scholarly journals Drying Performance of Beans Using Natural Convective Step Type Solar Dryer

Author(s):  
S. Joshua Davidson ◽  
J. John Gunasekar ◽  
K. Prasanthkumar

Development of appropriate technologies for conversion of solar radiation to thermal energy is essential for fruit and vegetable preservation. A natural convective step type solar dryer with 10 trays was used. The drying parameters such as drying temperature, drying rate and dryer efficiency were studied on bright sunny days from top to bottom of the dryer using unblanched and blanched beans. The maximum and minimum temperatures observed were 84ºC and 50ºC at no load, 59ºC and 75ºC using unblanched beans and 51 and 75ºC using blanched beans. While drying on a sunny day, the moisture content removed was from 72 to 14% for unblanched beans and 76 to 7.32% for blanched beans. On quality evaluation, the high rehydration coefficient was found in blanched beans (0.76) than in unblanched beans (0.52). The collection efficiency was found to be 40.92% and drying efficiency was found to be 15.85% using unblanched beans and 18.75% using blanched beans.

2020 ◽  
Vol 13 (2) ◽  
pp. 42-58
Author(s):  
Andi Muhammad Irfan ◽  
Arimansyah Arimansyah ◽  
A. Ramli Rasyid ◽  
Nunik Lestari

Abstrak. Penelitian ini bertujuan untuk menguji unjuk kerja pengering tenaga surya tipe efek rumah kaca pada pengeringan cabai dengan perlakuan low temperature long time (LTLT) blanching. Selain itu, pada penelitian ini juga dilakukan kajian mengenai karakteristik pengeringan cabai yang dipengaruhi oleh perlakuan LTLT blanching, terutama pada kadar air, laju pengeringan, kecepatan pengeringan, dan kualitas warna. Pengujian dilakukan dengan cara mengeringkan cabai merah dengan pretreatment LTLT blanching yang dikombinasikan dengan perlakuan merotasikan rak pengering (R) dan tanpa merotasikan rak pengering (TR). Sebagai kontrol adalah cabai yang dikeringkan tanpa blanching dan tanpa merotasikan rak pengering (K). Hasil penelitian menunjukkan bahwa perlakuan LTLT blanching yang dikombinasikan dengan merotasikan rak pengering (R) merupakan perlakuan yang terbaik, dengan kadar air akhir cabai kering sebesar 9,82% dan sesuai dengan standar SNI. Waktu pengeringan yang dibutuhkan adalah selama 5 hari. Warna cabai kering yang dihasilkan adalah yang terbaik dari dua perlakuan lainnya, dengan nilai L*, a*, dan b* untuk setelah proses LTLT blanching (sebelum proses pengeringan) dan setelah pengeringan berakhir (cabai kering) berturut-turut adalah 36,02, 38,22, 13,62, dan 32,44, 33,89, dan 10,19. Energi yang terpakai untuk pengeringan cabai adalah sebesar 596181 kJ. Perlakuan R ini juga menghasilkan efisiensi pengeringan terbaik, yaitu sebesar 34,01%.Performance of Green House Effect Type Solar Dryer in the Chillies Drying with Low Temperature Long Time Blanching TreatmentAbstract. This study aims to examine the performance of the greenhouse effect type solar dryer on drying chillies with low temperature long time (LTLT) blanching treatment. In addition, a study was also conducted on the characteristics of drying chillies and the final product affected by LTLT blanching treatment, especially in terms of moisture content, drying rate, drying speed, and color. Testing was performed by drying red chilli with LTLT blanching treatment, which was combined with the treatment of rotating dryer rack (R) and without rotating dryer rack (TR). As a control, chillies were dried without blanching treatment and without rotating dryer rack (K). The results show that the LTLT blanching treatment combined with rotating the drying rack (R) is the best treatment, with a final moisture content of 9.82% which is in accordance with SNI standards. The drying time needed is 5 days. The dried chilli color produced is the best of the other treatments, with values of L*, a*, and b* for after the LTLT blanching process and after drying ended, respectively 36.02, 38.22, 13.62, and 32.44, 33.89, 10.19. The energy used for drying chillies is 596181 kJ. This R treatment also produces the best drying efficiency, which is 34.01%.


