The thin-layer drying characteristics of sewage sludge by the appropriate foaming pretreatment

2014 ◽  
Vol 69 (9) ◽  
pp. 1859-1866 ◽  
Author(s):  
Hui-Ling Wang ◽  
Zhao-Hui Yang ◽  
Jing Huang ◽  
Li-Ke Wang ◽  
Cheng-Liu Gou ◽  
...  
Keyword(s):  
Sample Thickness ◽  
Coefficient Of Determination ◽  
Drying Rate ◽  
Drying Time ◽  
Drying Characteristics ◽  
Thin Layer Drying ◽  
Dewatered Sludge ◽  
Drying Curves ◽  
Sludge Drying ◽  
The Impact

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.

scholarly journals Modelling the Drying Characteristics and Kinetics of Hot Air-Drying of Unblanched Whole Red Pepper and Blanched Bitter Leaf Slices

2017 ◽  
Vol 5 (1) ◽  
pp. 24
Author(s):  
Samuel Enahoro Agarry
Keyword(s):  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Red Pepper ◽  
Coefficient Of Determination ◽  
Drying Time ◽  
Drying Characteristics ◽  
Hot Air ◽  
Effective Moisture ◽  
Drying Curves ◽  
Kinetics Of

The objective of this study was to investigate the drying characteristics and kinetics of red pepper and bitter leaf under the influence of different drying temperatures. The drying experiments were carried out at dry bulb temperature of 35, 45, 55 and 75oC, respectively in an oven dryer. The results showed that as drying temperature increased, drying rate also increased and the drying time decreased. It was observed that un-sliced red pepper and sliced bitter leaf would dry within 2.5-12 h and 1.67-7 h, respectively at temperature ranging from 75 to 35oC. The drying of red pepper and bitter leaf was both in the constant and falling rate period. Four semi-empirical mathematical drying models (Newton, Page, Henderson and Pabis, and Logarithmic models) were fitted to the experimental drying curves. The models were compared using the coefficient of determination (R^2) and the root mean square error (RMSE). The Page model has shown a better fit to the experimental drying data of red pepper and bitter leaf, respectively as relatively compared to other tested models. Moisture transport during drying was described by the application of Fick’s diffusion model and the effective moisture diffusivity was estimated. The value ranges from 15.69 to 84.79 × 10-9 m2/s and 0.294 to 1.263 × 10-9 m2/s for red pepper and bitter leaf, respectively. The Arrhenius-type relationship describes the temperature dependence of effective moisture diffusivity and was determined to be 37.11 kJ/mol and 32.86 kJ/mol for red pepper and bitter leaf, respectively. A correlation between the drying time and the heat transfer area was also developed.

scholarly journals Thin layer mathematical modelling of white maize in a mobile solar-biomass hybrid dryer

2021 ◽  
Author(s):  
Joseph Oppong Akowuah ◽  
Ato Bart-Plange ◽  
Komla A. Dzisi
Keyword(s):  
Thin Layer ◽  
Type Equation ◽  
Moisture Diffusivity ◽  
Coefficient Of Determination ◽  
Drying Rate ◽  
Mean Square ◽  
Drying Time ◽  
Thin Layer Drying ◽  
Drying Behaviour ◽  
Kinetics Of

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.

scholarly journals Solar Drying Kinetics of Cass Ava Slices in a Mixed Flow Dryer

2015 ◽  
Vol 18 (4) ◽  
pp. 102-107 ◽  
Author(s):  
Olawale Usman Dairo ◽  
Adewole Ayobami Aderinlewo ◽  
Olayemi Johnson Adeosun ◽  
Ibukun Adekola Ola ◽  
Tolulope Salaudeen
Keyword(s):  
Diffusion Mechanism ◽  
Coefficient Of Determination ◽  
Drying Time ◽  
Drying Characteristics ◽  
Solar Dryer ◽  
Thin Layer Drying ◽  
Chamber Temperature ◽  
Drying Models ◽  
Kinetics Of ◽  
Drying Curve

