Performance analysis of combined humidified gas turbine power generation and multi-effect thermal vapor compression desalination systems Part 2: The evaporative gas turbine based system and some discussions

This is Part 2 of the paper “Performance analysis of combined humidified gas turbine power generation and multieffect thermal vapor compression desalination systems — Part 1: The desalination unit and its combination with a steam-injected gas turbine power system”. A combined power and water system based on the evaporative gas turbine (EvGT) is studied, and major features such as the fuel saving, power-to-water ratio, energy and exergy utilization, and approaches to performance improvement, are presented and discussed in comparison with STIGand EvGTbased systems, to further reveal the characteristics of these two types of combined systems. Some of the main results of the paper are: the fuel consumption of water production in STIG-based combined system is, based on referencecycle method, about 45% of a water-only unit, and that in an EvGT-based system, it is 31–54%; compared with the individual power-only and water-only units, the fuel savings of the two combined systems are 12%–28% and 10%–21%, respectively; a water production gain of more than 15% can be obtained by using a direct-contact gassaline water heat exchanger to recover the stack heat; and the combined system are more flexible in its power-towater ratio than currently used dual-purpose systems. Further studies on aspects such as operation, hardware cost, control complexity, and environmental impact, are needed to determine which configuration is more favorable in practice.