Life Cycle Assessment of Oxygen and Nitrogen Production in Iron and Steel Industry and Its Regional Comparison
摘要
The basic oxygen process, which involves blowing oxygen into molten iron to reduce its carbon content from 4 to < 0.5%, is used to make more than half of the steel used worldwide. The present study delves into a detailed environmental implication of commercially produced oxygen and nitrogen in oxygen unit within a steel plant. The focus is on cryogenic air separation, a widely adopted method for industrial oxygen generation. The primary data is collected from the iron and steel industry located in eastern India. The life cycle assessment investigated the fact that electricity consumption has a considerable contribution to the majority of environmental impacts. Alone, electricity highly adds to the global warming potential (825 kg CO2 eq.), marine aquatic ecotoxicity (1.18E + 6 kg DCB eq.) and abiotic depletion potential (fossil) (8.36E + 3 MJ). The water consumption in cryogenic air separation has a minimum impact. The overall impact of oxygen production per ton of crude steel is also reported. The production impacts are also compared with the Netherlands and Germany database (GaBi-8.5.0.79 version). The results revealed a significantly higher environmental impact for the Indian region compared to the Netherlands and Germany. India's reliance on non-renewable energy sources, mainly coal for electricity, is an important reason behind its consistently higher impact across all measured impact categories. This contrasts with countries like the Netherlands and Germany, which utilise more renewable energy sources.