Evaluation of the Performance of a Custom-Made Fluidized Bed Drying System

2018 ◽  
Vol 34 (6) ◽  
pp. 1027-1037 ◽  
Author(s):  
Sammy S. Sadaka ◽  
Kaushik Luthra ◽  
Griffiths G. Atungulu

Abstract. Laboratory and farm-scale fluidized bed dryers are not available to purchase. Additionally, a deliberation is presently continuing regarding the beneficial and damaging effects of drying grain in a fluidized bed. Therefore, the goal of this research was to develop and test a custom-made small-scale fluidized bed dryer, suitable for moderate farms and capable of drying small and large size grains from high moisture content to a safe storage moisture content. The customary fluidized bed dryer was developed and constructed in the Rice Research and Extension Center, Stuttgart, Arkansas. The fluidized bed dryer was used to dry wheat from an initial moisture content of 23.3% db. The effects of the aspect ratio (bed height to bed diameter ratio) of 2, 3, and 4 m/m, the furnace temperature of no heat, 100°C, 150°C, and 200°C and drying duration of 10, 20, 30, 40, 50, and 60 min on the wheat moisture content, drying rate, and dryer efficiency were investigated. The lowest wheat moisture content of 16.3% db was observed at the lowest aspect ratio of 2 m/m, the highest furnace temperature of 200°C, and the longest drying duration of 60 min. Conversely, the highest wheat moisture content of 19.0% db was observed at the highest aspect ratio of 4 m/m, and the no heat condition. The drying rate of 0.47%/min was observed at the lowest aspect ratio of 2 m/m and the furnace temperature of 200°C after 10 min. The maximum dryer efficiency of 63.2% was achieved at the aspect ratio of 4 m/m, the furnace temperature of 200°C. Two empirical models were developed to predict the moisture content of wheat and the dryer efficiency as affected by the aspect ratio, the furnace temperature and the drying duration with the adjusted coefficient of determination of 0.91 and 0.88, respectively. Although, the developed fluidized bed dryer is a lab-scale system, the experimental results provided an exceptional indication to scale up the drying system to dry grains. Keywords: Dryer efficiency, Drying rate, Fluidized bed, Moisture content, Wheat-drying.

Today many industries now use the dryer as a part of grain-drying process even during wet and dry seasons. This helps in reducing spoilage and wastage of paddy. Mostly the available industrial dryers are expensive to purchase and to maintain its smooth functioning. This study therefore is a step to design a simple Plug flow fluidized dryer that can lead to introduce small scale dryers to paddy process industry. The Plug flow fluidized bed dryers are designed and fabricated in this study consists of the drying chamber, hot air distributer plate, hot air inlet and exit system, paddy entry and exit system, fluidization chamber unit with temperature control unit and the centrifugal fan. The evaluation of dryer is based on drying time and reduction in moisture content and outlet temperature of paddy on quality parameters. Dryer dimensions are very important to analyze heat and mass transfer analysis of the Plug flow fluidized bed drying process of paddy grains. It was found d that heat and mass transfer properties of paddy grains in fluidized bed dryer was decreases as the time of drying passes and very rapid at the start of drying. The model present here predicts about dryer dimensions along safe zone of rough rice moisture content with other parameters. Simulation results show a good agreement between the simulation model and the existing simulation models


2017 ◽  
Vol 2 (6) ◽  
pp. 430 ◽  
Author(s):  
Suherman Suherman ◽  
Mohammad Djaeni ◽  
Dyah Hesti Wardhani ◽  
Andri Cahyo Kumoro

