scholarly journals Paraboloid-Based Spouted Bed Drying of Paddy: Aerodynamics, Temperature Distribution, and Moisture Degradation

2019 ◽  
Vol 1 (2) ◽  
pp. 257-264
Author(s):  
Duygu Evin

Aerodynamics, temperature variations in the annulus, and the moisture reduction of paddy in a paraboloid-based spouted bed (PBSB) dryer without draft tube and with solid and porous draft tubes were investigated. Draft tube caused a rapid decrease in the peak pressure drop and minimum spouting velocity when compared with PBSB without a draft tube. Pressure drops with draft tubes were 17 to 30% of the values for the PBSB without a draft tube. Temperature distribution along the bed height in the annular region during drying of paddy was also investigated. Heat-up in the spouted bed without draft tube was more rapid. The experiments were conducted for 70, 90, and 110 °C inlet air temperatures. The required length of drying time to dry the paddy with an initial moisture content of 0.35 db to a moisture content below 0.15 db could be reduced by 50–60% using a temperature of 110 °C instead of 70 °C. No constant rate period was observed. Drying took place in the falling rate period. Drying time decreased in the case of porous draft tube rather than the solid one. The highest drying rates were achieved by spouted bed without draft tube. Drying rates were in the range of 0.62–0.1, 0.51–0.06, and 0.37–0.06 (db.min−1) for the spouted bed without draft tube, with porous, and solid draft tubes, respectively.

Agrotek ◽  
2018 ◽  
Vol 2 (6) ◽  
Author(s):  
Wilson Palelingan Aman

<em>A research about cocoa beans drying used solar tunnel dryer with photovoltaic module driven have conducted in Manokwari. Solar tunnel dryer used in this research adapted from type Hohenheim with photovoltaic module and integrated air heat collector has been installed at the Department of Agricultural Technology, Papua State University Manokwari to dried cocoa beans. The objectives of this research were to design solar tunnel dryer and evaluate it�s performance in dryed cocoa beans. The result obtained was a new construction of solar tunnel dryer for cocoa beans with dimensions 6 m of length and 0,9 m of wide. The dryer completed with photovoltaic module to drive the blowers of hot drying air. �Performance test of the dryer showed that drying of 10 kg of cocoa beans with initial moisture content about 70% wet basis needed 13 hours of drying time to achieved final moisture content about 7,17% wet basis. The drying time achieved was faster compared than traditional solar drying that needed 20 hours of drying time. The maximum temperature achieved in drying chamber was 60 <sup>o</sup>C.</em>


2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Monika Aniszewska ◽  
Krzysztof Słowiński ◽  
Ewa Tulska ◽  
Witold Zychowicz

AbstractThe paper proposes the use of microwave irradiation to lower the initial moisture content of wood chips. The study involved willow and fir chips fractionated by means of a sieve separator and unfractionated ash chips. The wood chips were exposed to a constant microwave power of 800 W for 30 s, 60 s, 120 s and 180 s. The chips were weighed before and after irradiation to measure loss of moisture. It was found that the decline in moisture content increased with wood chip size for a given irradiation time and microwave power. The initial moisture content of wood chips was not found to significantly affect loss of moisture as the drying rates of wood chips with higher and lower moisture content exposed to microwaves were not statistically different. The results showed that irradiation intensity increased with the time of exposure to microwaves and unit radiant energy per unit of evaporated moisture decreased with increasing wood chip size in the 3.15–31.50 mm range.


Horticulturae ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 40
Author(s):  
Vincenzo Alfeo ◽  
Diego Planeta ◽  
Salvatore Velotto ◽  
Rosa Palmeri ◽  
Aldo Todaro

Solar drying and convective oven drying of cherry tomatoes (Solanum lycopersicum) were compared. The changes in the chemical parameters of tomatoes and principal drying parameters were recorded during the drying process. Drying curves were fitted to several mathematical models, and the effects of air temperature during drying were evaluated by multiple regression analyses, comparing to previously reported models. Models for drying conditions indicated a final water content of 30% (semidry products) and 15% (dry products) was achieved, comparing sun-drying and convective oven drying at three different temperatures. After 26–28 h of sun drying, the tomato tissue had reached a moisture content of 15%. However, less drying time, about 10–11 h, was needed when starting with an initial moisture content of 92%. The tomato tissue had high ORAC and polyphenol content values after convective oven drying at 60 °C. The dried tomato samples had a satisfactory taste, color and antioxidant values.


