scholarly journals The influence of continuous and periodic microwave drying on rosemary: drying and temperature kinetics

2021 ◽  
Vol 2120 (1) ◽  
pp. 012036
Author(s):  
A Ali ◽  
B L Chua ◽  
Y H Chow
Keyword(s):  
Kinetic Study ◽  
Primary Objective ◽  
Microwave Drying ◽  
Drying Process ◽  
Pulse Ratio ◽  
Drying Kinetic ◽  
Lower Maximum ◽  
Effectiveness And Efficiency ◽  
Drying Rates ◽  
Kinetics Of

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.

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

2020 ◽  
pp. 14-14
Author(s):  
Bruna Costa ◽  
Carolina Coelho ◽  
Cássia Souza ◽  
Gabriela Duarte ◽  
Maria Pinto ◽  
...  
Keyword(s):  
Statistical Tests ◽  
Air Flow ◽  
Average Energy ◽  
Moisture Diffusivity ◽  
Pneumatic Transport ◽  
Drying Process ◽  
Brewing Industry ◽  
Transport Costs ◽  
Drying Kinetic ◽  
Kinetics Of

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.

scholarly journals Effect of blanching methods on drying kinetics of bell pepper

2011 ◽  
Vol 11 (48) ◽  
pp. 5457-5474
Author(s):  
Toyosi Tunde - Akintunde ◽  
◽  
BO Akintunde ◽  
A Fagbeja ◽  
◽  
...  
Keyword(s):  
Palm Oil ◽  
Water Movement ◽  
Drying Kinetics ◽  
Bell Pepper ◽  
Drying Rate ◽  
Drying Process ◽  
Oil Water ◽  
Drying Rates ◽  
Kinetics Of

Various blanching methods and drying temperatures were applied to bell pepper (Capiscum annum) to investigate the effect on its drying characteristics. Pepper (Capiscum annum) is an abundant and cheap source of vitamins, minerals and fibre. However, its high moisture content makes it susceptible to deterioration. The most common method of preservation is drying but the dried products obtained are of reduced nutritional qualities. Pretreatment of pepper before drying improves the quality of the dried pepper and increases its drying rate. Steam and water blanching as a form of pretreatment has been reported to increase drying rate and improve the quality of dried products but there is not much information on other types of oil/water blanching methods. The effect of blanching (steam, water, palm oil/water and groundnut oil/water) as a pretreatment on the drying kinetics of bell pepper dried at temperatures of 50, 60, 70, 80 and 90o C, was studied. Drying of raw untreated bell pepper was taken as a control. The results indicate that water removal at the initial stage of the drying process was highest and there was a rapid decrease as drying continued until equilibrium was reached at the end of process. The blanched samples generally had higher drying rates (at p<0.05) than the untreated samples. The values for the drying rate for steam and water blanched samples were higher (but not at p<0.05) than the drying rates for samples blanched in oil/water mixtures. The drying rate as well as effective moisture diffusivity, Deff, increased with increasing drying temperature. Values of Deff varied from 3.55 x 10-9 m 2/s to 2.34 x 10-9 m 2/s with the highest being SB (steam blanched) at 80oC and the lowest UB (unblanched) at 50oC. The drying process took place mainly in the falling rate period. The activation energies varied from 39.59 to 83.87 kJ/mol, with PB (palm oil/water blanched) samples having the lowest and UB having the highest Ea value. The lower values for pretreated samples imply that water movement from the internal regions is faster in pretreated samples. This suggests that blanching as a method of pretreatment generally increases water diffusion.

scholarly journals Sustainable Development of Apple Snack Formulated with Blueberry Juice and Trehalose

2021 ◽  
Vol 13 (16) ◽  
pp. 9204
Author(s):  
Juan Manuel Castagnini ◽  
Silvia Tappi ◽  
Urszula Tylewicz ◽  
Santina Romani ◽  
Pietro Rocculi ◽  
...  
Keyword(s):  
Control Sample ◽  
Solid Matrix ◽  
Vacuum Impregnation ◽  
Drying Process ◽  
Air Drying ◽  
Blueberry Juice ◽  
Drying Kinetic ◽  
Kinetics Of ◽  
Impregnation Solution ◽  
Novel Products

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.

RSM as an Approach to Optimize Ginger Intermittent Microwave Drying Process

2015 ◽  
Vol 1095 ◽  
pp. 304-308
Author(s):  
Ling Lin Zhang ◽  
Bo Wang ◽  
Li Hua Zhang ◽  
Min Zeng
Keyword(s):  
Response Surface ◽  
Process Parameters ◽  
Microwave Power ◽  
Design Theory ◽  
Polynomial Regression ◽  
Comprehensive Evaluation ◽  
Microwave Drying ◽  
Slice Thickness ◽  
Drying Process ◽  
Pulse Ratio

Based on the response surface central composite design theory, the passage discusses the effects of microwave power, slice thickness and the pulse ratio on ginger intermittent microwave drying process through response surface methodology. Simultaneously we establish quadratic polynomial regression model and optimize the drying process parameters. Results show that the influence of 3 factors on the comprehensive evaluation: The slice thickness > Microwave power > The pulse ratio. The best process parameters of ginger intermittent microwave drying is: microwave power 515W, the slice thickness 2mm, the pulse ratio 45s and the maximum comprehensive score is 0.96.

