scholarly journals Investigation of some pretreatments on energy and specific energy consumption drying of black mulberry

2013 ◽  
Vol 19 (1) ◽  
pp. 89-105 ◽  
Author(s):  
Esmaeili Adabi ◽  
Ali Motevali ◽  
Ali Nikbakht ◽  
Hadi Khoshtaghaza

Massive consumption of energy in drying industry makes it a matter of challenge regarding economical aspects and limited recourses. Several methods for drying including hot air convection, vacuum, infrared and hot air convection-infrared technologies were applied in order to estimate the consumed energy during the drying of mulberry fruit. Moreover, microwave heating, chemical (ethyl oleate and potassium), mechanical (ultrasonic) and blanching (hot water) pretreatments were compared. According to the Results, maximum energy consumption was recorded when no pretreatment was performed. Microwave heating in the hot air convection-infrared dryer resulted in the lowest consumption of energy. Total energy requirement decreased with the temperature in the convection dryer res. Conversely, energy increased with air velocity. The vacuum dryer consumed the highest amount of energy which was measured to be 46.95 kWh while the lowest energy was recorded with using infrared-convective dryers. Also Experimental results showed that minimum and maximum specific energy consumption in the drying of black mulberry were associated with microwave pretreatment in IR-hot air dryer and control treatment in vacuum dryer, respectively. The minimum color change (?E) for drying of black mulberry was found in microwave pretreated samples dried with the vacuum dryer, yet maximum ?E was observed in hot air dryer when no pretreatment was applied.

2019 ◽  
Vol 801 ◽  
pp. 345-350
Author(s):  
Ratinun Luampon ◽  
Sungwarn Bunchan ◽  
Bundit Krittacom

This research was proposed to applying stainless wire mesh porous material for specific energy consumption improvement of a hot air dryer. In experimental consist two main parts, first part was a comparison of drying with and without hot air recirculation duct. Second part was a comparison of drying with and without stainless wire mesh porous material in drying chamber and hot air recirculation duct. Tilapia was drying product, stainless wire mesh in drying chamber was constant PPI=8 and 6 layers, stainless wire mesh in hot air recirculation duct was constant PPI=8 and varied layer at 6, 8 and 12 layers and hot air recirculation ratio 40%, 60% and 80%. Experimental result was, drying with hot air recirculation duct was higher drying rate than without recirculation duct and drying rate was increased, drying time was decreased and SEC was decreased with increased hot air recirculation ratio. At recirculation ratio 80%, SEC was lowest and decreased to 54.52% compared with without recirculation duct. Therefrom, the stainless wire mesh porous materials were inserted in the drying chamber and recirculation duct at PPI=8, 6 layers and PPI=8, 12 layers, respectively and used recirculation ratio 80%, it was found that SEC was lowest and decreased as about 62.21%.


2018 ◽  
Vol 5 (3) ◽  
pp. 372-387 ◽  
Author(s):  
Mohammad Kaveh ◽  
Vali Rasooli Sharabiani ◽  
Reza Amiri Chayjan ◽  
Ebrahim Taghinezhad ◽  
Yousef Abbaspour-Gilandeh ◽  
...  

2016 ◽  
Vol 14 (4) ◽  
pp. 11-18
Author(s):  
N. Deliiski ◽  
N. Trichkov ◽  
Z. Gochev ◽  
D. Angelski

Abstract A mathematical model and a numerical approach for the computation of the specific energy consumption, which is needed for warming up of flat furniture elements before their lacquering, have been suggested. The approach is based on the integration of the solutions of a non-linear model for the calculation of the nonstationary 1D temperature distribution along the thickness of subjected to unilateral convective heating furniture elements. With the help of a self-prepared software program, computations have been carried out for the determination of the change in the specific energy, which is consumed by oak furniture elements with an initial temperature of 20 °C, moisture content of 8 %, thickness of 16 mm, and length of 0.6 m, 1.2 m, and 1.8 m, during their 10 min unilateral convective heating by hot air with temperature of 100 °C and velocity of 5 m·s−1.


