The iron and steel industry is a key sector providing a fundamental material to society. Steel is used in many applications such as buildings, vehicles and large industrial equipment such as power stations and ships. Furthermore, steel is also used in everyday items such as tins for canned food, kitchen appliances, electronics, toys, tools, etc. Globally, each person uses an average of 215kg of steel per year although much of this is used in large scale infrastructure.
Steel is produced from iron ore, a commonly available mineral, in two stages. The first stage is the iron making process where the iron metal is extracted from the iron ore. The second stage is the steel making process where this raw metal is purified to make crude steel. The composition of the steel can be customised to meet specific metal properties, for example corrosion resistance.
The iron making process is the most emissions intensive part for making steel producing between 70 and 80 per cent of the total emissions from producing steel. This involves reacting iron ore with a reducing agent, like coking coal, and produces large volumes of CO2. The most common process used in the world is the blast furnace and this is used to produce around 70 per cent of the worlds steel, although there are other processes that use gas to reduce the iron ore (shown in Figure 1).
Figure 1: Iron and steel making processes (Birat, 2010)
Around 770kg of coking coal are required to produce 1 tonne of steel using this technology. In 2010, the total emissions from steel production were 2,500 million tonnes of CO2 and this is projected to grow by 2050 to a level of 2,800 million tonnes, once the current pledges by governments are taken into account. On average, emissions are around 2t CO2 per tonne of steel produced using the blast furnace route. However, the emissions varies significantly between countries and the Fourth Assessment Report by the IPCC reports the following average emissions:
- Brazil: 1.25 t CO2/t steel
- US: 2.9 t CO2/t steel
- Korea and Mexico: 1.6t CO2/t steel
- China and India: 3.1 to 3.8 t CO2/t steel
Many improvements have been made in the iron and steel sector to increase efficiency and reduce emissions. One of these is the recycling of scrap metal, which avoids the need for the iron making process and is thus able to avoid around 70-80 per cent of the emissions. However, the ongoing demand for steel is high so the processing of iron ore will continue for many more decades to come.
The European Steel Association recently completed a roadmap for a low carbon future for the European steel industry. The current emission levels in Europe are already below the worlds average and this reflects the high use of recycling scrap metal in Europe. For the Roadmap, they completed a number of economic studies that showed that the European steel industry could economically reduce its emissions from the sector by 15 per cent by 2050 over current emissions. Nevertheless, much larger cuts are required to meet global emission reduction pathways. For example, the EU Commission’s Low Carbon Roadmap anticipates an emissions intensity of less than 0.2t CO2/t steel compared to the current levels of 1.3t CO2/t steel. This requires a greater than 80 per cent reduction in emissions and will require both technical and financial breakthroughs in technology. The roadmap indicates that a key technology to achieving larger emission cuts is CCS.
So what is happening in CCS for the Iron and Steel sector?
At present, there are two large-scale integrated projects under development that aim to capture CO2 from iron making. These projects are:
- ULCOS - Blast Furnace: The demonstration project is part of the Europe-wide Ultra-Low CO2-Steel consortium of iron and steel producers. The project aims to capture up to 700,000t CO2 per annum from a blast furnace gas and is located in France.
- Emirates Steel Industry CCS Project: This project aims to capture up to 800,000t CO2 per annum from a Direct Reduction Iron facility. A high purity stream of CO2 is produced from the DRI process and this can be compressed for geological storage. The CO2 is proposed to be used for EOR and full scale operation is anticipated in 2015.
There is also other work in the R&D space including:
- ULCOS: The abovementioned consortium reviews and develops a broad range of new technologies to reduce emissions from iron and steel production. The consortium approach was developed in 2000 and implemented as a major EU program in 2004. To date, ULCOS has assessed 80 different technologies and completed pilot studies on two of these technologies being the top-gas recycle from a blast furnace tested in Sweden and the HIsarna process in the Netherlands. ULCOS was previously reported on by Lindsey Bredin.
- COURSE-50: This is a Japanese national program that aims to firstly develop technologies to reduce emissions from blast furnaces and secondly to develop technologies for CCS that can be applied to blast furnaces.
- POSCO: In Korea, POSCO runs its own program to look at the adaptation of CCS to smelting reduction processes. Separately, they are also completing trials on capturing CO2 from a blast furnace.
- Information is exchanged between all of these programs through the Worldsteel Association’s CO2 Breakthrough Programme.
The Eurofer roadmap indicates that a 60 per cent reduction is the maximum reduction that could be achieved with the deployment of CCS applied to blast furnaces. Hence, further reductions will be required and this includes a portfolio approach where continuing actions will need to be undertaken to decarbonise the electricity sector, consider the use of biomass instead of coking coal and reducing emissions from auxiliary processes such as stoves and reheating furnaces on a site. This includes the emissions from the coke mills, and the range of smaller heaters across a site. The Roadmap also identifies a range of concerns regarding the competitive position of the European steel industry.
It is clear that deep cuts in emissions from iron and steel will require CCS. Additional RD&D and targeted funding will be required to develop CCS technologies for the iron and steel sector and to decrease emissions from steel production. This is consistent with the advice provided by the IEA to the Clean Energy Ministerial earlier this year.