Drying Kinetics of External Thermal Insulation Composite Systems (ETICS)

2012 ◽  
Vol 326-328 ◽  
pp. 662-667 ◽  
Author(s):  
E. Barreira ◽  
João M.P.Q. Delgado ◽  
N.M.M. Ramos ◽  
V.P. de Freitas
Keyword(s):  
Moisture Content ◽  
Thermal Insulation ◽  
Kinetic Models ◽  
Second Order ◽  
Drying Kinetics ◽  
Order Kinetic ◽  
Drying Process ◽  
Composite Systems ◽  
Drying Kinetic ◽  
Kinetics Of

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.

scholarly journals Microwave Drying of Banana (Musa acuminata) Stalk Biomass before Conversion to Value-added Products

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
O. O. Agbede
Keyword(s):  
Activation Energy ◽  
Value Added ◽  
Microwave Drying ◽  
Waste Biomass ◽  
Drying Time ◽  
Effective Moisture ◽  
Thin Layer Drying ◽  
Drying Rates ◽  
Kinetics Of ◽  
Value Added Products

Banana stalk biomass can pose disposal, environmental and health challenges. Fortunately, this biomass can be converted to value-added products including biofuels, bioenergy, biosorbents, fibers and animal feeds. However, it is necessary to remove moisture from the fresh biomass by drying before storage and conversion processes. Conventional drying in open sun is slow and weather dependent, but higher heating rates and faster drying rates can be achieved in a microwave dryer. Hence, the microwave drying characteristic of banana stalk biomass was investigated. Banana stalks were sliced into 5 mm thick pieces and dried in a microwave oven at power levels of 400 – 1000 W, the stalk slices were weighed at interval until the mass remained constant. The effective moisture diffusivity, activation energy and energy required for drying were determined. The microwave drying data were also fitted to twelve thin layer drying mathematical models to describe the kinetics of the drying process. The drying time of banana stalk slices decreased with increasing microwave power. The drying occurred mainly in the falling rate period. The effective moisture diffusivities were 4.14 × 10-9 – 2.00 × 10-8 m2 s-1 at 400 – 1000 W. The activation energy was 122 W g-1 while the total and specific energies required for the microwave drying were 0.25 – 0.37 kWh and 34.8 – 51 kWh/kg, respectively. The Weibull model suitably described the microwave drying kinetics of banana stalk slices. The moisture present in fresh banana stalk waste biomass can be effectively and rapidly removed by microwave drying before conversion processes.

scholarly journals The effect of ohmic heating pretreatment on drying of apple

2018 ◽  
Author(s):  
Aslı Isci ◽  
Naciye Kutlu ◽  
Merve Silanur Yilmaz ◽  
Hicran Arslan ◽  
Ozge Sakiyan
Keyword(s):  
Thin Layer ◽  
Ohmic Heating ◽  
Order Kinetic ◽  
Drying Time ◽  
Thin Layer Drying ◽  
Drying Kinetic ◽  
Apple Slices ◽  
Order Kinetic Model ◽  
Drying Rates ◽  
Kinetics Of

In this study, effects of ohmic pretreatment on the drying rates and color kinetics of apple were investigated. Apple slices were treated at different electric field strengths (20-30 and 40 V/cm) at 60°C for 1 min. Drying process was applied at 60˚C-2 m/s by using a tray-dryer. ΔE and moisture content were calculated. These values were fitted to the semi-theoretical thin-layer drying and the zero and first-order kinetic model. The shortest drying time was found samples treated with 30 V/cm. Wang&amp;Singh model gave the superior fit to the experimental data. ΔE fitted well to the zero-order kinetic model.Keywords: Ohmic heating, drying, kinetic models, thin-layer models, apple.  

Study of color kinetics of banana (Musa cavendish) under microwave drying by application of image analysis

2020 ◽  
pp. 108201322098133
Author(s):  
Sagar Nagvanshi ◽  
Subbarao Kotra Venkata ◽  
TK Goswami
Keyword(s):  
Microwave Power ◽  
Vision System ◽  
Power Level ◽  
Microwave Drying ◽  
Slice Thickness ◽  
Order Kinetic ◽  
Drying Time ◽  
Volumetric Heating ◽  
Kinetics Of ◽  
Microwave Power Level

Microwave drying works on the volumetric heating concept promoted by electromagnetic radiation at 0.915 or 2.450 GHz. In this study, banana ( Musa Cavendish) was taken as the sample and treated under microwave drying. The effect of two process variables, namely slice thickness (2, 3.5, and 5 mm) and microwave power (180 W, 360 W, and 540 W), were studied on drying kinetics and color kinetics. It was observed that the inverse variation relationship exists between drying time and microwave power level while drying time and slice thickness exhibited a direct variation relationship. A Computer Vision System (CVS) was developed to measure the color values of banana in CIELab space using an algorithm written in MATLAB software. Once the color parameters were obtained, they were fitted in First and Zero-order kinetic models. Both models were found to describe the color values adequately. This study concludes that microwave drying is a promising dehydration technique for banana drying that reduces the significant time of drying. Application of CVS is an excellent approach to measure the surface color of banana.

scholarly journals Study on the Variable-Temperature Drying Process of Corn Drying in an Industrial Corn-Drying System Equipped with a Self-Adaptive Control Heat Exchanger

2021 ◽  
Vol 11 (6) ◽  
pp. 2772
Author(s):  
Bin Li ◽  
Zhiheng Zeng ◽  
Xuefeng Zhang ◽  
Ye Zhang
Keyword(s):  
Adaptive Control ◽  
Energy Consumption ◽  
Heat Loss ◽  
Thermal Performance ◽  
Variable Temperature ◽  
The Other ◽  
Drying Process ◽  
Drying Kinetic ◽  
Drying System ◽  
Self Adaptive

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.

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