Process analysis of a novel humidification-dehumidification-adsorption (HDHA) desalination method

The desalination through humidification-dehumidification (HDH) presents still a high energy-footprint but shows many unique attributes that pushed a recent revival of R&D for decentralized production of water. In this paper, a novel process scheme consisting of a multiple extraction humidification-dehumidification with vapour adsorption (HDHA) and brine recirculation is analysed. It works with bottom brine temperatures below the coldest heat source and direct recirculation. With respect to the common classification, the process can be considered a closed-air closed-water (CACW) HDH. The study of the degrees of freedom and the mathematical model for the sensitivity analysis are presented. Process simulation showed how to increase the performances above the GOR of 10 with multiple extractions. The basic design of a HDHA producing> 30 m3 day−1 of distilled water, with higher performance (GOR of 7 and a RR of 50%) than the current state-of-the-art, is discussed. Furthermore, the paper reports the process scheme and the mathematical model of the adsorption unit integrated with the HDH, the breakthrough curves and the mass of sorbent needed to carry the novel process. The considerations here presented highlight the key benefits of the new process and bode well for its technological development