Effects of Drying Air Temperature and Drying Air Velocity On drying Coffee Bean from Biomass Heat using Fluidized Bed Technique

Abstract

               The  purposes  of  this   research  were  to  investigate  the  factors consisted  of  a  temperature   and  Velocity  of  air  flow   affected  Arabica coffee  beans  drying   biomass  combustion  with   fluidization  technique. The fluidized bed dryer,  which was improved from the original heat from the heater  to  use  the  heat  from the  charcoal  stove  as the  heat  source. The  fluidized  bed  dryer  size  of  20 cm diameter and  100 cm height was designed  and constructed  for this The heater and  blower size of 1.25 kW. A cyclone size of  24 cm diameter and 122 cm height was used to  separate the product from air. The galvanized steel pipe size of 4 inch diameter was used as air circulating pipe.  The Arabica coffee  beans  initial  moisture in this   experiment   52.76%   d.b   and   size   of   50  g   was   used   for   each experiment. The drying  temperature conditions were controlled at 55, 70, 85  and  100 ^๐C.  The air velocity conditions in bed were controlled at  5,  6 and 7 m/s. The final moisture of coffee beans was 12% d.b.

                 From the result,  it  was  found that the  drying  temperature  was increased the also drying rate and specific moisture  extraction  rate  trend to  increase.   while  the  specific  energy  consumption   tends  to  decrease. The  highest drying rate was 1.381±0.0061  g_Water/min  that was occurred at 100  ^๐C  dryingtemperature and the 7 m/s air  velocity.  The highest Specific energy consumption,  SEC rate was  6345.25±50 MJ/Kg that was occurred at 100 ^๐C drying temperature and 5 m/s air velocity respectively.