Novel Hybrid Zero Liquid Discharge and Humidification-Dehumidification Desalination System for Waste Heat Recovery from a Gas Engine

Humidification-Dehumidification (HDH) and zero liquid discharge (ZLD) are two methods for water production applications that are of great interest in recent years. In this paper, a new desalination system is proposed which combines the advantages of HDH and ZLD methods to utilize waste heat from a gas engine of 1 MegaWatt electrical capacity. Here, the engine cooling water and the exhaust gas are the low- and hightemperature sources, respectively. The proposed process is presented and the temperatures and flow rates at each point are calculated. Results show that at constant effectiveness factors of humidifier and dehumidifier towers, the total produced water increases with decreasing the ratio of air to seawater flow rates. For the humidifier tower inlet temperature of 90 C , the best output of 1.136 kg/s for 11.34 kg/s seawater intake is achieved. By reducing this temperature to 80 C , the water production increases up to 2.709 kg/s.

Keywords:

Wast Heat Recovery , Humidification Dehumidification , Zero Liquid Discharge , Desalination system