Drying Characteristics of Oil Palm Frond Particles in a Spouted Bed Dryer

Abstract

The large quantity of oil palm fronds is generated by the oil palm plantation. This biomass has been seen as a promising raw material for paper production, biomass fuel and animal feed. Nevertheless, before its utilization, oil palm fronds require proper pre-treatments including drying. The present study aims to study the drying kinetics and characteristics of oil palm frond particles in a spouted bed dryer. In this research, inlet air temperature, air velocity and bed height were varied to obtain the optimal operating conditions for drying. Experimental results indicated that the drying rate is proportional with the inlet air temperature and air velocity, however, it is in reverse relationship with the bed height. The drying kinetic of oil palm frond particles in spouted bed was analyzed via drying curve. The attained drying rate curve shows the drying progressing with an initial drying period and two falling periods. On the other hand, no significant constant rate period could be observed. Combined effects of the parameters which can yield the highest quality product and consuming the least energy were also investigated. It was found that the optimum operating conditions were as follows: hot air temperature at 90oC, air velocity at 1.34 m/s and bed height equal to 10 cm. It is evident that compared to sun drying, a spouted bed drying has resulted in better qualities of dried oil palm frond particles in terms of colour and aroma.