Currently, Tata Steel IJmuiden is developing a new ironmaking process, called HIsarna. This technique will result in a significant reduction of carbon emissions, allow for more flexible input requirements for materials, and lead to a reduction of processing costs as well. In 2010, Tata Steel IJmuiden built a pilot plant to test and develop the technology of HIsarna. The next step is an industrial scale installation: the HIsarna demonstration plant. The design of the storage and handling area of this new plant is the subject of this research. At this area, the materials are stored and pre-processed before they will be injected into HIsarna.
Thus far, Tata Steel has been working on the first design phase of the demonstration plant. Nevertheless, the design of the storage and handling area is missing. Consequently, the required quantities and necessary pre-processing steps of materials are unknown. Moreover, the existing storage and handling area at the HIsarna pilot plant cannot directly be used for the demonstration plant, because the new plant must meet HIsarna’s annual capacity requirements of around one million mt, be able to process iron-rich waste materials (also called reverts), and comply with HIsarna’s green ambitions.
First, an analysis of materials is performed to establish the suitable materials and their properties for processing at the HIsarna demonstration plant. This analysis is essential to identify how these properties may affect the design of the storage and handling area. Second, the storage and handling area of the HIsarna pilot plant is analysed, particularly to identify the necessary processing steps and potential future bottlenecks of the HIsarna demonstration plant. Next, a design of the storage and handling area is created by using multi-criteria analyses and information obtained from literature. A simulation model, created in Simio® software and verified using several techniques, is used to examine the performance of the design, but also to investigate the affecting parameters; these are found by performing a fractional factorial design. Based on these results, optimal parameter settings are found to optimise the design.
According to analyses performed, the suitable materials for HIsarna (besides the standard materials such as iron ore and coal) are by-products of the blast furnaces and the oxy steel plant: BF sludge, currently produced BOF sludge and historic BOF sludge. These materials are particularly interesting because of the high levels of iron, carbon and zinc. Less positive are the high moisture level, the stickiness and the inhomogeneity of composition. These might result in problems during processing. The following design is created: iron ore and coal will be transported by conveyor belt to the storage and handling area, historic BOF sludge by truck, and BF and currently produced BOF sludge by pipeline. Both the raw and handled materials will be stored in enclosed storage systems. Each material will be pre-processed at a dedicated handling line; all materials within the storage and handling area are transported by conveyor belt. The raw material storage of iron ore, coal and BOF sludge has a capacity for two days; and that of BF and currently produced BOF sludge for seven days. In addition, all handled material storages have a capacity of three days.
Based on the results of the fractional factorial design, three designs for the storage and handling area are proposed. Each of the designs has a different starting point. The second design option provides the highest reliability and is recommended if financial resources are not a restrictive factor. The third design is an interesting choice when fewer financial resources are available but still an adequate reliability is aimed at. Finally, the first design results in the lowest reliability. This option may only be suggested when funds are limited. In all cases, redundancy can be added to the storage and handling area, increasing the reliability and decreasing the required storage capacity. All designs fit the selected location at the Tata Steel site, IJmuiden.