Abstract Drying characteristics of cassava slices was investigated in a mixed mode natural convection solar dryer to obtain a suitable mathematical model describing the drying. The average drying chamber temperature was between 34 ±2 °C and 50 ±1.8 °C, while 10 commonly used thin layer drying models were used for drying curve modelling. Coefficient of determination (R2) and root mean square error (RMSE) were used to determine the models performances. The drying curve of cassava slices showed a reduction of moisture content with increased drying time in the solar dryer, and the variation of moisture ratio exponentially decreased with increased drying time. The Midilli and Logarithmic models showed better fit to the experimental drying data of cassava slices. As compared with other models tested, there were no significant differences (p >0.05) in the R2 values obtained for the Midilli and Logarithmic models; hence, the Logarithmic model was preferable because of the lower RMSE. The diffusion mechanism could be used to describe the drying of cassava slices that was found to be in the falling rate period. A diffusion coefficient (Deff) of 1.22 × 10-8 m2 s-1 was obtained, which was within the established standard for food products.

Drying characteristics and quality evaluation of dehydrated catfish (Clarias gariepinus)

2017 ◽  
Vol 47 (6) ◽  
pp. 765-779 ◽  
Author(s):  
Dupe Temilade Otolowo ◽  
Abiodun Adekunle Olapade ◽  
Samouel Olugbenga Oladele ◽  
Felix Egbuna
Keyword(s):  
Body Mass ◽  
Goodness Of Fit ◽  
Clarias Gariepinus ◽  
Processing Parameters ◽  
Commercial Application ◽  
Drying Rate ◽  
Drying Time ◽  
Drying Characteristics ◽  
Content Type ◽  
Thin Layer Drying

Purpose Fresh catfish (Clarias gariepinus) is highly perishable. This paper aims to investigate the drying characteristics and quality of body-mass dehydrated catfish to determine the effective dehydration parameters for preservation. Design/methodology/approach Brine concentration (3-9 per cent), brining time (30-90 min) and drying temperature (90-130°C) interacted using the response surface methodology. Preliminary experiments were conducted to select treatments. Moisture content and ratio and drying rate were determined and fitted into five thin-layer drying models; the goodness of fit was evaluated by average grade ranking of the regression parameters. Proximate compositions and microbial load of dehydrated catfish were determined using standard methods. Findings Treatments with 110°C gave initial higher drying rate (0.034-0.043 kg H2O/kg solid/h) and shorter drying time (20-21 h). Drying occurred at two falling rate periods. Midilli model ranked first in fitting the drying data. It explained up to 99.6-99.7 per cent of the total variations in the independent variables with low values of error terms; RMSE was 0.02131-0.01794 and χ2 was 0.00037-0.00043, indicating good predictive quality. Processing parameters positively and significantly (p < 0.05) influenced the proximate compositions of dehydrated catfish. Treatment: 6 per cent brine, 90 min and 110°C presented the most effective dehydration parameters for quality preservation of body-mass catfish. Practical implications The dehydration technique used in this study could enhance nutritive quality and storage stability of body-mass dehydrated catfish that could serve as a useful and convenient tool for commercial application. Social implications Hygienically processed dehydrated catfish of good quality could be used as a source of nutrients to ameliorate malnutrition and reduce post-harvest losses of catfish. Originality/value The effective processing parameters established is an important step to harness the high nutrients and economic values embedded in catfish.

Neural Network Approaches for Prediction of Pistachio Drying Kinetics

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Hamid Tavakolipour ◽  
Mohsen Mokhtarian
Keyword(s):  
Neural Network ◽  
Activation Function ◽  
Moisture Ratio ◽  
Coefficient Of Determination ◽  
Ann Model ◽  
Validation Data ◽  
Drying Time ◽  
Drying Characteristics ◽  
Thin Layer Drying ◽  
On Line

Abstract Thin-layer drying characteristics of whole pistachio were investigated by using a hot air convective dryer at a constant airflow velocity of 2 m.s-1 and air temperature in the range of 40-70°C. The experimental drying data were fitted to the eight well-known drying models i.e. the Newton, Page, Modified Page, Henderson and Pabis, Logarithmic, Diffusion, Thomson and New models. A predictive model using artificial neural network was proposed in order to obtain on-line predictions of moisture kinetics during drying of pistachio nut. For monitoring the drying process of pistachio, different activation function of neural networks such as tangent hyperbolic (tanh) and logarithmic sigmoid (logsig) were utilized. Drying time and air drying temperature were considered as network input and moisture ratio was as network output. The result indicated that tanh activation function gave better results than logsig activation function for monitoring the moisture ratio. Generally, perceptron neural network with logsig activation function as a goodness activation function was able to predict moisture ratio with 7 neuron in first and second hidden layer with R2 value equal 0.994. Investigation of validation data demonstrated that the predicted and experimental dying data were in good agreement. Comparing the R2 (coefficient of determination) and MAE using the developed ANN model it was concluded that the neural network could be used for on-line state estimation of drying characteristics and control of drying processes.