2012 ◽  
Vol 622-623 ◽  
pp. 1135-1139 ◽  
Author(s):  
A. Ekphon ◽  
T. Ninchuewong ◽  
S. Tirawanichakul ◽  
Y. Tirawanichakul

The main objective of this research was to study drying kinetics of air dried sheet (ADS) rubber using hot air and simulated drying kinetics by empirical model compared to experimental results. The 10-15 fresh rubber sheet with initial moisture content ranging of 23-40% dry-basis was dried by temperature of 40-70°C and air flow rate of 0.7 m/s. The fresh rubber sheet samples were dried until the desired final moisture content reached to 0.15% dry-basis. The experimental results showed that the drying rate of ADS rubber dried with hot air convection was faster than conventional natural air convection and drying rate was related to drying temperature. The experimental data was statistical non-linear regression analyzed by using 10 conventional empirical models. The coefficient of determination (R2) and root mean square error (RMSE) values were used as the criteria for selecting the best equation to describe the experimental data The results showed that the calculated results of Verma et al.’ model had a good relation to the experimental results. For specific energy evaluation, the results showed that at high drying temperature specific energy consumption of ADS rubber was relatively low compared to drying with low temperature. Finally, the determination of physical quality showed that.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hany S. EL-Mesery ◽  
Mona A. Elabd

Abstract Okra pods were dried using the following drying regimes; microwave (MWD), infrared (IRD) and convective hot-air drying (CHD). The objective of this investigate was to report the influences of drying methods on okra quality under different drying conditions. Data analysis showed that rehydration ratio and colour change increased with increase in drying air temperature and air velocity while specific energy consumption and shrinkage ratio decreased with increase in drying air temperature under (CHD). The rehydration ratio and colour of dried okra increased with increase in both infrared intensity but it also increased with a decrease in air velocity under (IRD). In the MWD method, drying time, specific energy consumption and shrinkage ratio decreased with increases in microwave power while the rehydration ratio and colour increased. Optimum drying period, specific energy consumption, colour, shrinkage and rehydration ratio were obtained for microwave drying. The model of Midilli et al. is the greatest for describing the drying curves of okra under all the drying processing conditions.


Author(s):  
C. N. Okoro ◽  
J. Isa

This research is concerned with the energy performance analysis of convective drying of sorghum gruel residue. The process was carried out on a hot air dryer conducted at four drying air temperatures of 40, 50, 60, and 70 °C respectively, three different air velocities 0.8, 1.0 and 1.2m/s and three different varieties of sorghum gruel residue, Caudatum,Durra and Guineense respectively. The effects of drying temperature and air velocities on the specific energy consumption, energy efficiency, drying efficiency and thermal efficiency were investigated. The specific energy consumption for Caudatum,Durra, Guineensevarieties ranges from 169530.001 J/kg - 71433.758 J/kg, 170557.25 J/kg - 76732.96 J/kg and 179367.266 J/kg - 83750.923 J/kg respectively while the energy efficiency for Caudatum,Durra, Guineensevarieties ranges from 35.5% - 13.934%, 31.188% - 13.836% and 28.463% - 13.157% respectively. The results of this study also confirmed that the convective drying process is energy intensive and drying fresh agricultural produce with heated-air dryers requires a relatively large amount of energy.


1970 ◽  
Vol 26 (1) ◽  
pp. 16 ◽  
Author(s):  
S Balasubramanian ◽  
Rajkumar Rajkumar ◽  
K K Singh

Experiment to identify ambient grinding conditions and energy consumed was conducted for fenugreek. Fenugreek seeds at three moisture content (5.1%, 11.5% and 17.3%, d.b.) were ground using a micro pulverizer hammer mill with different grinding screen openings (0.5, 1.0 and 1.5 mm) and feed rate (8, 16 and 24 kg h-1) at 3000 rpm. Physical properties of fenugreek seeds were also determined. Specific energy consumptions were found to decrease from 204.67 to 23.09 kJ kg-1 for increasing levels of feed rate and grinder screen openings. On the other hand specific energy consumption increased with increasing moisture content. The highest specific energy consumption was recorded for 17.3% moisture content and 8 kg h-1 feed rate with 0.5 mm screen opening. Average particle size decreased from 1.06 to 0.39 mm with increase of moisture content and grinder screen opening. It has been observed that the average particle size was minimum at 0.5 mm screen opening and 8 kg h-1 feed rate at lower moisture content. Bond’s work index and Kick’s constant were found to increase from 8.97 to 950.92 kWh kg-1 and 0.932 to 78.851 kWh kg-1 with the increase of moisture content, feed rate and grinder screen opening, respectively. Size reduction ratio and grinding effectiveness of fenugreek seed were found to decrease from 4.11 to 1.61 and 0.0118 to 0.0018 with the increase of moisture content, feed rate and grinder screen opening, respectively. The loose and compact bulk densities varied from 219.2 to 719.4 kg m-3 and 137.3 to 736.2 kg m-3, respectively.  


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