scholarly journals Study of the drying kinetics of the malt bagasse in a pneumatic transporter

Author(s):  
Bruna Costa ◽  
Carolina Coelho ◽  
Cássia Souza ◽  
Gabriela Duarte ◽  
Maria Pinto ◽  
...  

Malt bagasse is a by-product of the brewing industry that has high moisture making it very unstable and susceptible to fast microbial deterioration. This work evaluated drying kinetic models of malt bagasse during pneumatic transport with air flow at 30, 45 and 60?C and layout of 4.5 and 7.0 m. The results showed that the decrease of moisture from malt bagasse was favored at higher air temperature due to the higher diffusion coefficient. In the ranges measured, the values of the effective moisture diffusivity and heat transfer coefficient were obtained between 2.05?10?10 to 12.74?10?10 m2/s and 175 to 363 W/m2K, respectively. Average energy for liquid diffusion in the malt bagasse drying process was 44.30 kJ/mol. Pneumatic transport with air flow at 60?C and layout of 7.0 m reached rapidly the final moisture of 12% (w.b), which it may reduce transport costs and allow long periods of stable storage for malt bagasse. The statistical tests results showed that the experimental datas presented excellent fit using the Modified Henderson-Pabis model, in the temperature range for both layouts.

2021 ◽  
Vol 2120 (1) ◽  
pp. 012036
Author(s):  
A Ali ◽  
B L Chua ◽  
Y H Chow

Abstract Continuous microwave is a heavily studied drying method known for its effectiveness and efficiency, however, it leads to overheating in most cases. The primary objective of the present research is conducting and evaluating a comparative study of continuous and periodic microwave drying on rosemary for various power levels (6, 9 and 12 W/g) and different pulse ratios to overcome the overheating challenge. The evaluation and assessment were based on drying and temperature kinetics. Drying kinetic study revealed that periodic and continuous microwave drying at 12 W/g had the least drying duration of 12.5 and 11 mins, respectively. Likewise, both processes had the highest drying rates of 0.364 and 0.461 kg H2O/ kg dry basis min. The temperature kinetic study showed that the periodic microwave drying (71.4°C) resulted in a lower maximum sample temperature than continuous microwave drying (79.2°C). The periodic microwave drying with higher pulse ratios had a more even heating throughout the drying process than lower pulse ratios. Thereby, periodic microwave drying at 12 W/g and the highest pulse ratio was deemed to be the most suitable drying process for rosemary. The four thin layer models, namely Page, Modified Page, Midilli & Kucuk and Modified Midilli & others, were the most suitable to describe the drying kinetics of rosemary.


2021 ◽  
Vol 13 (16) ◽  
pp. 9204
Author(s):  
Juan Manuel Castagnini ◽  
Silvia Tappi ◽  
Urszula Tylewicz ◽  
Santina Romani ◽  
Pietro Rocculi ◽  
...  

Novel products that carry concrete and relevant health benefits, with texture and flavor not substantially different from already available products, are generally well accepted by consumers. Vacuum impregnation is a non-thermal technology that allows the enrichment of fruit with different ingredients in solution. The characteristic of the resulting product is a combination of both the solid matrix and the impregnation solution. This work aimed at: (i) evaluating the effect of trehalose on anthocyanin retention after drying of apple snacks vacuum impregnated with blueberry juice; (ii) modelling the air-drying kinetic, proposing an image analysis approach to monitor the drying process. Four mathematical models successfully fitted the drying experimental data, obtainingequations that could be used in the implementation of this process at industrial scale. The drying kinetics of samples impregnated with blueberry juice and trehalose were faster when compared to the control sample. Samples impregnated with blueberry juice and 100 g/kg of trehalose retained nearly four times more anthocyanin after drying when compared to the control.


Author(s):  
Narjes Malekjani ◽  
Zahra Emam-Djomeh ◽  
Seyed Hassan Hashemabadi ◽  
Gholam Reza Askari

AbstractThe effects of microwave-convective drying as an efficient drying method, on drying kinetics of hazelnuts were studied. Drying experiments were conducted at three temperature (40, 50 and 60°C) and microwave power (0, 450 and 900 W) levels. The moisture ratio and the temperature of the hazelnuts were recorded during the drying. The results showed that microwave power had a more dominant effect than drying air temperature. Mathematical modeling was performed in order to predict the moisture changes during drying process. It was concluded that two term and Midilli et al. models were the best models to predict the drying kinetics of hazelnut in different conditions. The effective moisture diffusivities varied from 3.80327×10‒8to 1.71233×10‒6m2/s and had an increasing polynomial relationship with temperature and microwave power. The activation energy was also between 15.61675 and 41.0053 kJ/mol with a second-order relationship with microwave power.


2014 ◽  
Vol 10 (4) ◽  
pp. 839-848 ◽  
Author(s):  
Mehmet Başlar ◽  
Salih Karasu ◽  
Mahmut Kiliçli ◽  
Ahmet Abdullah Us ◽  
Osman Sağdiç

Abstract In this study, the drying kinetics of pomegranate arils, the degradation kinetics of some bioactive compounds, and changes in color values during the drying process were investigated. The drying process was performed by a forced air circulating oven at 55, 65, and 75°C. Drying times were calculated to be 1,020, 520, and 330 min, respectively. Effective moisture diffusivity values ranged from 5.39×10−11 to 1.70×10−10 m2 s−1 and increased with increases in temperature. Six different thin-layer drying models were applied to evaluate the goodness of the model. The degradation rate of bioactive compounds increased at higher temperatures; however, remaining amounts of phenolic, anthocyanin, and flavonoid compounds after drying were higher in samples dried at 75°C. The highest antioxidant capacity value was observed in the pomegranate arils dried at 75°C. While the L* values of pomegranate arils decreased after the drying process, the a* values increased.