scholarly journals Modelling the Thin-Layer Drying Kinetics of Untreated and Blanch-Osmotic Pre-treated Tomato Slices

2016 ◽  
Vol 4 (10) ◽  
pp. 850 ◽  
Author(s):  
Samuel Enahoro Agarry
Keyword(s):  
Linear Regression Analysis ◽  
Drying Kinetics ◽  
Coefficient Of Determination ◽  
Drying Rate ◽  
Drying Time ◽  
Drying Temperature ◽  
Hot Air ◽  
Thin Layer Drying ◽  
Pre Treatment ◽  
Air Dryer

The objective of this study was to investigate the effect of pre-treatment and drying temperature on the drying kinetics and nutritional quality of tomato (Lycopersicon esculantum L.) under hot air drying. Tomato samples were blanched at 80oC and osmotically dehydrated using 20% w/w sodium chloride solutions at 30oC for 20 min. The blanch-osmotic pre-treated and untreated tomato slices were dried at temperature of 40, 50, 60, 70 and 80oC, respectively in a hot air-dryer. The results showed that blanch-osmotic pre-treatment offered a higher drying rate and lower or faster drying time than untreated condition. The tomato drying regime was characteristically in the constant and falling rate period. The tomato drying rate curve showed characteristics of porous hygroscopic solids. The optimum drying temperature for tomato was found to be 60oC. Four semi-empirical drying models of Newton, Page, Henderson and Pabis, and Logarithmic were fitted to the drying data using non-linear regression analysis. The most appropriate model was selected using the coefficient of determination (R2) and root mean square error (RMSE). The Page model has shown a better fit to the drying kinetics data of tomato in comparison with other tested models. Transport of moisture during drying was described by Fick’s diffusion model application and the effective moisture diffusivity (Deff) thus estimated. The Deff at 60oC was 4.43 × 10-11m2/s and 6.33 × 10-11m2/s for blanch-osmotic pre-treated and untreated tomato slices, respectively.

scholarly journals DRYING CHARACTERISTICS, MINERAL CONTENT, TEXTURE AND SENSORIAL PROPERTIES OF PUMPKIN FRUIT LEATHER

2021 ◽  
Vol 51 (3) ◽  
pp. 193-201
Author(s):  
Azime Özkan Karabacak ◽  
Senem Suna ◽  
Saliha Dorak ◽  
Ömer Utku Çopur
Keyword(s):  
Mineral Content ◽  
Moisture Diffusivity ◽  
Drying Rate ◽  
Textural Features ◽  
Drying Time ◽  
Drying Characteristics ◽  
Hot Air ◽  
Thin Layer Drying ◽  
Drying Models ◽  
Thin Layer Drying Models

The objective of this study was to investigate the influences of hot air (HAD: 50, 60, 70°C), vacuum (VD: 50, 60, 70°C at 300 mbar) and microwave methods (MWD: 90, 180W) on drying characteristics, effective moisture diffusivity (Deff), mineral content, texture, and sensorial properties of pumpkin pestils. MWD led to the highest drying rate and the lowest drying time in all methods. Page and Modified Page were ideally fitted to experimental results among seven thin layer drying models. Mineral content (Ca, K, Na, P, Mg, Fe, Zn, Cu, Mn) of the pestils showed higher values than non-dried (paste) mixture. Significant differences were determined between textural features of the pestils (p < 0.05). Furthermore, products dried with HAD and VD were preferred rather than MWD in terms of sensorial properties.

