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

Abstract

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.

Correlating Impacts of Injected Fuels on Carbon Emissions in Blast Furnace with Computational Fluid Dynamics Modeling

“…As mentioned in Section 2.2, the simulations with syngas injection assumed the same wind rate, O 2 enrichment, and hot blast temperature of the baseline case (see Table 4). More details of this set of computational simulations are presented in the study by Nielson et al [ 11 ]…”

“…The original scenarios were simulated using a BF CFD platform, with results investigating feasibility of injected fuels and stability of furnace operation presented in previous works. [ 9,11,16 ]…”

“…The compositions of the three syngas types are listed in Table 6 . Furnace performance under scenarios holding to this scheme was studied in a previous investigation by Nielson et al [ 11 ] The third scheme utilizes H 2 and blends of H 2 /NG injected at the tuyere, at multiple injection rates. These cases were presented in a recent work by Okosun et al [ 16 ]…”

“…Computational studies have demonstrated that syngas injection can be utilized with stable raceway flame temperatures when injected at similar rates as NG, and it is possible to inject syngas at temperatures as high as 700 °C without adversely affecting BF operation or wear. [ 11 ] An investigation performed using the Aspen model showed the impact of syngas injection on the BF performance and CO 2 emissions. [ 12 ] Specifically, the study considered syngas from CO 2 electrolysis, syngas from biomass gasification, syngas from reverse water–gas shift (RWGS) reaction, and syngas from waste plastic gasification.…”

Multi-Step Recycling of BF Slag Heat via Biomass for CO2 Mitigation

“…1 Value estimation based on [18,28] with exemplary injection rates of 100 m 3 /t HM . 2 Value calculated by assuming coke's CO 2 footprint described in Table 1.…”