An important task in the structure of the ULCOS program has been to provide a fair and homogeneous comparison among the elements of the initial and the short lists of processes, which are candidates to become the ultimate ULCOS, carbon-lean breakthrough steel production processes of the future. Eventually, that information is being used to provide the rationale for moving forward in the selection of the future best technologies. The CO2 tool, developed within SP9, the subproject devoted to measuring the sustainability of the proposed ULCOS processes, is one of the key tools worked out but also used to carry out this essential part of the ULCOS program.
The CO2 tool is a mass and energy balance model of a complete steel mill, i.e. a steel mill simulator, which focuses on estimating energy consumption and GHG emissions of a hot mill site. It applies a standard analysis to all the process routes proposed in the course of the ULCOS program, by normalizing the size of the site (4 Mt/y), the nature of the raw materials it uses, the scrap input in the steel shop and a number of other parameters. The tool is fed by process data of the various plants lined up in the steel mil, which have been generated by more detailed models and also arise from experimental data, when they are available. The tool is meant to feed a further tool that compares the production and Abstracts of technical articles investment costs in various scenarios extending until 2050, with a series of mild to strong carbon constraints.
The structure of the tool as well as the results it brought about are presented here. The major conclusion is that several solutions offer the possibility to cut steel mill emission by more than 50% compared to the baseline “best technology” steel mill, provided that breakthrough solutions are taken into account, based on the uncoupling of energy savings and CO2 mitigation targets.