At the Unit of Processes, one of our main areas of focus in recent years has been the improvement of cleanliness in steels. That means removing contaminants and preventing the production of unwanted particles in the steel during processing. This will improve capabilities of steel and reduce wastage, both of which provide a direct contribution to sustainable development.
Background
It is well known that industrial processes are very energy- and materials intensive. As such, they contribute significantly to global greenhouse gas emissions. During the last two decades, the following studies have been carried out to study how environmental and economical improvements may be achieved:
- laboratory experiments:
- For the treatment of waste from electronic products
- production of oil from paper by-products
- neutralization of acidic waste from steelmaking using other basic waste products
- modeling
- computational fluid dynamics of steelmaking processes
- quantum simulations
- chemical, thermodynamic and mass transport simulations
- plant trials
- recycling of slags
- neutralization of acidic waste from steelmaking using other basic waste products
- steel scrap utilization
Current research with a focus on carbon mitigation include the following areas:
- carbon-free steelmaking (HYBRIT, IRONARC)
- new heating technologies for industrial furnaces (electrical, plasma)
- replacement of fossil fuel with renewable energy (biomass thermal conversion for syngas, biooil)
- replacement of fossil reducing agents such as coke and coal with local available biomass and waste (bio coke).
Current research with a focus on circular economy include the following areas
- recycling materials and energy from society/municipal solid waste (New-Mine landfill mining, recycling energy and metals from WEEE- waste electrical and electronics)
- recycling of waste stream from other process industries such as paper and pulp into steelmaking
- utilization of steel waste streams, in particular slags, for waste water treatment
- modeling of canister materials for spent nuclear fuel disposal.
Since 2012, this new knowledge has been shared to industry and the community through 101 articles in scientific journals, four book chapters, 15 doctoral theses, two licentiate theses and several life-long learning seminars. These efforts have led to the J. Rydberg award from CTH for best PhD thesis in the field of recirculation and circular economy (A. Gauffin – MFA) and the American Society of Mechanical Engineers (ASME) George Westinghouse Silver Medal for W. Yang in 2012.
Unique developments at the Unit of Processes in the near future include:
- development of carbon-free steelmaking processes (HYBRIT, IRONARC)
- the use of metal-making slags for CO2 storage
The ultimate goal of our current activities in this area is to create a center for sustainable process development, waste management and waste utilization with a focus on high-temperature industries, in collaboration with industrial and academic partners in Europe.
Case study - nuclear fuel storage material
The Swedish final repository for spent nuclear fuel is an important national project. Its success will have a large impact in the sustainability and environmental footprint of the nuclear energy in the country. It is now accepted that the long-term sustainability of nuclear power is of high strategic relevance for radically decreasing the usage of fossil fuels and the emissions of greenhouse gases. The Swedish concept for the final repository of spent nuclear fuel, being developed by SKB, has been imported by other countries that see Sweden as a role model in this field. A repository for spent nuclear fuel must maintain its integrity during the whole storage period, to provide safe barriers for containing the radioactive material. The safety assessment has to be done based on integrated scientific knowledge that combines empirical data and theoretical models obtained from experiments, field observations, natural explorations, fundamental theories, and computational modelling.
Initial experiments showed that water could be a threat to the integrity of the canister that contains the spent nuclear fuel. Work performed at the Unit of Processes, in collaboration with SKB, was part of a large-scale investigation on the interactions between water and the surface of the canister, as well as on the effect of impurities and alloying elements on the mechanical properties of canister materials. Our results, together with a series of long-term experiments, show that water alone is not able to drive the corrosion of the canister nor to affect the integrity of the canister material. These results had a large impact on the decision to develop the long-term storage concept for spent nuclear fuel in Sweden. The existence of such a solution has many societal and environmental benefits. The primary benefits are the containment of radiation and its non-proliferation to the biosphere with important implications for people and nature. The medium-term benefits are related with the existence of a reliable and constant energy supply that nuclear reactors can provide. The long-term benefits are related with the transition from fossil fuel to sustainable sources of energy.
The knowledge obtained in these research studies during the last eight years has been shared to the industry and society through 38 peer reviewed publications in scientific journals, one book chapter, eight open-access technical reports, four doctoral theses, one licentiate thesis and presentations at numerous industrial and scientific meetings. The scientific methodology that was developed will be useful in future studies of:
- the effects of hydrogen in the properties of metals
- the development of structural and functional materials for non-fossil fuel based energy technology