PRELIMINARY EVALUATION OF RETROFITTING AN ALUMINA FLASH CALCINER FROM NATURAL GAS TO HYDROGEN

This study presents a preliminary evaluation of the retrofit of a 60MW alumina flash calciner from natural gas to hydrogen fuel. Through the utilisation a combination of zero-dimensional (0-D) theoretical analysis and Computational Fluid Dynamics (CFD) simulations, we assess the operational impacts of this transition on the calciner’s performance. Preliminary 0-D model assessments are conducted to estimate both flame and outlet temperatures, while also predicting potential operational adjustments. These assessments inform the selection of input parameters for subsequent CFD simulations. Subsequently, CFD analyses are conducted to provide detailed insights into thermal and flow characteristics under single-phase conditions, evaluating the temperature and velocity distribution along with flue gas composition within the calciner. Transitioning to hydrogen leads to a decrease in outlet temperature due to the higher specific heat capacity and concentration of steam produced in the flue gases, requiring cautious operational adjustments to maintain similar outlet boundary conditions while ensuring downstream equipment performance is maintained.