Abstract:
Parboiling is a hydro-thermal treatment given to the paddy before milling. The
popular method of drying parboiled paddy is sun drying. Under tropical climatic
conditions, high rain fall is seriously affected on sun drying. Therefore further
development is necessary to improve the mechanical drying systems. In this
research, a study on small scale dryer for parboiled paddy which was designed and
fabricated at Institute of Post Harvest Technology in Anuradhapura was done. The
report describes the dryer performance. Three batches of parboiled paddy were
dried under in small scale dryer with forced hot air at 45°C and one batch under sun
drying. Dried grains were subjected to milling under the unique machine conditions
and it was tested for the qualities of grain. It was found that 12kg/h in fuel
consumption. The lowest drying time (3h 10min) and highest average drying rate
(6.39 %/h) was obtained from 70kg capacity in dryer. The fuel consumption
efficiency, average drying rate, drying efficiency, cracked grain and broken grain
percentage were observed negatively correlated with capacity of the dryer. It was
also observed that there was a correlation between percentage of cracks and
percentage of broken grain during milling. This study concluded that, the better
grain qualities can be obtained through this dryer than sun drying. Although it has
some disadvantages, dryer is very important in rainy season while impossible to
practice sun drying. Further considering the results, it can be concluded that 105kg
is the most appropriate capacity to achieve optimum performances in drying of
parboiled paddy.
