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7/21/2019 Fluidized Bed Dryer Technical Poster http://slidepdf.com/reader/full/fluidized-bed-dryer-technical-poster 1/6 Fluidized bed drying system offers better solution when drying high moisture paddy. The grains are semi-suspended in high air flow and experience vigorous mixing. To this date, there is no commercial paddy drying system that entirely uses fluidized bed dryers for both first stage and second stage drying. Thus, in 2013 PHilMech developed a laboratory-scale model with 5 kg/batch capacity (Pontawe, et.al., 2013). Therefore, the established technical parameters needs to alidate for larger Fluidized Bed Dryer capacity. The developed laboratory-scale fluidized bed dryer To develop a pilot-scale model fluidized bed dryer for high moisture paddy with full-automatic control system. Specific Objectives: To evaluate a pilot-scale (500 kg/h grain flow rate) fully automated fluidized bed dryer for drying high moisture paddy. To validate the technical operating conditions for full drying of high moisture paddy. To evaluate the grain quality and energy consumption of the developed pilot-scale model fluidized bed dryer system. Material flow diagram of the pilot-scale model during drying experiments 1. Loading Bin 2. Venturi-type Conveyor 3-4 Drying Chamber 5-6 Tempering Bin 7. Screw Conveyor Complete drying of high moisture paddy can be attained using fluidized bed drying system with the following technical parameters: 70°C drying temperature 2 minutes fluidization time 10.16 cm grain depth 6 in H2O static pressure 4.9 m/s superficial air velocity 60 minutes tempering (ambient air & forced air) The developed fluidized bed dryer system offers low energy requirement (2.84 MJ/kg with substantial reduction on the drying time (82%). Milled products dried using the technical parameters passed the PAES limits for HRY recovery. Major parameters that influenced consumer’s preferences in buying milled rice like color, aroma, taste and mouth-feel have no significant differences between the fluidized bed and air dried sample. Drying could be done in several ways Sun drying is the cheapest method, but it is not feasible during rainy seasons. Mechanical dryers like flatbed is labor intensive Recirculating batch-type is not ideal for handling high moisture paddy. The developed automated pilot-scale model fluidized bed dryer Particulars Parameters Drying temperature ( o C) 70 Airflow rate (m 3 /s) 1.47 (4.9 m/s) Static pressure (inch H 2 O) 6 Grain depth (cm) 10.16 Fluidization time (minute) 2 Ambient tempering (minute) 30 Forced air tempering (minute) 30 Table 1. Technical parameters established Table 2. Mean scores on the color, aroma, taste and mouth-feel of paddy dried Attributes Product Mean Mean Std. Error Over-all liking A 6.7292 a 0.19465 B 6.9167 a 0.18792 Color A 6.9800 a 0.19057 B 7.3400 a 0.17982 Aroma A 6.5510 a 0.17990 B 6.2449 a 0.28050 Taste A 6.9800 a 0.19270 B 6.8800 a 0.24014 Mouth- Feel A 6.2245 a 0.26609 B 6.4286 ab 0.24046 10.00 14.00 18.00 22.00 26.00 30.00 34.00 0 20 40 60 80 100 120 140 M o i s t u r e c o n t e n t ( % w e t b a s i s ) Drying Time (min) Figure 1. Moisture reduction of paddy dried at 70˚C and 2 min fluidization time with 30.95% (wet basis) initial MC 0 0.08 0.16 0.24 0.32 0.4 0.48 0.56 0.64 0.72 0.8 0.88 0.96 0 20 40 60 80 100 120 140 ( M - M e ) / ( M o - M e ) Drying time (min) 70 80 90 100 Figure 3. Normalized MC of paddy dried at different drying temperatures with 2 min. fluidization 0 0.2 0.4 0.6 0.8 1 1.2 0 20 40 60 80 100 120 140 ( M - M e ) / ( M o - M e ) Drying time (min) 2 min fluidization 3 min fluidization Figure 2. Normalized MC of paddy dried at 70 ˚C temperature 2.2 2.7 3.2 3.7 4.2 4.7 5.2 5.7 65 70 75 80 85 90 95 100 105 S p e c i f i c H e a t E n e r g y C o n s u m p t i o n ( M J / k g ) Drying temperature, o C 25-30% (w.b.) IMC 31-35% (w.b.) IMC a b a b 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 60 70 80 90 100 110 H R Y R Drying temperature, o C 2 minutes fluidization 3 minutes fluidization Figure 4. Specific heat energy requirement (MJ/kg) of paddy dried at different drying temperature with 2 min. fluidization time and 60 min. tempering period Figure 5. Head rice yield reduction ratio of samples dried in relation to the different drying temperatures (HRYR with the same script is not significantly different at a=0.05) Engr. Reagan J. Pontawe 1 , Engr. Nestor T. Asuncion 1 , Engr. Roselyn B. Villacorte 2 and Dr. Romualdo C. Martinez 3 1 Science Research Specialist, 2 Science Research Analyst, 3 Chief Science Research Specialist
