Characteristic of Vertical Mixed Flow Dryer in Coffee Bean Drying Process

Abstract

This paper proposes a new type of vertical mixed flow dryer and evaluates the characteristic of the dryer for coffee bean drying. The specific design of vertical mixed flow dryer was in the drying chamber that equipped with a perforated-sloped tray to retard grain flow while drying. The dryer characteristic was presented in a form of humidity and temperature behaviour during the drying process. This characteristic could be a database to get coffee with standard moisture content (MC). Parameter stated were air temperature (°C), humidity (kg/kg dry air), coffee bean mass flow rate (kg/s), and air velocity (m/s). For air velocity of 2 m/s, this dryer was able to dry coffee bean from 52% initial MC to final 14% MC for 11,5 hours.