Proposal and analysis of a dual-purpose system integrating a chemically recuperated gas turbine cycle with thermal seawater desalination

A novel cogeneration system is proposed for power generation and seawater desalination. It combines the CRGT (chemically recuperated gas turbine) with the MED-TVC (multi-effect thermal vapor compression desalination) system. The CRGT contains a MSR (methane-steam reformer). The produced syngas includes plenty of steam and hydrogen, so theworkingmedium flow increases and NOx emissions can achieve 1 ppm low.However, thewaterconsumption is large,∼23 t/dwaterperMWpoweroutput. To solve thisproblemand produce water for sale, MED-TVC is introduced, driven by exhaust heat. Such a dual-purpose plant was analyzed to investigate its performance and parameter selection, and compared with four conventional cogeneration systemswith the samemethane input. Somemain results are following: In the base case of the CRGTwithaTITof1308 Canda compression ratioof15, theMED-TVCwith9effects, the specificworkoutput, performance ratio and CRGT-consumed water ratio are 491.5 kJ/kg, 11.3 and 18.2%, respectively. Compared with the backpressure ST (steam turbine)/CC (combined cycle) plus MED/MSF (multistage flash), the CRGTþMEDhasbetter thermalperformance, lowerproduct costand shorterpaybackperiod,which indicates the CRGT þ MED dual-purpose system is a feasible and attractive choice for power and water cogeneration. 2010 Elsevier Ltd. All rights reserved.