COMPARATIVE STUDY ON THE DRYING OF OIL PALM SOLID WASTE USING CONVENTIONAL AND MICROWAVE METHODS

The purpose of drying is to reduce material humidity or water content. Several techniques can be used in the process, including conventional and microwave drying. Drying of oil palm solid waste aims to improve its physical properties. The study used a 10 g sample for each drying test. The drying process was performed on six variations of the drying temperature, i.e., 40, 45, 50, 55, 60, and 65 ℃. The temperatures used for heating started from ambient temperature to the predetermined drying temperatures, then it was held for 90 minutes. The measurement of the mass was performed every 20 seconds. Based on the result, it can be concluded that drying using a microwave oven gives higher effectiveness compared to drying using a conventional oven. The high drying temperature affects not only the drying rate constant throughout a constant time but also the drying rate constant during the falling rate period. For both methods, the drying rate has been found to be linearly proportional to the drying temperature. The increasing drying temperature will decrease energy intensity. There is no significant impact in the pore structure of drying products using microwave and conventional ovens at 65 ℃.