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.
Keywords FGD wastewater, zero liquid discharge, solar energy utilization, economic analysis