Monitoring of blast furnace wall pressure profiles and their relation to process efficiency

The blast furnace process for ironmaking is highly optimised and very energy efficient. However, due to its dependency on coke, not only as an energy carrier but also as a chemical reductant and provider of gas permeability, it is responsible for high CO 2 emissions. Consequently, steel producers search for operation modes to minimise emissions, e.g., such as increasing the share of hydrogen-based reduction. For such new operational set points, operators have less experience in how to maintain a stable and most efficient process state. At Hüttenwerke Krupp Mannesmann, experience has shown that especially in the shaft region of the blast furnace most process instabilities arise from non-optimal gas permeability of the burden column and non-uniform burden descend. Such process disturbances can be recognised at a very early stage through careful monitoring of the gas pressures along the shaft wall. A study has been performed how different process gas pressure profiles, measured vertically alongst the blast furnaces wall, can indicate different process states with different efficiencies. A monitoring tool to automatically supervise the profile shape and indicate warning to blast furnace operators in case of non-optimal profiles has been developed. Data analysis has been performed to demonstrate the relevance of the findings. The results show that a better process efficiency, meaning lower CO 2 emissions, can be achieved by careful monitoring of the blast furnace wall pressures.