Research PaperAdvanced exergoenvironmental evaluation for a coal-fired power plant of near-zero air pollutant emission

- Simulation of a supercritical coal-fired power plant (SCPP) is carried out.
- Detailed advanced exergy and exergoenvironmental analyses are provided.
- Improvement potential and component interactions for environmental impacts are revealed.
- The environmental impacts of purification units are investigated.

Advanced exergy and exergoenvironmental analyses based on life cycle assessment (LCA) are conducted to an SCPP with and without dust, SO2 and NOX mitigation controls. The analyses show that environmental impacts of components are mainly caused by exergy destruction while combustion chamber (COM) still has great potential to reduce pollutant environmental impact reduced by 99.5% by near-zero air pollutant emission standards. Avoidable environmental impact within each component is endogenous other than most regenerative feedwater heaters. COM has the largest environmental impact of exergy destruction but lower avoidable part compared with superheat transfer (SH) including boiling process. Reheat transfer (RH) shows similar avoidable environmental impact but less exergy destruction in contrast with COM. Turbines play well in exergy efficiency and over 50% of environmental impact within intermediate-pressure turbine (IP) can be avoided. Air preheater (APH) displays a higher avoidable environmental impact than condenser (CND) albeit lower exergy destruction. Pumps and fans have small environmental impacts with over 45% can be avoided. Most environmental impact related to pollutant formation is avoidable and endogenous except for wet flue gas desulfurization (WFGD) which imposes a negative environmental impact on other components. The specific environmental impact of electricity generation is higher than European.