Abstract

CO is a primary component of basic oxygen furnace gas (BOFG) and can be used for producing fuel and various value-added chemicals. It can be typically obtained from steel mill gases via separation. Herein, suitable bed operation configurations for vacuum pressure swing adsorption (VPSA) were determined based on the desired CO product purity (PUR_CO,P) when separating CO from simulated BOFG (CO:CO₂:N₂:CH₄ = 65:20:10:5 mol%) using a numerical model validated with experimental data. By changing the operation steps, one case of two-bed, four-step (2-bed), one case of three-bed, five-step (3-bed), and two cases of four-bed, six-step (4-bed_base and 4-bed_mod) operation configurations were considered at a setting temperature of 60 ℃, desorption pressure of 0.13 kgf cm⁻², and adsorption pressure in the range of 2.5–4.0 kg_f cm⁻². The sensitivities of these four operation configurations were evaluated to compare the separation performance and economic benefits of each operation configuration. In the 2-bed case, the PURCO,P demonstrates a separation limit (92.1–92.7 mol%). When targeting PUR_CO,P ≥ 99.00 mol%, the 3-bed case presents the most favorable CO recovery values (REC_CO,P; 92.97–94.13 %) and unit production costs of CO (UPC_CO; 0.252–0.357 US$ Nm⁻³), whereas the 4-bed_mod case presents optimal REC_CO,P (82.06–91.65 %) and UPC_CO values (0.273–0.406 US$ Nm⁻³) when targeting PUR_CO,P ≥ 99.99 mol%, under the same operating conditions. These results indicate cost-effective CO-VPSA process configurations for enriching CO from BOFG, based on the target PUR_CO,P.