Investigation on the rotary atomization evaporation of high-salinity desulfurization wastewater: Performance and products insights

Spray drying of concentrated wastewater epitomizes a harmonious convergence of technological progress, economic viability, and practicality within the realm of zero liquid discharge. Nevertheless, elevated salinity may influence the atomization and evaporation processes, along with the storage and transportation of evaporation products. This study systematically examines the influence of salinity on rotary atomization evaporation performance and evaporation products of wastewater through a series of experimental investigations. The results indicate that, under identical conditions, the overall droplet size of high-salinity wastewater is approximately 20–50% larger compared to conventional wastewater. Salinity significantly influences the atomization particle size (D32), followed by rotation speed, and then influent flow rate. The high-salinity wastewater droplets manifest a multi-bubble growth pattern with earlier shell expansion, where the reduction of free water dominates the overall process dynamics. Despite the diminished evaporation rate, the total evaporation duration shortens with elevating salinity, reducing flue gas consumption by about 10%. With elevated crystalline salt content, high-salinity wastewater evaporation products exhibit pronounced hygroscopicity, manifesting as a viscous powder with suboptimal flowability (FF 3.57) at a 2 wt% moisture content. This study bridges the gap in rotary spray drying technology for high-salinity wastewater treatment, contributing to sustainable water conservation and energy-efficient management. [Display omitted] •Rotary spray drying and product analysis of high-salinity wastewater are conducted.•Salinity elevates atomized particle size by 20–50% compared to ordinary wastewater.•The reduction of free water due to salinity dominates the overall process dynamics.•Due to salinity, products show high hygroscopicity and poor flowability (FF 3.57).