7/23/2019 BAR Technical Poster Model 2

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Fluidized bed drying system offers better solution whendrying 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 systemthat entirely uses fluidized bed dryers for both first stageand second stage drying.

Thus, in 2013 PHilMech developed a laboratory-scalemodel with 5 kg/batch capacity (Pontawe, et.al., 2013).Therefore, the established technical parameters needs tovalidate for larger Fluidized Bed Dryer capacity.

The developed laboratory-scale fluidized bed dryer

To evaluate a pilot-scale (500 kg/h grain flow rate) fullyautomated fluidized bed dryer for drying high moisturepaddy.

To validate the technical operating conditions for fulldrying of high moisture paddy.

To evaluate the grain quality and energy consumptionof the developed pilot-scale model fluidized bed dryersystem.

To determine the drying cost per kg of wet paddy driedto fluidized bed dryer.

Material flow diagram of the pilot-scale model during dryingexperiments

1. Loading Bin2. Venturi-typeConveyor3-4 Drying Chamber5-6 Tempering Bin7. Screw Conveyor

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 min. temperingCapacity: 500 kg/hrDrying time: 2.5 hoursEnergy requirement: 2.84 MJ/kgMilled products passed the PAES limits for HRY recovery.

Color, aroma, taste and mouth-feel have no significant difference comparedto air dried sample.

Drying Cost : Php 0.63/kg

Drying could be

done in severalways

Sun drying is the cheapestmethod, but it is notfeasible during rainyseasons.

Mechanicaldryers likeflatbed is laborintensive

Recirculating batch-type is not ideal forhandling high moisturepaddy.

Figure 1. The automated pilot-scale fluidizedbed dryer

Particulars Parameters

Drying temperature (oC) 70

Airflow rate (m3/s) 1.47 (4.9 m/s)

Static pressure (inch H2O) 6

Grain depth (cm) 10.16

Fluidization time (minute) 2

Ambient tempering (minute) 30Forced air tempering (minute) 30

Table 2. Technical parameters established

Table 1. Mean scores on the color, aroma,taste and mouth-feel of paddy dried

Attributes Product Mean Mean Std. Error

Over-all

liking

 A 6.7292a  0.19465

B 6.9167a  0.18792

Color  A 6.9800a  0.19057

B 7.3400a  0.17982

Aroma  A 6.5510a  0.17990

B 6.2449a  0.28050

Taste  A 6.9800a  0.19270

B 6.8800a  0.24014

Mouth-

Feel

 A 6.2245a  0.26609

B 6.4286ab  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   C

   (   %   w  e   t   b  a  s   i  s   )

Drying Time (min)

Figure 2. Moisture reduction of paddy dried at70

˚

and 2 min fluidization time with 30.95% (wetbasis) initial MC

00.080.160.240.320.4

0.480.560.640.720.8

0.880.96

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 differentdrying 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 4. Normalized MC of paddy dried at 70 ˚Ctemperature

2.2

2.7

3.2

3.7

4.2

4.7

5.2

5.7

65 75 85 95 105   S  p  e  c   i   f   i  c   H  e  a   t   E  n  e  r  g  y

   R  e  q  u   i  r  e  m  e  n   t   (   M   J   /   k  g   )

Drying temperature, oC

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 65 70 75 80 85 90 95 100 105

   H   R   Y   R

Drying temperature, oC

2 minutes fluidization

3 minutes fluidization

Figure 5. Specific heat energy requirement (MJ/kg)at different drying temperature

Figure 6. Head rice yield reduction ratio ofsamples dried in relation to the diff. dryingtemperatures (HRYR with the same script is notsignificantly different at a=0.05)

Reagan J. Pontawe1, Nestor T. Asuncion1, Roselyn B. Villacorte2 , Romualdo C. Martinez3 and Rex L. Bingabing4

1Science Research Specialist, 2Science Research Analyst, 3Chief Science Research Specialist, 4 Director IV

Particulars Value

Fixed Cost (Php/batch) 430.52

- R & M 133.33

- Depreciation cost 215.00

- Registration expenses 82.19

Variable Cost (Php/batch) 3,329.48

- Salary and wages 500.00

- Fuel cost 2,799.50

- Power cost 214.98

Total Operating Cost 3,760.00

Drying cost (Php/kg) 0.63a

Drying cost (Php/kg) 0.31b

Table 3. Drying cost per kg of dried paddy

50 kg = 1 baga Based on full capacity 500kg/hr for 12hr/batchb Potential drying cost using biomass furnace as heat source