Thermodynamic and Techno-economic Analysis of Solar-Steam Hybrid Driven Flue Gas Desulfurization Wastewater Zero Liquid Discharge System

Zero liquid discharge (ZLD) of flue gas desulfurization (FGD) wastewater from coal-fired power plants (CFPPs) provides an approach to comply with the increasingly stringent environmental regulations. However, traditional ZLD systems are commonly subject to high operating cost. A solar-auxiliary steam hybrid driven ZLD system is thereby proposed in the present work. Thermodynamic and economic analysis models were established. A case study in a 600 MW CFPP was carried out under the meteorological conditions of a typical city in China. It is found that the lowest levelized cost of wastewater treatment (LCOW) obtained was approximately 10.1 $/t, and the cost could be reduced by marginally 8.0% by utilizing hybrid heat sources. A parametric study was further performed to investigate the impact of key variables on the LCOW, and indicated that auxiliary steam cost had the largest impact.