Investigation on Heat and Mass Transfer in Spray Drying Process

Electrochemical properties of Lithium Ferrous Phosphate (LFP or LiFePO4) make it a promising cathode material for lithium-ion batteries in electric vehicle applications. Spray drying is often used for manufacture of LFP cathode powder as the method results in particles of uniform size and with favorable structure. Analyzing the heat and mass transfer characteristics during a spray drying process through experiments is expensive and involves tedious measurements and methods. This paper presents a computational fluid dynamics study of heat and mass transfer characteristics of spray drying process. The technique uses a 2D axisymmetric model that mimics a drying chamber of 0.25 m in diameter and 0.6 m in height to study the spray drying behavior. The working pressure and the flow rate required as input for the computational domain were obtained experimentally with the use of distilled water spray through a full cone nozzle. The computational model is validated with experimental data on water spray and extended for the LFP precursor. The variation of the mass fractions of the multi-component substance (LFP and water) and the influence of the pumping pressure and temperature of the carrier gas are discussed. Increased pumping pressure allows fine atomization and consequently reduces the drying time. The analysis enables better understanding of the spray drying mechanism and is helpful during spray dryer design.