Life-cycle assessment of the coal gasification-shaft furnace-electric furnace steel production process

Abstract

China’s steel industry has been phenomenally developed. However, approximately 90% of the crude steel is produced through the blast furnace-basic oxygen furnace (BF-BOF) process with high energy consumption and high pollution. The coal gasification-shaft furnace-electric furnace (CSE) steelmaking technology has recently become a sustainable topic of great concern, due to its environmental and economic benefits. The life cycle assessment (LCA) of the CSE process is conducted to quantify the environmental impact of this new steelmaking process. The GaBi 7.3 software and CML 2001 method are used and the Ecoinvent database is accessed. The life cycle inventory data of the CSE process and BF-BOF process are obtained from a 0.1-Mt/a scale pilot plant and a large-scaled steel plant in China, respectively. The assessment results show that the electric arc furnace (EAF), decarburization, pelletizing and gas heating plants yield the highest contributions to environmental impacts. The environmental impacts of the CSE process and BF-BOF process are 1.83 E−11 and 9.33 E−11, respectively. Compared with the BF-BOF process, the carbon emission and energy consumption of the CSE process can be reduced by 58.1% and 60.6%. Besides, when the ratio of hot metal increases, the environmental performance of the CSE process deteriorates despite the decrease in power consumption. Due to the lower environmental impacts, the CSE process, which is designed to produce steel based on coal, iron ore and scrap instand of hot metal, should be advocated. From the perspective of comprehensive environmental impact, it is necessary to reduce the steel production through the BF-BOF process.