pomace, with and without hot air pre-drying, were studied with a laboratory scale infrared dryer. Moreover, ten commonly used mathematical models were used to fit experimental data. Logarithmic model and Page model were most adequate in describing thin-layer drying of fresh and pre-treated apple pomace respectively. The values of average effective diffusivity in drying the pre-treated apple pomace were about 1.3 times of that in the fresh apple pomace with the initial moisture content of 40% (wet basis).The values of activation energy of moisture diffusion were about 30 kJ/mol for the fresh and pre-treated apple pomace respectively. Infrared drying, combined with hot air pre-drying, can save 20% of drying time to remove the same amount of remained moisture as compared to the infrared drying alone. The above findings might be used for operation of drying apple pomace.


2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Akinjide A Akinola ◽  
Stanley N. Ezeorah

 This study aims to investigate the drying characteristics of cassava, yam, and potato slices using a laboratory scale batch Refractance Window™ (RW) dryer. The experimental dryer was constructed by modifying a laboratory water bath. The bath was covered with a transparent Polyethylene terephthalate (PET) plastic film held in-place with angled edges. The cassava, yam, and potato slices were dried on the Refractance WindowTM dryer, and the variation of the moisture content of the slices during the drying process was measured. The water temperature beneath the plastic film was maintained at 60oC. The dehydration data were fitted to thin-layer drying models. Regression analysis suggested that the Haghi and Ghanadzadeh model best describes the dehydration behaviour for the 3 mm thick slices for the cassava, yam, and potato tubers. The coefficient of determination (R2) values of 0.999, 0.998, and 0.998 for the cassava, yam, and potato slices respectively were reported in all the models studied. The drying curves, the drying rate curves, and the Krischer curves, from the experimental drying data, was plotted. Observations indicate that the cassava, yams, and potatoes slices dried to below 0.11 g water/g-solid moisture content in about 150 min. This study was performed to facilitate the understanding of the design, modelling, and operations of a continuously operating RW dryer. Keywords: Refractance Window Drying, Thin Layer Drying Models, Yams, Cassava, Potatoes.


Author(s):  
Joseph Oppong Akowuah ◽  
Ato Bart-Plange ◽  
Komla A. Dzisi

Performance of a tractor mounted solar-biomass hybrid dryer which utilise combined energy of solar and biomass was investigated. Drying behaviour of maize grains in the dryer was also investigated using 10 thin-layer mathematical models. The models were compared based on coefficient of determination (R<sup>2</sup>) and root mean square error (RMSE) values between experimental and predicted moisture ratios. Moisture content (MC) of grains in the dryer reduced from 19 ± 0.86% to 13 ± 0.4% (w.b.) in 5 h, compared to grains dried in open-sun which reached same MC in 15 hours. This resulted in average drying rate of 1.2 %·h<sup>–1</sup> compared to 0.4 %·h<sup>–1</sup> for grains dried in the open-sun leading to net savings in drying time of 67%. Overall mean temperature, 41.93 ± 2.7 °C in the dryer was 15.3 °C higher than the ambient temperature. Midilli Kucuk model was best to describe the thin-layer drying kinetics of maize in the dryer. It showed a good fit between the predicted and experimental data. The effective moisture diffusivity of grains dried in the dryer ranged between 1.45 × 10<sup>–11</sup> m<sup>2</sup>·s<sup>–1</sup> – 3.10 × 10<sup>–11</sup> m<sup>2</sup>·s<sup>–1</sup>. An activation energy of 96.83 kJ·mol<sup>–1</sup> was determined based on the Arrhenius-type equation.


Author(s):  
Egbe E. W. ◽  
Davies R. M.

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.


2013 ◽  
Vol 38 (2) ◽  
pp. 301-319 ◽  
Author(s):  
MA Hoque ◽  
BK Bala ◽  
MA Hossain ◽  
M Borhan Uddin

This paper presents the drying kinetics of ginger rhizome under blanched and nonblanched conditions using hybrid solar dryer and mechanical tray dryer at three temperature levels. The drying rate increases with the increase in drying air temperature and blanching also increases the drying rate. The drying rate depends on shape and size of the ginger rhizomes. The highest drying rate was found for sliced samples of ginger rhizome followed by splitted and whole root samples. Five thin layer drying models were fitted to the experimental data of blanched and sliced ginger rhizomes. The Page equation was found to be the best to predict the moisture content of sliced ginger rhizome in thin layer. The agreement between the predicted and experimental results was excellent. Colour of ginger rhizomes was slightly changed after drying. Lightness of ginger rhizomes decreased with an increase in drying temperature for all samples except sliced and blanched samples. For drying of ginger rhizome, it should be sliced and blanched and dried below 70°C for better quality dried products. Bangladesh J. Agril. Res. 38(2): 301-319, June 2013 DOI: http://dx.doi.org/10.3329/bjar.v38i2.15892


2000 ◽  
Vol 18 (7) ◽  
pp. 1465-1479 ◽  
Author(s):  
Murat Özdemir ◽  
Ferda G. Seyhan ◽  
A. Özdeş Bodurb ◽  
Y. Onur Devres

Author(s):  
Abdul Wasim Noori ◽  
Mohammad Jafar Royen ◽  
Juma Haydary

This paper aims to investigate the effect of climate conditions such as ambient temperature, humidity, pressure, sun radiation and pollution on sliced apples quality and drying time which are dried in an indirect forced cabinet solar drying (IFCSD) and open sun drying (OSD) systems. Both experiments were implemented at same place (Kabul, Afghanistan) and time. The IFCSD yield for saving time is 42.8 % which is more effective than drying in the OSD system. Simultaneously with the decreasing of sliced apple weight from 512.9 g down to 73.9 g, the water activity decreased from 0.955 down to 0.355 in the IFCSD system. For OSD system, the sample weight decreased from 512.6 g down to 78.4 g and its water activity from 0.955 down to 0.411. On the experiment day the average sun radiation was 571 w/m2 . The pressure drop between inlet and outlet of the dryer was 0.1 kPa. Different thin-layer mathematical models were investigated to identify the best model fitting the experimental data. The mathematical models’ performances were investigated by comparing the coefficient of determination (R 2 ), reduced chi-square (X2 ) and root mean square error (RMSE) coefficients. From all 11 applied thin-layer drying models the Page, Approximation diffusion, Verma et al and Midilli and Kacuk models are more fitted to our data.


2014 ◽  
Vol 69 (9) ◽  
pp. 1859-1866 ◽  
Author(s):  
Hui-Ling Wang ◽  
Zhao-Hui Yang ◽  
Jing Huang ◽  
Li-Ke Wang ◽  
Cheng-Liu Gou ◽  
...  

As dewatered sludge is highly viscous and sticky, the combination of foaming pretreatment and drying process seems to be an alternative method to improve the drying performance of dewatered sludge. In this study, CaO addition followed by mechanical whipping was employed for foaming the dewatered sludge. It was found that the foams were stable and the diameters of bubbles mainly ranged from 0.1 to 0.3 mm. The drying experiments were carried out in a drying oven in the convective mode. The results indicated that foamed sludge at 0.70 g/cm3 had the best drying performance at each level of temperature, which could save 35–45% drying time to reach 20% moisture content compared with the non-foamed sludge. The drying rate of foamed sludge at 0.70 g/cm3 was improved with the increasing of drying temperature. The impact of sample thickness on drying rate was not obvious when the sample thickness increased from 2 to 8 mm. Different mathematical models were used for the simulation of foamed sludge drying curves. The Wang and Singh model represented the drying characteristics better than other models with coefficient of determination values over 0.99.


Sign in / Sign up

Export Citation Format

Share Document