Thin Layer Drying Characteristics of Eriste: A Dried Cereal Product of Turkey

2008 ◽  
Vol 4 (2) ◽  
Author(s):  
Ayhan Duran ◽  
Ali Adnan Hayaloglu ◽  
Ihsan Karabulut
Keyword(s):  
Thin Layer ◽  
Air Temperature ◽  
Effective Diffusivity ◽  
Sample Thickness ◽  
Suitable Model ◽  
Sample Weight ◽  
Drying Characteristics ◽  
Thin Layer Drying ◽  
Cereal Product ◽  
Drying Curves

Effect of air temperature (50, 60 and 70 °C) and sample thickness (1.0, 1.4 and 1.8 mm) on the thin-layer drying characteristics of eriste was studied by using a tray dryer. The data of sample weight, dry and wet-bulb temperatures were recorded continuously during each experiment and drying curves were obtained. The drying curves were then fitted to five mathematical models available in the literature to estimate a suitable model for drying of eriste. Verma et al. model gave better predictions than other models and satisfactorily described the thin layer characteristics of eriste. The effective diffusivity varied from 1.8 x exp-10 to 1.5 x exp-9 m2 s-1 over the temperature range.

scholarly journals Drying Behavior and Kinetics of Drying Process of Plant-Based Enteric Hard Capsules

Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 335
Author(s):  
Chuqi He ◽  
Haodong Wang ◽  
Yucheng Yang ◽  
Yayan Huang ◽  
Xueqin Zhang ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Moisture Transfer ◽  
Chemical Properties ◽  
Moisture Diffusivity ◽  
Coefficient Of Determination ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Time ◽  
Thin Layer Drying ◽  
Air Dryer

The drying process is a significant step in the manufacturing process of enteric hard capsules, which affects the physical and chemical properties of the capsules. Thus, the drying characteristics of plant-based enteric hard capsules were investigated at a constant air velocity of 2 m/s in a bench scale hot-air dryer under a temperature range of 25 to 45 °C and relative humidity of 40 to 80%. Results indicate that the drying process of the capsules mainly occur in a falling-rate period, implying that moisture transfer in the capsules is governed by internal moisture diffusion rate. High temperature and low relative humidity reduce drying time but increase the drying rate of the capsules. Investigation results of the mechanical properties and storage stability of the capsules, however, reveal that a fast drying rate leads to plant-based enteric hard capsules of low quality. Scanning electron microscopy further demonstrates that more layered cracks appear in capsules produced under a faster drying rate. The Page model yielded the best fit for describing thin-layer drying of the capsules based on the coefficient of determination and reduced chi-square. Moreover, it was established that the effective moisture diffusivity of the capsules increases with an increase in drying temperature or reduction in relative humidity.

scholarly journals Drying Modelling, Moisture Diffusivity and Sensory quality of Thin Layer dried Beef

2018 ◽  
Vol 6 (2) ◽  
pp. 552-565 ◽  
Author(s):  
Eunice Akello Mewa ◽  
Michael Wandayi Okoth ◽  
Catherine Nkirote Kunyanga ◽  
Musa Njue Rugiri
Keyword(s):  
Thin Layer ◽  
Sensory Quality ◽  
Moisture Diffusivity ◽  
Drying Kinetics ◽  
Effect Of Temperature ◽  
Slice Thickness ◽  
Drying Time ◽  
Drying Characteristics ◽  
Thin Layer Drying

The objective of the present study was to determine the drying kinetics, moisture diffusivity and sensory quality of convective air dried beef. The effect of temperature of drying (30-60°C) and thickness of samples (2.5-10 mm) on the convective thin-layer drying kinetics of beefdried in a cabinet dryer was evaluated. Five semi-theoretical models were fit to the drying experimentaldata with the aim of predicting drying characteristics of beef and fitting quality of models determined using the standard error of estimate (SEE)and coefficient of determination (R2). Determination ofeffective moisture diffusivity (Deff) from the experimental drying datawas done and sensory quality of the optimized dried cooked and uncookedbeef samplesevaluated. Drying time and rate of drying increased with an increasing temperature but decreased with increased slice thickness. However, there was overlapping of drying curves at 40-50°C. Among the selected models, Page model gave the best prediction of beef drying characteristics. Effective moisture diffusivity (Deff) ranged between 4.2337 x 10-11 and 5.5899 x 10-10 m2/s, increasing with an increase in air temperature and beef slice thickness.Of all the sensory parameters evaluated, texture was the only attribute that gave significantly different (P > 0.05) scores between the cooked and uncooked dried beef samples.

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