Introduction

The iron and steel industry is one of the largest industrial sources of CO2. Globally, it accounts for about 6% of anthropogenic CO2 emissions (approx. 1.2 Gt CO2/year). Currently, two main processes dominate global steel production:

• the integrated steel mill in which steel is made by reducing iron ore in a blast furnace and subsequent processing in a primary steelmaking plant (BF-BOF Route); and

• the mini-mill in which steel is made by melting scrap steel or scrap substitutes in an electric arc furnace (EAF Route).

In 2011, around 1.5 billion tonnes of crude steel are produced worldwide. Roughly, ~69% of the steel produced are from BF-BOF steelmaking route; and ~29% of the steel produced are from recycled scrap using EAF steelmaking route. Currently, China is responsible for nearly 45% of the steel produced worldwide. Alternative iron and steel making processes based on direct or smelting reduction technologies - such as COREX, FINEX, DRI, Midrex and many others - are also used to produce steel in various sites worldwide. Several of these technologies are commercially proven; however, they only account for a small share of steel produced globally. It is expected that steel production via BF-BOF and EAF routes would still dominate steel production in several decades to come.

To reduce CO2 emissions from steel mills, one of the leading options being considered by iron and steel stakeholders is CO2 capture and storage (CCS). Development of this technology for application in iron and steel production is still on-going (i.e. ULCOS project, World’s Steel CO2 Breakthrough Programme, etc…).

This project, by IEA Greenhouse Gas R&D Programme (IEAGHG) in collaboration with Swerea MEFOS AB was developed with co-funding support from Swedish Energy Agency, SSAB, LKAB and Swerea MEFOS member companies. The project was initiated in January 2010. This was managed by a Steering Committee whose members include representatives from the funding partners. Swerea MEFOS AB led and coordinated this project. Corus Consulting PLC (now TATA Steel Consulting) undertook the cost evaluation and financial modelling; and SINTEF Materials and Chemistry undertook the evaluation of post-combustion capture CO2 modelling.

Key Messages

The global steel industry has made significant investment in reducing CO2 emissions mostly by raising their energy efficiency. However, to achieve a reduction of the direct CO2 emissions per tonne of steel produced from BF-BOF route by greater than 50%, CO2 capture and storage is required.

Development of breakthrough technology such as oxy-blast furnace (OBF) is currently on-going within the steel industry but will require large scale demonstration to validate engineering design and optimisation of the process. This study presented one of the several options that could be employed for a steel mill with OBF and CO2 Capture.

Deployment of post-combustion capture technology, capturing CO2 from various sources of flue gases within the integrated steel mill is technically possible and could be readily retrofitted to an existing steel mill. However, this study has demonstrated that this option could have significant costs implications on steel production which could affect the commercial viability of the steel plants fitted
with CCS.

The steel industry is a globally competitive industry and hence they will be reluctant to introduce cost disadvantages like adding CCS without some global agreement on emissions reduction.