Experimental Investigation of the Performance of a Spouted Bed Dryer for Biomass: Drying Kinetics and Energy Evaluation

Abstract

Drying is an essential pre-treatment step that plays a critical role in the energy balance of biomass power plants. This has motivated the search by cost-effective drying technologies. Within this context, the present work aims to investigate the application of a spouted bed dryer with inert solids for drying sugarcane bagasse, the most important biomass used for generating energy in Brazil. Effects of the biomass volume fraction, inlet air temperature and spouting gas flow rate on the drying time and thermal efficiency of the equipment were examined. Results show that drying time decreases by decreasing the biomass fraction and by increasing air temperature. Highest values of biomass percentage and air temperature allied to the lowest velocity of the spouting air greatly improve the efficiency of the biomass drying. Based on a balance between the energy that the product is capable of suppling and the total energy consumed by the dryer the optimum operating conditions recommended for making feasible the use of the bagasse dehydrated in spouted bed for energy purposes are: air temperature of 67°C, biomass volume fraction of 0.6 and air flow rate equal to the minimum stable spouting condition.