The grand challenge to be addressed is the decarbonisation of Höganäs activities. Specifically, for recycling heat and CO2, the main challenges are:
These innovations do not require new technology to be developed. Rather, it is a question of new applications of technology and of system optimization.
The need to use low-grade heat arises from the previous sale of all higher-grade heat to district heat. To achieve the required capacity, the heat recycling must be designed for a 50-55°C supply and 25°C return. This can be achieved by adding ventilation heat to the standard radiative heat, or by simply adding more area for radiative heat.
To use the CO2 from the sponge iron plant, harmful substances must be removed, notably NOx (harmful to plants) and CO (harmful to humans). Air and water vapor hinder pressurized storage for daily balancing; water vapor may condense in pipes causing blockage.
So, both must be removed. Two suppliers of separation technology have offered systems for separation, one based on absorption-desorption and one membrane-based. For the project, the main modification is the integration into the heat recycling system, to lessen costs and environmental impacts.