2012 ◽  
Vol 2 (1) ◽  
pp. 14-20
Author(s):  
Yuwana Yuwana

Experiment on catfish drying employing ‘Teko Bersayap’ solar dryer was conducted. The result of the experiment indicated that the dryer was able to increase ambient temperature up to 44% and decrease ambient relative humidity up to 103%. Fish drying process followed equations : KAu = 74,94 e-0,03t for unsplitted fish and KAb = 79,25 e-0,09t for splitted fish, where KAu = moisture content of unsplitted fish (%), KAb = moisture content of splitted fish (%), t = drying time. Drying of unsplitted fish finished in 43.995 hours while drying of split fish completed in 15.29 hours. Splitting the fish increased 2,877 times drying rate.


2016 ◽  
Vol 12 (6) ◽  
pp. 599-606 ◽  
Author(s):  
Flávia Daiana Montanuci ◽  
Raphaela Mulato Cavalcante ◽  
Camila Augusto Perussello ◽  
Luiz Mario de Matos Jorge

Abstract The study of process kinetics may aid the design and optimization of drying systems. This paper evaluated the influence of drying temperature (40, 60 and 80 °C) on the moisture content, drying rate, density, shrinkage and breakage of maize dried in two different dryers: oven and silo dryer. In both dryers, the temperature increase reduced drying time, final moisture content and shrinkage of the grains, however increased breakage. Drying rate was higher in the oven (6.4×10−4±2.3×10−4s−1 versus 5.4×10−4±1.2×10−4s−1), while shrinkage (15.2±4.7 % versus 24.4±5.6 %) and density increase (16.6±5.9 % versus 33.4±5.8 %) were more intense in the silo. There was a large release of husk in the silo dryer and the moisture content was slightly smaller in the lower layers respective to the upper ones.


2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Masnaji R. Nukulwar ◽  
Vinod B. Tungikar

Abstract The objective of this study is to find an optimized thin-layer mathematical model suitable for drying kinetics of turmeric. Turmeric has a high moisture content which necessitates effective drying. A 10 kg, sample batch, of turmeric was dried in a solar dryer. Drying air temperatures and air velocity were observed in the range of 55 °C–68 °C and 0.7 m/s–1.4 m/s, respectively, in the drying experiments. It is seen that the moisture content of the turmeric is reduced from 77% to 11.93% in 22 h when compared with open sun drying, which required 60 h for the same reduction in the moisture content. Scheffler dish was used to generate steam for the dryer. Seven thin-layer mathematical models, cited in the literature, had been used for the study. These models were applied for different trays placed in the dryer. The result of the research and experimentation showed that the Page model fits best for drying in the steam-based dryer and open sun drying. Experimental results showed 63.33% saving in drying time, and the drying efficiency was found as 29.85%. Uncertainty in the drying efficiency was observed as 0.67%. Experimental investigation and the findings from the mathematical modeling are presented in this paper.


2019 ◽  
Vol 15 (8) ◽  
Author(s):  
Qinqin Chen ◽  
Huihui Song ◽  
Jinfeng Bi ◽  
Ruijuan Chen ◽  
Xuan Liu ◽  
...  

AbstractOptimum technology and quality evaluation of short- and medium-wave infrared radiation (SMIR) dried carrot slices were studied. Effects of drying temperature, drying time and infrared power of SMIR drying on the moisture content, color parameter and β-carotene content of dehydrated carrot slices were investigated. The experimental data were well predicted by a modified second-order polynomial model. Drying temperature and drying time had significant effects on moisture content, color parameter and β-carotene content. However, infrared power only showed significant effect on the moisture content. Response surface method (RSM) was used for optimization of SMIR drying of carrot slices, and the optimum condition was found as drying time of 50 min, infrared power of 1125 W, and drying temperature of 70 °C. SMIR dried products were proved to be favorable by comparing with hot-air dried ones due to its higher rehydration ratio (6.89) and β-carotene content (462.48 μg/g).


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.