The objective of this research is to develop the industrial-scale fluid bed dryer for paddy by scale-up of lab-scale experimental data. The developed dryer was conducted by simulation using a two phase model. Firstly, the experimental works by using lab-scale batch fluid bed dryer, was conducted to determine the drying curve of paddy (Xin 0.32 kg/kg dry base). In the experimental works,the inlet air temperature was varied (°C): 40; 50; 60. The drying rate curves as a function of moisture content showed only decreasing drying rate period. Then, a very good agreement between the measured and simualtion results of the profile of moisture content in solids was produced by simulator. Finally, asimulated continuous fluidized bed dryer for paddy with dimension 5 m of length and 1.5 of width was succesfully performed, in which the influence of mass solid flow rate 0.1; 0.2; 0.4 tons/h, height of bed 0.25; 0.50; 0.75 m, and air temperature 50; 70; 100 °C on drying process were studied. Keywords: Paddy; fluid bed dryer; batch, contonious;  modelling; simulation


2014 ◽  
Vol 11 (1) ◽  
pp. 153-158 ◽  
Author(s):  
M Akhtaruzzaman ◽  
MR Ali ◽  
MM Rahman ◽  
MS Ahamed

The fluidized bed drying principles for drying of tea in Bangladesh is thoroughly studied. The experiments were conducted to determine the drying curve, drying time, drying constant and dynamic equilibrium moisture contents of tea at the Bangladesh Tea Research Institute. Drying of tea in a fluidized bed dryer (Kilburn Vibro Fluid Bed Dryer) takes only 20 min for drying from an initial moisture content of 69.1% to a final moisture content of 2.8%. Temperatures of drying air were recorded to be 130°C at the inlet and 90°C at the outlet. The drying constant was found to be 31.05 h-1 and the dynamic equilibrium moisture contents were in the range of 18.3 to 2.0%. Finally the principle of fluidized bed drying was compared with the principle of conventional endless chain pressure type drying. DOI: http://dx.doi.org/10.3329/jbau.v11i1.18227 J. Bangladesh Agril. Univ. 11(1): 153-158, 2013


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.


Author(s):  
JO Akowuah ◽  
HA Boateng ◽  
G Obeng Akrofi ◽  
DE Maier

The technical performance of a 3-tonne capacity flatbed grain dryer was assessed based on its drying rate and drying efficiency. In addition, the quality of maize grains dried in the drying system was investigated through stress-crack analysis and germination test. Maize grains at an initial moisture content of 18.4% ± 0.1% (wb) were dried to a safe moisture content of 13.3% ± 0.2% (wb) in 5 hours, resulting in a drying rate of 1.02%/h at a drying efficiency of 67.35%. The average temperature observed in the plenum (55.8°C±1.5°C) was about twice higher than the ambient temperature during the drying period. The use of the flatbed dryer did not have any adverse effect on the viability of grains dried with a stress-crack index of 75 and percentage germination of 90%. This study demonstrated the viability of using the flatbed biomass-assisted dryer for drying maize and can reduce post-harvest losses of maize at the smallholder level. Int. J. Agril. Res. Innov. Tech. 11(2): 37-41, Dec 2021


2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
M. Yahya

The performances of a solar assisted fluidized bed dryer integrated biomass furnace (SA-FBDIBF) and a solar assisted heat pump fluidized bed dryer integrated biomass furnace (SAHP-FBDIBF) for drying of paddy have been evaluated, and also drying kinetics of paddy were determined. The SA-FBDIBF and the SAHP-FBDIBF were used to dry paddy from 11 kg with moisture content of 32.85% db to moisture content of 16.29% db (14% wb) under an air mass flow rate of 0.1037 kg/s within 29.73 minutes and 22.95 minutes, with average temperatures and relative humidities of 80.3°C and 80.9°C and 12.28% and 8.14%, respectively. The average drying rate, specific energy consumption, and specific moisture extraction rate were 0.043 kg/minute and 0.050 kg/minute, 5.454 kWh/kg and 4.763 kWh/kg, and 0.204 kg/kWh and 0.241 kg/kWh for SA-FBDIBF and SAHP-FBDIBF, respectively. In SA-FBDIBF and SAHP-FBDIBF, the dryer thermal efficiencies were average values of 12.28% and 15.44%; in addition, the pickup efficiencies were 33.55% and 43.84% on average, whereas the average solar and biomass fractions were 10.9% and 10.6% and 36.6% and 30.4% for SA-FBDIBF and SAHP-FBDIBF, respectively. The drying of paddy occurred in the falling rate period. The experimental dimensionless moisture content data were fitted to three mathematical models. Page’s model was found best to describe the drying behaviour of paddy.


