Research progresses on evaporation characteristics of desulfurization wastewater droplets in high-temperature flue gas

Utilization of hot flue gas for desulfurization wastewater treatment has the advantage of simple process and high efficiency. However, the imprecision of mechanisms of evaporation commonly exists in evaporation treatment technology. In this paper, evaporation characteristics of desulfurization wastewater droplets (group) and existing problems were summarized. Evaporation behaviors of desulfurization wastewater droplets were firstly introduced, elucidating discrepancy between pure instances and wastewater during the evaporation process was owing to the vapor pressure depression of saline solution and precipitation of the salt. Spray scale experimental studies on evaporation treatment technology for desulfurization wastewater by flue gas were summarized. Important factors including gas temperature, velocity and wastewater characteristics were concluded. To inquire about the essential relevance between operation parameters and different characteristics of wastewater, numerical simulations and drying kinetic models were discussed. Additionally, single droplet drying (SDD) technologies and their applications were reviewed, which helps obtain specific drying history of wastewater droplet and construct drying kinetics of desulfurization wastewater. At last, CFD coupled with the reaction engineering approach (REA) was expected to delineate the evaporation process of desulfurization wastewater well. It is advisable to combine the information of macroscopic spray evaporation and the results of single droplet drying, which may reveal the internal mechanism of evaporation of desulphurization wastewater. © 2021, Chemical Industry Press Co., Ltd. All right reserved.