A numerical study on process intensification of hydrogen reduction of iron oxide pellets in a shaft furnace

•Process intensification of the H2 shaft furnace is investigated using a simplified algebraic model and a CFD shaft furnace model.•The theoretical maximum gas utilization degree is determined.•Process intensification can be achieved with a higher pellet reducibility or operating pressure.•Extending the reduction zone lowers the productivity of the H2 shaft furnace.•Optimal operating parameters for the H2 shaft furnace are determined.