CFD modeling and analysis of brine spray evaporation system

摘要

A spraying evaporation system applied to brine disposal is reported, which is mainly used for disposing the brine with concentration more than 100,000mg/L. A computational fluid dynamics (CFD) simulation has been carried out to study the brine droplet evaporation and diffusion process in high temperature air flow. A discrete-phase model in spraying evaporation system is developed and a simulation experiment based on the gas-liquid phrase coupling with hydromechanics theory is conducted, respectively. In the present study, this model is further verified by comparing simulated temperature with experimental temperature under the condition of feed rate at 11, 13, and 15L/h, respectively, hot air flux at 78m(3)/h, temperature at 260 degrees C, and compressed air pressure at 0.2MPa. It should be pointed out that the CFD results are in reasonable agreement with experimentally measured ones. A thorough analysis of the heat- and mass-transfer in controlling steps is conducted based on this model to determine the impacts of key parameters that could contribute to an enhanced spray evaporation system, and finally find out the optimized operating condition. Several operating parameters, including air pressure given by air compressor, temperature and flux of hot air, and feed rate of brine are investigated to examine their effects on the evaporation (E) and the evaporation rate (R). The results show that the optimized operating condition of spraying system is air pressure at 0.3MPa, hot air temperature at 270 degrees C, hot air flux at 64m(3)/h, and brine feed rate at 11L/h.