Numerical Investigation of Burden Distribution in Hydrogen Blast Furnace

Hydrogen injection is a promising technology currently under development to reduce CO2 emissions in ironmaking blast furnaces (BFs). Therefore, hydrogen BF is studied by a recent process model based on computational fluid dynamics (CFD). It focuses on the effect of peripheral opening extent (POE), which represents the coke amount near the furnace wall. The simulations consider a 380 m(3) BF operated with hydrogen injection through both shaft and hearth tuyeres. The overall performance of the BF is analyzed in terms of the inner states. It shows that increasing POE hinders the pre-reduction and pre-heating roles of shaft-injected hydrogen (SIH) but improves the CO indirect reduction rate. An optimum peripheral opening extent can be identified to achieve a maximum hot metal (HM) temperature, relatively low bed pressure, and good gas utilization. The interaction between SIH flow rate and burden distribution is also quantified. It shows that the increase in SIH flow rate slows down the CO indirect reduction rate but enhances the H-2 indirect reduction rate. These opposite trends account for the less variation of HM temperature with POE as the SIH flow rate increases. This variation becomes trivial at relatively large SIH flow rates and small POEs. Overall, the POE affects the cohesive zones more than the SIH flow rate. However, under the conditions considered, both variables cannot significantly improve the penetration of the shaft injection, the effect of which is generally confined within the peripheral region.

Automated summary

The study examines the effects of peripheral opening extent and shaft-injected hydrogen flow rate on the performance of a hydrogen blast furnace using computational fluid dynamics. Increasing the peripheral opening extent hinders the pre-reduction and pre-heating roles of shaft-injected hydrogen, but improves the CO indirect reduction rate. Increasing the shaft-injected hydrogen flow rate slows down the CO indirect reduction rate but enhances the H-2 indirect reduction rate.