Performance analysis of electroplating wastewater treatment system combining air compression expansion cycle with spray drying tower

Using traditional thermal evaporation to treat electroplating wastewater still consumes a lot of energy and it is impossible to completely separate salt and water. In order to separate salt and water with a high efficiency, a novel system combining air compression expansion cycle and spray drying tower is proposed for electroplating wastewater treatment. It is a good attempt to use the air compression expansion cycle as a component to provide service of heat and humidity treatment for the tower, and the feasibility of this combination is explored. In the paper, effects of compressor inlet parameters and pressure ratio on system performance are investigated, and the required pressure ratio is analyzed with different tower inlet temperatures. Meanwhile, the system efficiency ratio is compared with other systems. It is revealed that adjusting air compression expansion cycle to match spray drying tower is beneficial for the operation of the tower. The inlet air temperature of tower can realize to 159.6 °C, and its humidity is less than 6.37 g·kg−1. What’s more, increasing of inlet air humidity in compressor is proved advantageous for promoting system performance, and selecting appropriate inlet air temperature and pressure ratio of compressor can meet the demand of the spray drying tower and result in the improvement of system performance. Moreover, as the temperature difference between inlet of compressor and tower is increased, the pressure ratio required of system is increased. In addition, the system efficiency ratio can achieve 7.13 kg·kWh−1, and it is energy-efficient comparing with other systems.