2018 ◽  
Vol 3 (2) ◽  
pp. 351-360
Author(s):  
Athul Fadhli ◽  
Diswandi Nurba ◽  
Raida Agustina

Abstrak. Jagung merupakan tanaman penghasil karbohidrat terpenting. Pengeringan jagung pipil menggunakan alat pengering merupakan proses untuk menghasilkan jagung pipil yang siap diolah untuk pembuatan tepung jagung dengan batas kadar air tertentu sehingga menghaslkan jagung pipil dengan kualitas yang baik. Tujuan penelitian ini adalah untuk mengkaji karakteristik pengeringan biji jagung menggunakan alat pengering surya Termodifikasi. Metode penelitian  menggunakan 3,15 kilogram jagung pipil dengan kadar air awal 22% untuk proses pengeringan. Parameter yang dianalisis terkait alat pengering kolektor surya yaitu temperatur, kelembaban relatif, kecepatan udara dan iradiasi surya, sedangkan parameter yang dianalisis terkait bahan yaitu kadar air, lama waktu pengeringan, laju pengeringan dan organoleptik. Prosedur penelitian terdiri dari pengujian kosong dan pengujian dengan menggunakan jagung pipil. Hasil penelitian menunjukkan bahwa temperatur rata-rata dalam rak pengering sebelum dilakukan modifikasi yaitu 44,4oC, temperatur rata-rata setelah dilakukan modifikasi yaitu 55,5oC dan temperatur rata-rata rak pengering pada pengeringan menggunakan jagung pipil yaitu 46,96oC. Kelembaban relatif rata-rata dalam rak pengering sebelum dilakukan modifikasi yaitu 40,1%, kelembaban relatif rata-rata dalam rak pengering setelah modifikasi yaitu 35,1% dan kelembaban relatif rata-rata pengeringan menggunakan jagung pipil yaitu 44,45%. Dari hasil pengukuran tersebut menunjukkan bahwa nilai temperatur dan kelembaban pada alat setelah modifikasi lebih baik dibandingkan sebelum alat dimodifikasi. Pengukuran temperatur dan kelembaban relatif terdiri dari 4 titik pengukuran yaitu rak 1A,1B dan rak 2A, 2B. Kecepatan udara rata-rata yang diukur konstan yaitu 0,7 m/s pada ruang pengering, sedangkan lingkungan 1,1 m/s. Total iradiasi surya selama pengeringan yaitu 1848,84 W/m2. Kadar air jagung pipil masing-masing rak yaitu rak 1A 14,29%, rak 1B 14,47%, rak 2A 13,91% dan rak 2B 14,1%. Hasil dari pengujian organoleptik, panelis agak menyukai jagung pipil yang dikeringkan menggunakan alat pengering tersebut.Characteristics of Seed Drying (Zea mays L.) Using a Modified Adriyarkara Solar DryerAbstract. Corn is the most important carbohydrate plant. Drying corn using a drying tool is a process to produce corn that are ready to be processed for making corn flour with a certain water content limit so as to produce corn with good quality. The purpose of this study was to examine the characteristics of drying of corn kernels using a modified solar dryer. The research method used 3,15 kilogram of corn milled with the initial moisture content of 22% for drying process. The parameters analyzed in relation to solar collector dryers are temperature, relative humidity, air velocity and solar irradiation, while the parameters analyzed are materials such as moisture content, drying time, drying rate and organoleptic. The research procedure consists of unloaded testing and testing using corn. The results showed that the average temperature in the dryer tray before modification was 44,4°C, the average temperature after modification was 55,5°C and the average temperature of the dryer tray on drying using corn was 46,96oC. The average relative humidity in the dryer tray before modification is 40,1%, the average relative humidity in the dryer tray after modification is 35,1% and the average relative humidity of drying using corn is 44,45%. From the measurement results show that the value of temperature and humidity in the tool after modification is better than before. Measurement of temperature and relative humidity consist of 4 point of measurement that is tray 1A, 1B and tray 2A, 2B. Average mean air velocity measured is 0,7 m/s at the dryer room, while the environment is 1,1 m/s. Total solar irradiation during drying is 1848,84 W/m2. Moisture level of corn each shelves tray 1A is 14,29%, tray 1B is 14.47%, tray 2A is 13,91% and tray 2B is 14,1%. As a result of organoleptic testing, panelists rather like dried corn using the dryer.


