两级叠置式加湿除湿海水淡化装置性能研究

The humidification-dehumidification seawater desalination technology shows significant potential as a method for freshwater production. Nevertheless, challenges such as heat and mass imbalances between the humidification and dehumidification processes caused by uneven spraying result in a low freshwater production rate per volume. In this regard, this paper proposes a compact two-stage humidification-dehumidification (HDH) desalination system. The device contains two humidifiers and a dehumidifier, wherein the dehumidifier is stacked between the vertically placed humidifiers. Its freshwater yield performance was evaluated through an electric heating steady-state experiment, varying the feed seawater mass flow rate, feed seawater temperature, and preheating conditions. The results show that the water production of the device increases with the increase of feed seawater flow rate and temperature. Specifically, an increase in feed seawater mass flow rate from 0.45 t/h to 0.96 t/h resulted in a corresponding increase in freshwater yield from 18.7 kg/h to 27.1 kg/h. At a feed seawater temperature of 85℃, the device achieves a freshwater yield of 33.7 kg/h with a gained output ratio (GOR) of 0.9. In addition,preheating the device can potentially enhance the freshwater yield by up to 6.8%. The maximum per unit volume freshwater yield of the device is 33.7 kg/(m³·h), which is obviously higher than traditional two-stage HDH device.