Performance Evaluation of drying Ccharacteristics in conical bubbling fluidized bed dryer

Abstract

Paddy drying is an important task which is vital to the quality and storability of rice. Hence, evaluation of the drying process has to be performed for achieving a good quality of dried paddy in shorter duration. In this present work, performance evaluation of the drying process of paddy was experimentally investigated in two conical bubbling fluidized bed dryers with cone angles of 5° and 10° and results were compared with a conventional fluidized bed dryer having cone angle 0°. The experiments were conducted at three different superficial air velocities of 1.1, 1.6 and 2.1 m/s with bed inventories between 1 and 3 kg. Three different inlet air temperatures of 55, 60 and 65 °C were maintained for the evaluation of the drying process. Both hydrodynamic behaviour and drying characteristics have been investigated at these operating conditions. It has been evident from the experimental investigations that the conical fluidized bed dryer with 10° cone angle shows better performance than the other two dryers. The quality of the dried product has been tested for three different drying times and results were found to be in good agreement with the previously published literature. The milling quality was also tested for conical dryer and the use of a conical dryer recovered 77% of the milling rice.