1974 ◽  
Vol 54 (3) ◽  
pp. 479-484 ◽  
Author(s):  
H. N. HAYHOE ◽  
L. P. JACKSON

Observations taken at Nappan, N.S. of drying rates of field-cured hay and the corresponding weather data are reported. Three consecutive good days were chosen as the standard for good hay drying weather. Based on 30 yr of weather records, the highest probability (36%) of having this good weather at Nappan occurs in the first 2 wk of July. Maximum production of digestible dry matter in hay occurs about mid-June. Rapid storage of high quality forage is desirable. To facilitate harvest, early cuttings of forage should be taken as ensilage. An equation is developed which relates the observed moisture content in the field to the accumulation of potential evaporation from the time of cutting. The effect of precipitation on drying time is considered. An index based on potential evaporation and precipitation is proposed as a measure of the suitability of weather data for predicting field drying rates. A good drying day is defined in terms of this index and used in the estimation of the probability of sequences of good drying days from 30 yr of weather data from Nappan, N.S.


Author(s):  
A. Narmilan ◽  
G. Niroash ◽  
M.I.M. Mowjood ◽  
A.T.A. Akram

Background: Sun drying is a popular post-harvest operation to maintain rice quality during the storage period. Farmers use different pads and thicknesses for sun drying of paddy in Ampara district, Sri Lanka. A study was conducted to evaluate the suitability and effectiveness of the drying pad and thickness as practiced by local paddy farmers during the sun drying process.Methods: The grain with an initial moisture content of 28% (dry basis) was sun dried with four types of drying pads and five levels of thickness of grain. This experiment was conducted between 8.30 am and 4.30 pm at the South Eastern University of Sri Lanka in August 2020. The moisture contents of the grain were measured at regular time intervals.Result: It was found that the duration of drying of paddy from 28% to 13% moisture content on a dry basis was 300 to 540 minutes depending upon the drying pad and thickness. The tarpaulin is reasonable at shallow thickness with less time to reach the necessary moisture level than other drying pads. Black polythene and fertilizer bag can be utilized for sun drying of paddy at 4 cm thickness with 130 minutes. It was found that with an increase in the thickness of paddy from 0.5 cm to 4 cm, the drying time increases. A statistically significant interaction was obtained between drying pads and thickness level on moisture removal of paddy. Therefore, the moisture removal rate differs with the drying pad and thickness of the paddy under open sun drying.


2020 ◽  
Vol 50 (1) ◽  
pp. 79-86
Author(s):  
Elena Verboloz ◽  
Marina Ivanova ◽  
Vera Demchenko ◽  
Sergey Fartukov ◽  
Nikita Evona