2022 ◽  
Vol 52 (1) ◽  
pp. 43-48
Author(s):  
Ibrahim Doymaz

The effect of different infrared (IR) powers on drying of orange slices was investigated in infrared dryer. The orange slices dried at 62, 74 and 88 W infrared powers and constant slice thickness of 6 mm. Results showed that drying, colour and rehydration characteristics of orange slices were greatly influenced by infrared power. The drying data were fitted with five mathematical models available in the literature. Based on the statistical tests applied to make an assessment, the model of Midilli and Kucuk was found to satisfactorily explain drying kinetics of orange slices for all drying conditions. The Fick’s diffusion model was used to calculate the effective moisture diffusivity (Deff) of orange slices. The value of Deff varied from 1.59×10-10 to 2.49×10-10 m2/s. It was found that the effective moisture diffusivities increased with increasing IR power. Activation energy was estimated by a modified Arrhenius type equation as 2.11 kW/kg. As the infrared power increased, the rehydration ratio was found to be reduced. Furthermore, with increase of infrared power, the values of a and DE increased, whereas the values of L, b and C decreased.


2012 ◽  
Vol 326-328 ◽  
pp. 662-667 ◽  
Author(s):  
E. Barreira ◽  
João M.P.Q. Delgado ◽  
N.M.M. Ramos ◽  
V.P. de Freitas

Moisture is one of the most deteriorating factors of buildings. The moisture content depends on hygroscopic equilibrium between buildings materials and environment, which is determined by the drying and wetting rate of masonry. So, the moisture content is not only determined by the water that is absorbed by the material, but also by the amount of water that is evaporated under favourable conditions, which is described by the drying process. In this work we analyse the drying kinetics of External Thermal Insulation Composite Systems (ETICS) using a first-order and a second-order drying kinetic models to describe mass transfer phenomenon. The results show that the second-order kinetic models described well the drying process studied. The application of kinetics models to the experimental results was explored and several parameters were retrieved. A proposal for the use of these parameters is presented and its practical use is discussed.


Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 482
Author(s):  
Fatiha Berroug ◽  
Yassir Bellaziz ◽  
Naaila Ouazzani ◽  
Fatima Ait Nouh ◽  
Abdessamad Hejjaj ◽  
...  

Morocco is the leading producer of phosphate and its derivatives in the world with a total production of 35 Mt. However, the extraction and the valorization of this mine generate huge quantities of phosphate washing waste clay (PHWWC) that constitute a main environmental and economic concern. To facilitate this waste clay storage and handling, it is necessary to decrease its moisture content that represents 80% of PHWWC. The present paper is devoted to studying the conductive drying of PHWWC. Drying experiments were conducted in a laboratory pilot. Afterwards, the experiment results were implemented in a one-dimensional numerical model of heat and mass transfer in a porous media to identify the drying parameters and performances. It was found that most of the water contained in PHWWC is free water that is removed with a constant drying rate. The volume reduction with a marked cracks phenomenon attained 65% without any significant effect of drying temperature and sample thickness. The effective moisture diffusivity of the PHWWC for a conductive drying process is ranged between 10−9 and 1.1 × 10−8 m2·s−1. The thermal efficiency of the drying system is up to 86%. The results could be used for the purpose of design and scale-up of the industrial dryer based on laboratory-scale experiments.


2021 ◽  
Vol 11 (6) ◽  
pp. 2772
Author(s):  
Bin Li ◽  
Zhiheng Zeng ◽  
Xuefeng Zhang ◽  
Ye Zhang

To realize energy-saving and efficient industrial grain drying, the present work studied the variable-temperature drying process of corn drying in a novel industrial corn-drying system with a heat recycling and self-adaptive control function. The drying kinetics, thermal performance, heat-loss characteristics and the heat-recycling performance of the drying system under different allocations between flue gas and hot air were investigated, and the optimized drying process was proposed and compared with two constant drying processes. The results showed that the optimized drying process exhibited better drying kinetic and thermal performance than the two constant drying processes. More specifically, the total heat loss, total energy consumption and specific energy consumption of the optimized drying process were ascertained to be 36,132.85 MJ, 48,803.99 MJ and 7290.27 kJ/kg, respectively, which were lower than those of the other two processes. On the other hand, the thermal efficiency of the drying chamber for the optimized drying process was ascertained to be varied within the range of 6.81–41.71%. Overall, the validation results showed that the optimized drying process can significantly improve the drying performance of the drying system.


Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 284
Author(s):  
Ebrahim Taghinezhad ◽  
Mohammad Kaveh ◽  
Antoni Szumny

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.


Author(s):  
Amir Hossein Mirzabe ◽  
◽  
Gholam Reza Chegini ◽  

Sunflower seeds and oil in food and agricultural processing are of great importance. Dried sunflower petals are the most important parts of the sunflower plant that have economic value. Thin-layer drying experiments were performed in a laboratory scale hot-air dryer. The results indicated that with increasing drying temperature and air velocity, time of drying reduces and in most cases, the logarithmic model had the best performance for modeling the drying kinetics. The calculated values of the effective moisture diffusivity varied from 3.16627 ×10-13 to 1.32860 ×10-12 m2 s-1 and the values of the activation energy for air velocities of 0.4 and 0.8 m s-1 were equal to 51.21 and 42.3 kJ mol-1, respectively. Also, to verify whether the production and sale of sunflower petals can be cost effective, economic analysis was done. This analysis showed that drying of sunflower petals is profitable process and the generated revenue can even surpass the revenue from the sale of sunflower seeds.


Sign in / Sign up

Export Citation Format

Share Document