EXERGOENVIRONMENTAL EVALUATION FOR A COAL-FIRED POWER PLANT OF NEAR-ZERO AIR POLLUTANT EMISSION

Owing to the growing environmental concerns, super-critical and ultra-supercritical coal-fired power plants dominate the electricity generation with the demand of near-zero air pollutant emission in China. Therefore, it is highly expected to assess the environmental impact and optimize the design at global and local levels. Exergoenvironmental analysis is a valid approach to investigate the formation of environmental impacts (EIs) associated with energy conversion systems at the component level. It generates information crucial for designing systems with a lower overall environmental impact, based on life cycle assessment (LCA) and exergy analysis. A 600 MW supercritical coal-fired system with and without dust, SO2 and NOx mitigation controls was analyzed. Heat transfer in the boiler, condenser(CND), low pressure cylinder(LP), air preheater(APH) show high potential to decrease the environmental impact due to high exergy destructions. The deaerator (DEA), induced draft fan(IDF), forced draft fan(FDF) should be focussed on construction design and manufacturing optimization. Purification units reveal high benefit for reducing EI produced by coal combustion, but there is a large space for the EI saving for it. The specific EI of electricity in China is much greater than European.