Introduction. Rose hips are rich in macro- and micronutrients. Unfortunately, heat treatment destroys most nutrients. Ultrasonic technologies make it possible to reduce the drying time and lower the temperature regime. The research objective was to adjust ultrasound technology to rose hip production in order to reduce the loss of vitamins and improve the quality indicators of the dried product. Study objects and methods. The research featured rose hips of the Rosa canina species collected in the south of Kazakhstan. This subspecies of wild rose is poor in vitamin C. Nevertheless, this shrub is extremely common in Russia and other countries of the Commonwealth of Independent States. The raw material was dried according to standard methods. One group of samples was treated with ultrasound, while the other served as control. Both groups underwent a sensory evaluation and were tested for moisture and vitamin C. Results and discussion. The rose hips were dried in a combination steam oven with a built-in ultrasonic wave generator. The research revealed the following optimal parameters of the ultrasound drying process: frequency of ultrasonic vibrations – 22 kHz, processing time – 2.5 h, temperature in the combination steam oven – +56°C, initial moisture content – 30%. The resulting product met the requirements of State Standard. The loss of moisture was 57%. According to State Standard 1994-93, the initial moisture content should be 15% or less. Time decreased from 360 min to 160 min, and the initial moisture was 13%. The experiment confirmed the initial hypothesis that ultrasonic treatment improves the drying process by improving quality indicators and preserving vitamin C in raw materials using. Conclusion. Ultrasound treatment during moisture removal from rose hips provides a resource-saving technology that fulfills an economically and socially important function.


2020 ◽  
Vol 154 ◽  
pp. 01004
Author(s):  
Ewa Golisz ◽  
Małgorzata Jaros ◽  
Szymon Głowacki

The goal of the work was to propose and verify the model of temperature changes of the convective dried biomass depending on the drying time. The algebraic temperature model of the convective dried solid, giving the possibility of its direct calculation, was based on the logistic function of growth. Temperature model was verified for convective dried biomass: vegetable and wood (poplar and willow wood chips) significantly differing in initial moisture content. Parameter W in the temperature model, defined as the coefficient of temperature rate changes reaches greater values in higher temperature of drying air and for wood biomass which has lower initial moisture content. Empirically selected parameter W allows to verify the temperature model with the relative error less than 5%.


Author(s):  
Eoin Fanning ◽  
Tim Persoons ◽  
Darina B. Murray

The evolution of the mass transfer rate and temperature of a porous body in a convective drying process shows two main stages: A constant-drying rate period and a falling-drying rate period. This study investigates the simultaneous time evolution of moisture content and local surface temperature of a porous cube inside a rectangular flow channel for a range of air flow temperatures and Reynolds numbers. The moisture content is measured using a precision mass balance. Local surface temperature distribution is measured using a thermal imaging camera. In the constant-drying rate period, an average Nusselt number in the range 7.1 ≤ Nu ≤ 13.3 and an average Sherwood number of 4.7 ≤ Sh ≤ 6.0 are calculated for a Reynolds number range of 180 ≤ Re ≤ 595. Infrared thermography shows that the falling-drying rate period begins, the temperature distribution becomes non-uniform and approaches the temperature of the surroundings. This transition occurs first near the edges of the cube and, in particular, near the leading edge of the cube, as witnessed in previous studies.


Author(s):  
C. M Badgujar ◽  
O. S. Karpe ◽  
S. R. Kalbande

A commercial solar tunnel dryer (STD) was evaluated for drying of sprouted moth beans and also its techno-economic analysis was carried out. The maximum temperature 58ºC was recorded at 13:00h in STD during the drying process i.e. 41.0% (34.2ºC) higher than the maximum ambient temperature at the same time. A total drying time of 13:50h were required in STD to reduce the initial moisture content from 177.7% dry basis (d.b) to a final moisture content of 16.6% (d.b). However, the open sun drying took 16.5 drying hours to obtain desired moisture content. The net present worth and cost-benefit ratio of dryer was Rs.5,83,910.68/- and 1.19, respectively. However, the payback period for STD was 15 month 8 days. The cost economics of dried products were proved better for STD than open sun drying method. STD samples were found to be of good quality in terms of color, taste and aroma as compared to open sun dried (OSD) with an overall drying efficiency of STD was 19.7%. Therefore, the evaluated solar tunnel dryer were recommended for the drying of sprouted moth beans.


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