Simulation of desulphurization wastewater evaporation through flue gas

As an advanced treatment of desulphurization wastewater, spray evaporation technology has received significant attention and broad research interests recently. However, the results of previous studies were based on the simplification that droplets of desulphurization wastewater were regarded as droplets of pure water. To effectively reveal the evaporation mechanism of desulphurization wastewater, the evaporation model of droplets with different salt contents was used. The effects of parameters such as nozzle arrangement, droplet diameter, temperature of flue gas and salt content were obtained by numerical simulation. And the operation situations of evaporation equipment under different working conditions were analyzed. Numerical results show that the symmetrical arrangement of nozzles should be adopted since there is no scaling or corrosion in flue. The evaporation time of droplets could be shortened by adopting uniform diameter distribution. Droplets with small diameter under high flue gas temperature require less time and shorter distance for complete evaporation. The optimum diameter and temperature of flue gas are found to be 54 μm and 403 K, respectively. The increase of salt content of droplets could lead to the increase of mean distance and time which are needed for complete evaporation of droplets. And the droplets cannot completely evaporate under 75% THA (turbine heat acceptance) in which the evaporation equipment should not be turned on.