Macroeconomics

Engineering

Partial equilibrium

Ecology

Biology

Microeconomics

Economics

Supercritical fluid

Coal

Waste management

Environmental engineering

Organic chemistry

Life-cycle assessment

Pulverized coal-fired boiler

Process engineering

Environmental science

Environmental impact assessment

Chemistry

Power station

Boiler (water heating)

General equilibrium theory

Production (economics)

Boiler feedwater

Electrical engineering

Journal of Cleaner Production

With ever increasing share of renewable energy sources in the electricity mix, pulverized coal-fired power plants (PCPP) have to participate in peak load regulations frequently and thus, they regularly operate under partial loads. The energy efficiency and eco-efficiency are both significantly affected by such operating patterns. Therefore, the present work aims to establish an overall concept for the estimation of environmental impacts from PCPP under nominal and partial loads with combined thermodynamic analysis and life cycle assessment (LCA) methodology. A 1000 MW supercritical PCPP was modeled using commercial simulation software (GSE for thermodynamic simulation and SimaPro for LCA analysis). Results indicated that global warming was the predominant environmental impact of PCPP, while ozone formation, acidification and eutrophication were also serious concerns attributed to NO x emissions in electricity generation process. The mechanisms of formation, migration and removal of different kinds of pollutant emissions significantly influenced the LCA results. Particularly, the total environmental impact potential considerably increased by approximately 90% under partial/low loads due to reductions in the plant thermal efficiency and NO x removal efficiency. A novel partial load No.0 feedwater preheating system driven by steam ejector was thus proposed for NO x reduction improvement. Operation optimization was carried out based on the guidelines of the LCA framework. It was found that the total environmental impact could be effectively reduced by up to 27.3%. Therefore, the implementation of the No.0 feedwater pre-heater was favorable for environmental performance improvement under partial/low loads. • A framework of combined LCA-thermodynamic modeling of PCPP was developed. • Distribution of environmental impacts of PCPP under partial loads was demonstrated. • Environmental impact of PCPP under low loads considerably increased. • Partial load No.0 feedwater preheater driven by steam ejector was proposed. • Low load environmental impact was reduced by increasing feedwater temperature rise.

Thermodynamic analysis and life cycle assessment of supercritical pulverized coal-fired power plant integrated with No.0 feedwater pre-heater under partial loads