Research On High Concentration Brine Disposal Technology Based On Mesoscopic Spray Evaporation System

With the blossom of global economy, brine disposal with low energy consumption and reutilization is still a hot issue both in industry and desalination field. Brine mesoscopic spray evaporation technology not only has advantages of energy saving and low carbon dioxide release, but is useful to reutilization of high concentration brine. In addition, the technology integrated with membrane process can enhance the brine disposal efficiency.In this paper, a mesoscopic spraying evaporation system is applied to high concentration brine disposal. A running test is conducted and the desalting mechanism, performance simulation as well as economic analysis of this system have been investigated. The main conclusions are as follows:1.The mesoscopic spraying evaporation system consists of five components, including heat supply system, evaporation system, feed supply system, gas system, and recovery system. A discrete phase model in brine mesoscopic spraying evaporation system was developed.The brine droplet evaporation and diffusion process in heating airflow was simulated by Fluent. This model was verified by comparing simulation temperature with the experimental. Several operating parameters, including compressed air pressure, temperature and flux of heating air, feed rate of brine, were investigated to examine their effects on the evaporation(E) and the evaporation rate(R). It must be stressed out that the simulation results showed a great agreement with the measured ones.Therefore, the model is reasonable.2. Experiments were conducted to enhance spray evaporation efficiency. It was found that the optimum working condition iscompressed air pressure at 0.3MPa, heating air flux at 65 m3/h, temperature at 270℃, feed flux at 11 L/h. A test system was built to investigate the mesoscopic spray performance of the two-fluid nozzle. It was found that the optimum working condition is liquid pressure at 0.1 MPa and gas pressure at 0.2 MPa. In addition, the higher liquid temperature is, the smaller brine average diameter is; brine s alinity has little effect on atomization.3. A set of parabolic trough solar collector device was designed, and the performance of it was investigated. The parabolic relationship between air flux and solar collector efficiency was fitted, and it was proved to be feasible by error analysis.4. A mesoscopic spraying evaporation system integrated with a set of parabolic trough solar collector device was built, in which brine can be condensed from 146.79 g/L to 351.88 g/L under the optimum operating condition. Compared with system powered by electric energy, the power consumption in mesoscopic spray evaporation system with solar collector was saved approximately 70% under the same condition that both two systems operated for eight hours in one day. In addition, the system was optimized through Colebrook White equation, which revealed that the power consumption could be further reduced.