Maltodextrin spray drying in a compact radial multizone dryer – First pilot plant findings

Abstract

A novel compact radial multizone dryer (RMD) has been tested at the pilot scale. In the radial centre of the chamber, hot air and the atomized solution are injected axially and counter current. In the periphery, mild temperature air is injected through multiple short vortex chambers to generate a rotational motion in the chamber and ensure high-G intensified drying and separation of the produced powder and hot drying air. The RMD allows fast initial drying of the injected droplets with hot air in the radial centre and fast evacuation of the initially dried powder to the periphery for final drying with mild temperature air. First, dry and water evaporation tests were carried out to gain insight in the flow pattern and temperature profile in the chamber. Next, a 4.5 min duration spray drying test was carried out using a 40 % maltodextrin model solution at a solution feed rate of 16.1 g/s. The tests demonstrated the working principle and performance of the RMD. Powder recovery and quality, as well as energy efficiency are discussed.