2011 ◽  
Vol 308-310 ◽  
pp. 1586-1589
Author(s):  
Xing Zao Ma ◽  
Chang You Li ◽  
Li Li Zhang ◽  
Wen Hao Shen

In this paper, the deep-bed drying rate was analyzed under different bed depths and air temperatures. It was found that the bed depth had a greater impact on the drying efficiency, and if the initial moisture content of maize and the ventilation temperature are higher, the effect would be much more notable. The results will provide a basis for optimal design of the deep-bed drying devices.


Adjustable Multi glazing solar drying system is designed and fabricated for experimental study. The arrangement is made in the present model such that it can be wok as a single glazing, double glazing and multi-glazing solar dryer by adjusting the plain window glass (Glazing). The performance analysis and comparison of Single glazing (SGSD), double glazing (DGSD) and Triple pass solar drying system (TPSD) have been conducted by using red chilli. The performance curves show the effect of solar intensity on the collector efficiency, drying efficiency and pick-up efficiency of solar drying system. The collector efficiency of TPSD increased by 28.8% and 53% as compared to DGSD & SGSD respectively at average value of solar radiation 674.4 W/m² at 26.90 gm per second of air mass. The initial moisture content in red chili was measured and found 78.8 (wb) reduced to minimum moisture content 9.8% (wb). It could be concluded that, the time required to dry the red chilli in TPSD is minimum as compared to SGSD and DGSD.


AGROINTEK ◽  
2020 ◽  
Vol 14 (2) ◽  
pp. 180-190
Author(s):  
Asri - Widyasanti ◽  
Nedia Cahyati Muchtarina ◽  
Sarifah - Nurjanah

The needed for tomatoes was not comparable with the abundant of production, so tomato prices at the farm level were low. Tomato processing was needed to maintained and increased the selling value of tomatoes, it can be processed into tomato pulp powder. Tomato powder can be made by foam-mat drying method and to shortened the drying time can be done by using microwave oven. The purpose of this study was to determine the effect of the drying power used on physicochemical properties of tomato pulp powder and drying rate of foam-mat drying with microwave oven. This study conducted with laboratory experimental method with descriptive analysis. Three repetitions consisted of three treatments based on drying power used (30%, 50% and 70%). The observed parameters were total yield value, color, drying rate, drying efficiency and physicochemical properties such as color, foam density, bulk density, moisture content, ash content, water absorption index, and vitamin C content. The results showed that the average moisture content of tomato pulp was 91.73% (w.b.) and foamed tomato pulp was 90.86% (w.b.). The value of water content of tomato pulp powder ranges from 9.18% (w.b.) to 12.50% (w.b.). In this study, the best results were found in tomato pulp powder with 70% drying power without addition foaming treatment with total yield of 0.58%; 4.26 g/min drying rate; 5.86%; foam density 1 g/cm3; bulk density 0.65 g/cm3; moisture content; 9.18%; ash content 6.43%; water absorption index 19.68%; vitamin C content 154.87 mg/100g and drying efficiency was 48.27%. All of drying power used with and without foaming treatment were resulting yellow-red chromatic colour characteristic.


Author(s):  
A. A. Ijah ◽  
O. E. Olagunju ◽  
S. M. Adamu ◽  
H. C. Ozoani ◽  
F. M. Rasheed ◽  
...  

Corn as a staple farm produce are usually harvested at a point or time when the moisture content is more than 25% (wet.basis).,and therefore, it is easily attacked by fungi and other diseases causing organism and even physical damage, thereby reducing the market value of the crop.  Drying must be carried out on those products to prevent deterioration. The objectives of this research are to develop a device that can reduce the moisture content of corn using electronic components and equally carryout evaluation on the device.  Shelled corns with initial moisture content of between 25-30% (w.b.) is the major material used in this research work. A Heating element incorporated in the device supplied the needed heat which was delivered to the drying chamber by the help of a centrifugal blower. The drying experiment was carried out at three different temperature thus; 45 oC, 55 oC and 65oC. The moisture content at this varying temperature was used to determine the drying rate and the drying efficiency. The results showed clearly that the dryer air temperature affect the drying rate, the efficiency of drying, and the quality of the material. It is equally clear that the best drying rate and temperature is  65oC average 4,95% / hour, high efficient at drying temperature 55oC and 65oC equal to 86,27% and 83,51%, and best material quality with dryer temperature 55oC.


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