Green ironmaking: Multiscale model to study hydrogen injection in a shaft furnace (DRI) and hydrogen injection with coal in the blast furnace with validation
Indian Institute Of Science, Cv Raman Road,Karnataka,Bengaluru Urban-560012
Project Overview
India is committed to net zero carbon emission by 2070. Many researchers worldwide are working to reduce carbon foot print in various areas. Iron and steel making contributes about 7% of total carbon emission. Therefore, it is very important that one must reduce carbon foot print in this sector. 70% carbon emission comes from iron making operation/production which is still dominated by the blast furnace (BF) [1]. Reduction in emissions are difficult to adapt decarbonisation technology due to heavily using fossil fuel. As reported, 1.9 tonnes of CO2 (tCO2) are emitted per tonne of steel production [2], and most of the emission is caused by ironmaking due to intensive consumption of coke and coal in comparison to steelmaking by the basic oxygen furnace or electric arc furnace. Thus, decarbonisation challenge for iron and steel industry is how to maximise the usage of hydrogen which is a zero-carbon resource to replace coke and coal. It is unlikely that at least couple of decades BF technology will be challenged/replaced by any new technology at commercial scale. Therefore, to reduce the carbon footprint one must use alternative fuel to reduce the iron ore than the carbon. As green hydrogen (GH2) production may increase in 2-3 decades commercially, therefore, it is possible to use GH2 as reductant in the blast furnace to reduce the carbon consumption and use it for Direct Reduced Iron (DRI) production (without using any carbon-source) for iron production. GH2 ironmaking is a challenged due to its endothermic nature of reaction, between the iron oxide/s and hydrogen, which will require external heat source for sustaining the process. Kinetics of iron oxide/s reduction by hydrogen plays an important role as it is highly dependent on temperature. Therefore, heat and mass transfer study becomes very crucial for the success of the process and to propose a possible solution for the feasibility of the operations. In order to study these processes, a multiscale heat and mass transfer model along with CFD model is proposed with the experiments for verification. Due to the different properties of H2 and nature of the moving bed in the furnace, the effect of field variables (like bed permeability, gas velocity etc) would be significant on the whole process which will be studied in details. Validation of the model/s against laboratory scale model and plant data is also envisaged. JSW Steel has agreed to provide all the plant data for verification of the model.