Much of the discussion around energy efficiency tends to center on replacing inefficient devices with newer, more efficient components. Look no further than the humble light bulb, which is now on its third iteration (LEDs, before which came compact fluorescents and the now almost archaic incandescent bulb).

This is perfectly logical, but when it comes to industrial settings, the process itself is just as important as the components used in it, often more so.

Take steel, for example. The industry represents 25 percent of global industrial energy use, not to mention 15 percent of all industrial CO2 emissions (this from ABB’s forthcoming Energy Efficiency Trends report). It is, in fact, the largest single industrial consumer of energy, but the vast majority of it is used not in making steel per se but in making the iron precursor.

Ongoing research

Alternatives to the two main production routes include direct-reduced iron technology and smelting reduction (which, like the blast furnace, produces hot metal). The advantage of these technologies compared with the integrated route is that the raw materials do not need to be treated (‘beneficiated’), e.g. by sintering and making coke, and that they can adjust well to low-grade raw materials. On the other hand, more primary fuels are needed, especially natural gas for direct reduced iron technology and coal for smelting reduction.

20-25% savings in CO2 emissions in the smelting reduction process can be achieved if the additional coal is transformed into process gases, which are then captured and used to produce heat and electricity. At present in EU-28, only one plant uses direct-reduced iron technology (in Germany), while none of the eight operational facilities for smelting reduction in the world are in Europe.

Technology objective and actions

There is potential for reducing direct CO2 emissions by about 27 Mt per year by applying best practice, including the retro-fitting of existing equipment. This potential however relies strongly on a substitution of local raw materials with increased imports of best performance raw materials from outside the EU (especially ores and coal). 

The industry’s flagship ULCOS programme (Ultra–Low Carbon Dioxide (CO2) Steelmaking), supported by the European Commission and involving a consortium of 48 leading players in industry and research, aims to reduce the CO2 emissions of today’s best routes by at least 50%. The first phase of ULCOS had a budget of EUR 75 million.

As a result of the first phase of ULCOS, four main processes have been earmarked for further development. The top gas recycling blast furnace is based on the separation of the off-gases so that the useful components can be recycled back into the furnace and used as a reducing agent. Meanwhile, oxygen is injected into the furnace instead of preheated air to facilitate CO2 capture and storage (CCS). The timeline to complete the demonstration programme is about 10 years, allowing further market roll-out after 2020.

The HIsarna technology combines preheating of coal and partial pyrolysis in a reactor, a melting cyclone for ore melting and a smelter vessel for final ore reduction and iron production. Market roll-out is scheduled for 2030. The ULCORED (advanced Direct Reduction with CCS) involves the direct reduction of iron ore by a reducing gas produced from natural gas. The reduced iron is in a solid state and will need an electric arc furnace to melt the iron. An experimental pilot plant is planned in Sweden, with market roll-out foreseen for 2030. The experimental processes, known as ULCOWIN and ULCOSYS, are electrolysis processes to be tested on a laboratory scale.

In thermal power plants, the development of new steel grades will increase temperature and pressure and will contribute to the improvement of energy efficiency. In advanced supercritical plants with steam conditions up to 600°C and 30 MPa, net efficiencies between 46 and 49% could be reached whereas older pulverised coal plants, with subcritical steam parameters, operate with efficiencies between 32 - 40%. Each percentage point efficiency increase is equivalent to a 2.5% reduction in tonnes of CO2 emitted.

The development of new grades (lightweight alloys) for the automotive industry can decrease steel consumption (energy consumption) and at the same time improve the efficiency of the final products – lighter cars will be more efficient.

The industry

The production of crude steel in the EU in 2012 represented about 11% of total world production (1 510 Mt of crude steel), compared to a 24.6% share in 1998. The contraction of the EU’s share in overall world production is largely due to the fact that Chinese production has grown more than fourfold over this period.

The growth of iron and steel production in the EU is estimated at about 1.18% per year up to 2030. The increase in the production would be covered mainly by an increase in the recycling route. Production from the integrated route is expected to stay around its current values.

Barriers

Further increases in the recycling rate beyond the 60% in 2030 will be hampered by the availability of scrap. Such high recycling rates will increase the impurities and reduce overall steel quality. Recycling is associated with high emissions of heavy metals and organic pollutants due to the impurities of scrap.

Meanwhile, the thermochemical efficiency of current blast furnaces is almost optimal. As CO2 emissions are linked to the chemical reaction for the reduction of iron ore, there can be no significant decrease in CO2 emissions without the development of breakthrough technologies, as proposed by ULCOS.

The industry is also facing a social challenge due to the increasing average age of its workforce: more that 20% will retire by 2015 and close to 30% during the following 10 years. The industry will therefore need to attract, educate and secure more qualified people.

Needs

There is a clear need to support the ULCOS research effort with a high share of public funds and to encourage the deployment of these breakthrough technologies.

One important synergy in the quest to curb prospective CO2 emissions through the ULCOS project is by sharing innovation initiatives within the power sector or with other (energy-intensive) manufacturing industries that could launch CCS initiatives (e.g. the cement industry).

Not all the European operators are performing as well as they could, so there is still potential to save energy by bringing them up to the level of the best performers.

Energy use in steelmaking could be reduced by 40 percent, or around 250 Mtoe, if the main producing countries were to have the same energy efficiency as that achieved by the world’s best performer through its current mix of processes. However, that might be a tall order. Replacing components like motors with more efficient units will certainly yield results, but any major advance in the efficiency of steelmaking will need to address the iron making process itself.

Electric arc furnaces (EAF) are more efficient than blast furnaces, but the EAF process is used mainly to melt down scrap metal rather than to fabricate from scratch. This recycling process is so effective, in fact, that according to a report from Climatevision, the industry has now reached a point where the supply of scrap is almost fully accounted for.

Anh Tuan