Cross-Technology Scheme Options to Reduce Greenhouse Gas Emissions in a Steel Industry

Abstract

Steel production heavily depends on carbon bearing compounds for process and as well as for energy requirements. Due to the inherent use of coal in an integrated steel making process as a source of energy and as a reductant, total decarbonization of currently operating plants is extremely difficult. Most of the carbon used in steel making process is emitted to the atmosphere in the form of CO2. Obviously, the steel industry is emission intensive, contributing 7% of global CO2 emissions. Reducing greenhouse gas emissions from steelmaking is necessary to meet the challenges of climate change. A portfolio of technologies and approaches will be needed to address the decarbonisation challenge, while supporting steel industry competitiveness. This paper explores the technologies and strategies to reduce CO2 emissions from an integrated steel plant. Improving energy efficiency of steel making process is the first step in emission reduction. However, it is limited by thermodynamic constraints. Based on the current state of development, Carbon Capture and Utilisation (CCUS), Carbon Capture and Storage (CCS) are found to be the suitable technologies from the breakthrough technologies identified by World Steel Association to reduce CO2 emissions from iron and steel making process. It has been estimated that CCS can reduce the CO2 emissions from an integrated steel plant potentially by 40%. Suitability of both chemical and biochemical technologies to utilise steel plant off gases for producing value added chemicals are investigated. Combination of CCUS and CCS may be an attractive option in terms of comprehensive emission reduction. Availability of hydrogen will improve utilisation of steel plant off gases. The economic feasibility of CO2 re-use options relies on the efficiency of carbon conversion, the value of the intended products and the availability of cheap renewable power and in some cases, hydrogen.