Life Cycle Assessment of a steel component produced from electric arc furnace

Abstract

This study aims to assess the environmental impact of manufacturing ready-to-use low-alloy steel pup joints used in drilling in the oil and gas sector. The company uses low alloy steel (AISI 4145H) produced from recycled scrap via the electric arc furnace (EAF) route. The Life Cycle Assessment (LCA) is used for the environmental analysis. Foreground data at plant sites are collected from the CNC machining company in Norway and the production of steel in central Europe. Background data, such as the transportation and electricity origin, are taken from Ecoinvent 3.8. database and from literature. The system boundary of the project is gate-to-gate (from scrap to the pup joint production) and included unit processes are EAF steel production, hot rolling, quenching and tempering, CNC drilling and CNC turning. LCA results show a high contribution to the environmental impacts due to non-renewable electricity sources and materials transport among different companies in central Europe, with the final destination in Norway. Changing the source of electricity for the entire production line would generate environmental benefits. The Global Warming Potential calculated for the scenario of producing the pup joint entirely in Norway, where the electricity grid is based on hydropower (>90 %), was 215CO2eq versus 466 CO2eq for the current production line, mostly conducted in Europe with fossil fuel as main energy source. An ideal scenario can be suggested, namely the creation of an industrial park in Norway, in order to remove the transport and use renewable energy. But, more realistically, the potential limitations of the proposed solution (e. g., infrastructure costs, production capacity in Norway) should be discussed to provide a balanced view of its feasibility.