加湿除湿脱盐系统的热力学分析及实验研究

基于加湿除湿(HDH)原理，搭建在低温常压下运行的新型脱盐系统，详细介绍系统的结构和工作原理. 在相关假设的基础上对加湿除湿过程进行热力学分析，开展空气循环体积流量、进料体积流量和料液温度等操作参数对系统产水性能影响的实验研究. 实验结果表明，系统产水量随着料液温度和进料体积流量的增加而增大；与预期相反，系统产水量随空气循环体积流量的增加而先增大后减小；当进料体积流量为60 L/h、料液温度为57 °C、空气循环体积流量为180 m³/h时，系统最大产水量和脱盐率分别达到1.7 kg/h、大于99.99%；当料液温度为38 °C时，系统最大造水比和单位体积产水能耗分别为3.8、166 kW·h/m³. 由于具有结构紧凑、模块化设计、操作简单、维护成本低、可以与可再生能源结合等特点，该系统在海水淡化领域颇具竞争力. 上述研究表明，该系统虽然有很大的提升空间，但很有希望应用于分散式小规模淡水生产.

Thermodynamic analysis and experimental study on humidification-dehumidification desalination system

A novel desalination system operated at low temperature and atmospheric pressure was constructed based on the mechanism of the humidification-dehumidification (HDH) process. The configuration and working principle of the system were described. The thermodynamic theories of the HDH process were analyzed based on assumptions. The effect of the operating parameters on the performance of the desalination system was analyzed, including the air circulation flow rate, the feed flow rate and the solution temperature. The experimental results indicated that the water yield of the system increased with the solution temperature and the feed flow rate. The water yield was observed to increase first and then decrease by increasing air circulation rate contrary to expectation. At the feed flow rate of 60 L/h, the feed temperature of 57 °C, and the air circulation rate of 180 m³/h, the maximum yield and salt rejection ratio of the system can reach 1.7 kg/h and more than 99.99%, respectively. When the feed temperature is 38 °C, the maximum gained output ratio and specific thermal energy consumption of the system can reach about 3.8 and 166 kW·h/m³, respectively. It’s a competitive technology for the seawater desalination field due to the advantages of compact structure, modular design, easy operability, low maintenance cost, and great compatibility with renewable energy. Results show that the proposed system has great promise for decentralized small-scale water production applications, although it still has much room to be improved.