scholarly journals Specific Energy Consumption in Convective-microwave Drying of Ashwagandha (Withania Somnifera) Roots

Author(s):  
Ashok K Senapati
2020 ◽  
Vol 15 (1) ◽  
pp. 85
Author(s):  
Arif Rahman Hakim ◽  
Wahyu Tri Handoyo ◽  
Adrianto Widi Prasetyo

Pengeringan menggunakan energi gelombang mikro menjadi alternatif agar pengeringan berjalan lebih cepat tanpa terpengaruh kondisi cuaca. Namun performa dan efisiensi energi dalam mengeringkan rumput laut belum diketahui. Tujuan penelitian ini adalah untuk mengetahui performansi pengeringan rumput laut menggunakan energi gelombang mikro (microwave) dan analisa konsumsi energinya. Metode yang digunakan ialah mengeringkan rumput laut segar dalam oven gelombang mikro secara batch. Dalam proses pengeringan dilakukan variasi level daya (400, 500, 600 watt) ke dalam oven gelombang mikro dan variasi ketebalan rumput laut (3, 5, 7 cm). Parameter yang diamati meliputi rasio kadar air (moisture ratio/MR), laju pengeringan (g/menit), difusi efektif air/Deff (mm2/detik), specific energy consumption/SEC (J/g H2O) dan efisiensi energi (%). Hasil penelitian menunjukkan, level daya magnetron 600 watt menghasilkan MR terendah (0,19), laju pengeringan tertinggi (13,15 g/menit) dan Deff tertinggi (2,28 x 10-2 mm2/detik). Rumput laut ketebalan 3 cm memperoleh MR terendah (0,05), laju pengeringan tertinggi (6,42 g/menit) dan Deff tertinggi (9,42 x 10-2 mm2/detik). SEC pengeringan sebesar 4,38-4,51 J/g H2O dan efisiensi energi 22,56-23,42% untuk level daya 400-600 watt. Perbedaaan level daya tidak memberikan pengaruh signifikan terhadap SEC dan efisiensi. Sedangkan variasi ketebalan rumput laut antara 3 cm dan 7 cm memberi hasil yang berbeda. SEC terendah diperoleh pada perlakuan rumput laut tebal 3 cm yaitu 2,96 J/g H2O sementara efisiensi tertinggi pada rumput laut dengan tebal 5 cm yaitu 22,93%.Oleh karena itu pengeringan rumput laut menggunakan energi gelombang mikro dengan level daya 600 watt dan ketebalan 3 cm menghasilkan performasi dan konsumsi energi yang lebih baik. AbstractMicrowave drying becomes alternative method to get faster process without being influenced by weather. However performance and energy efficiency of microwave drying for seaweed are still unknown. This research aims to find out performance of seaweed drying in microwave oven as well as energy consumption analysis. The method used was drying seaweed in microwave oven. Seaweed drying was conducted at various power level (400, 500, 600 watt) and thickness of seaweed (3, 5, 7 cm). Observed parameters were moisture ratio/MR, drying rates (g/min), effective diffusion/Deff (mm2/s), specific energy consumption/SEC (J/g H2O) and energy efficiency (%). Result of research showed that power level, 600 watt of magnetron produced lowest MR (0,19), highest drying rate and Deff i.e 13.15 g/min and 2.28 x 10-2 mm2/s respectively. Seaweed 3 cm thickness achieved lowest MR (0.05), highest drying rates 6.42 g/min and Deff 9.42 x 10-2 mm2/s. SEC of drying were 4.38-4.51 J/g H2O while energy efficiency were 22.56-23.42 % for 400-600 watt. Differences of power level have not given significant effect to SEC and efficiency values. Whereas differences of seaweed thickness between 3 cm and 7 cm have given significant effect. Seaweed in 3 cm thickness resulted in the lowest SEC i.e 2.96 J/g H2O, however, the highest efficiency energy was 5 cm thickness i.e 22.93%. Therefore drying seaweed utilize microwave energy of 600 watt power level and 3 cm thickness generated better performance and energy consumption.


2019 ◽  
Vol 5 ◽  
pp. 70-78
Author(s):  
Oleg Burdo ◽  
Igor Bezbakh ◽  
Serhii Shyshov ◽  
Aleksandr Zykov ◽  
Igor Yarovyi ◽  
...  

The aim of the conducted study is to determine kinetics of the complex effect of microwave energy supply and filter drying of the process of water release from the wheat layer. There is offered a combination of MW and filter drying. A special feature of this combination must be its more effectiveness and high speed of water elimination from surface layers of wet seeds and, as a result, the productivity increase of the drying way, decrease of specific energy consumption. There was determined the influence of the specific load of the material, radiator power on processes of microwave and filter-microwave drying of wheat seeds. There were compared microwave, filter-microwave and convective drying of seeds by parameters of specific energy consumption, drying speed. The specific energy consumption at microwave drying of seeds was 4 MJ/kg, at filter-microwave drying 3.8 MJ/kg that is lower than existent convective dryers. The speed of microwave drying changes from 0,5 to 3 %/min, filter-microwave – from 0.3 to 0.7 %/min. The speed is at the level of standard convective dryers. The conducted studies allow to recommend a new combined way of FMW drying of seeds with low energy consumption. Revealed features of heating and drying are possible to be used at developing industrial dryers. The base of experimental data is possible to be used for optimizing and determining effective conditions of MW and FMW drying.


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3274
Author(s):  
Klaudia Masztalerz ◽  
Jacek Łyczko ◽  
Krzysztof Lech

Background: Filtration of osmotic solution affects selective penetration during osmotic dehydration (OD), and after drying is finished, this can influence the chemical composition of the material, which is also modified by OD. Methods: Osmotic dehydration was carried out in filtrated and non-filtrated concentrated chokeberry juice with the addition of mint infusion. Then, this underwent convective drying, vacuum-microwave drying and combined convective pre-drying, followed by vacuum-microwave finishing drying. Drying kinetics were presented and mathematical models were selected. The specific energy consumption for each drying method was calculated and the energy efficiency was determined. Results and Discussion: The study revealed that filtration of osmotic solution did not have significant effect on drying kinetics; however, it affected selective penetration during OD. The highest specific energy consumption was obtained for the samples treated by convective drying (CD) (around 170 kJ·g−1 fresh weight (fw)) and the lowest for the samples treated by vacuum-microwave drying (VMD) (around 30 kJ·g−1 fw), which is due to the differences in the time of drying and when these methods are applied. Conclusions: Filtration of the osmotic solution can be used to obtain the desired material after drying and the VMD method is the most appropriate considering both phenolic acid content and the energy aspect of drying.


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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