Coffee Beans Drying Using Pilot-Scaled Fluidized Bed Dryer Assisted with Zeolite Adsorbent

Abstract

Drying is a common method applied to agricultural and plantation products to prevent the growth of bacteria and other microorganisms. This research aims to determine the optimum temperature and humidity of the heating air for coffee beans drying in a fluidized bed dryer (FBD) without the addition of adsorbents, to study the effectiveness of zeolite adsorbent as air dehumidifier in order to improve the drying process, and to determine energy consumption in the coffee drying process in an FBD. This research was conducted using 500 grams of Arabica coffee, air temperature variations of 400C, 500C and 600C with an average air velocity of 4.91 m/s. The addition of 1.08 kg of zeolite as an adsorbent was carried out to improve process performance and to reduce the drying time. Coffee bean quality was determined by moisture test using gravimetric method, protein test using Kjeldahl’s method and carbohydrate test using Luff-Schoorl’s method. The results showed that the optimum conditions for drying coffee beans to reduce the moisture content from 28% to 12.45% using an FBD without adsorbent were obtained at a drying air temperature of 500C with a drying time of 3 hours. Coffee bean drying assisted by Zeolite adsorbent was able to reduce the drying time by 11% with the most efficient energy consumption of 76,200 kJ/kg.