2021 ◽  
Vol 29 (3) ◽  
Author(s):  
Nur Tantiyani Ali Othman ◽  
Ivan Adler Harry

Sago is an essential source of starch for some regions in the third and developing world. However, the sago processing industry has been producing a large amount of sago waste, and the untreated waste is usually disposed to the nearest river. It not only leads to the environmental problem, but it is illegal under the Environmental Quality Act 1974. Since the sago waste still has high starch content, which is 58%, it can be converted to high value-added products such as poultry feed. However, before being converted to other products, the sago must be dried to remove the moisture content to prevent any bacteria growth and ensure safety health issues have been observed. Recently, drying of sago bagasse using a fluidized bed dryer (FBD) has gained attention since the dry rate of the material is considerably faster compared to other methods. Due to that reason, the drying of the sago bagasse in the FBD is studied using computational fluid dynamic as it can be executed in a short period of time compared to the experimental approach. The FBD model was developed using ANSYS© Fluent academic version 19.2. The effect of the hot air feed temperature; T=50, 60, 70, and 80°C and velocity of hot air feed; v=1-4 m/s on the sago’s behavior and performance of fluidization profile were studied. The simulation results showed that the high temperature and air feed velocity would result in a rapid drying rate. Besides, the optimum drying rate was at T=60°C with the v=4 m/s as these conditions give a shorter drying time to achieve of final 10% moisture content. It also has the added advantages of reducing the power energy and cost supply. These optimal conditions are very crucial and should be consider as the dried sago bagasse tend to be retrograded when a higher temperature is applied.


2008 ◽  
Vol 4 (6) ◽  
Author(s):  
Law Chung Lim ◽  
Wan Ramli Wan Daud

Advanced drying technology enables drying of rough rice and dedusting of rice husks to be carried out simultaneously in the same unit processor. This paper reports the efficiency of dedusting of rice husks in a two-stage inclined cross flow fluidized bed dryer and the drying kinetics of rough rice in a batch fluidized bed dryer as well as the conceptual design of a hybrid drying – dedusting unit processor. Experimental works had been carried out using rough rice (a Group D particle according to Geldart classification of powders) in a 2.5 m height two-stage inclined fluidized bed column of cross sectional area of 0.61m x 0.15m and a 3 m high batch fluidized bed dryer. The objectives of the study was to investigate the separation efficiency of dedusting of rice husks in the two-stage cross flow fluidized bed dryer and to study the drying kinetics of rough rice drying in the batch fluidized bed dryer. The experimental results showed that the dedusting separation efficiency at low superficial gas velocity gave unsatisfactory separation of merely 40% of rice husks. At higher superficial gas velocity, separation efficiency of rice husks as high as 93% was achieved. In addition, higher distributor inclination angle gave slightly improved separation efficiency. The drying kinetics showed that the residence time that is required to reduce the moisture content of rough rice to 18% (intermediate storage moisture content for second stage drying) is 3 minutes whereas the residence time that is required to reduce the moisture content to 13% (desirable final moisture content) is approximately 10 minutes regardless of the effect of kernel cracking. It was also found that higher drying temperatures gave higher drying rate. A conceptual design has been developed based on the results obtained in the studies. In order to maximize the heat utilization and to carry out two processes viz. dedusting and drying in one unit processor, it is suggested that drying – dedusting can be carried out in a multistage mode where drying is taken place at each stage while dedusting is taking place at the upper stage. This concept can be applied to a packed bed or a fluidized bed unit processor.


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