Research on Two-stage Humidification-dehumidification Heat Pump Desalination System

Abstract

For the humidification-dehumidification desalination unit to perform more efficiently, a two-stage humidification-dehumidification heat pump desalination system was proposed. So as to improve the heat and mass transfer effect between seawater and moist air, the two-stage humidifier was employed to recover the waste heat of seawater discharged from the first stage humidifier. The models of a one-stage and two-stage humidification heat pump seawater desalination system were built using Aspen Plus simulation software. Multi-condition simulation studies were carried out for different inlet seawater temperatures, liquid-gas mass ratios, and refrigerant flow rates of the heat pump. According to the comparative examination of the simulation’s outcomes, it is concluded that: with the increase in inlet seawater temperature and liquid-gas flow ratio, the two-stage humidifier system’s recovery rate and gain output ratio are superior to those of the first-stage humidifier system, and the inlet seawater temperature and circulating airflow needed for the two-stage humidifier system to perform at its best are less demanding than those for the first-stage humidifier system., indicating that the two-stage humidifier dehumidification desalination technology of the heat pump has great performance improvement and a broad application prospect.