Tuyere-Level Syngas Injection in the Blast Furnace: A Computational Fluid Dynamics Investigation

With the recent push towards high injection rate blast furnace operation for economic and environmental reasons, it has become desirable in North America to better understand the impacts of alternate injected gas fuels in comparison to the well-documented limitations of natural gas. The quenching effects of gas injection on the furnace present a functional limit on the maximum stable injection rate which can be utilized. With this in mind, researchers at Purdue University Northwest's Center for Innovation through Visualization and Simulation utilized previously developed computational fluid dynamics (CFD) models of the blast furnace to explore the impacts of replacing natural gas with syngas in a blast furnace with a single auxiliary fuel supply. Simulations predicted that the syngas injection can indeed reduce coke consumption in the blast furnace at similar injection rates to natural gas while maintaining stable raceway flame and reducing gas temperatures. The coke rates predicted by modeling using similar injection rates indicated an improvement of 8 to 15 kg/thm compared to baseline conditions when using the syngas of various feedstocks. Additionally, syngas injection scenarios typically produced higher raceway flame temperatures than comparable natural gas injection cases, indicating potential headroom for reducing oxygen enrichment in the hot blast or providing an even higher total injection rate.