This study used the Eulerian approach to investigate the effect of the type of gas on the depth of penetration and bubble distribution in a 2.5 × 0.3 × 5 m slag-fuming furnace without considering chemical reactions. The research compared the depth of penetration of air and hydrogen under similar injection conditions, specifically with a nozzle velocity (Vn) ranging from 10 to 110m/s and a temperature of 400 K, through a tuyere nozzle with a diameter (Dn) of 50 mm. The slag, a multicomponent liquid consisting of 12 components, is kept at a constant temperature (Ts) of 1,220 K. The gas-liquid interaction is simulated fortwo seconds using Star CCM+, employing the k -ϵ turbulence model and the S-Gamma model for the population model. Adaptive mesh refinement and adaptive time steps are utilised to accurately capture the liquid-gas interface and ensure convergence control. In the present study, while airflow carries coal particles, hydrogen flows as pure gas (without coal particles) through the nozzles (tuyere). Following thorough validation against experimental and numerical data, the study compared the Froude number for hydrogen and air in the specified range of Vn. The results indicate that the bubbles are concentrated within a range of 4.3 to 8.1 mm in front of the nozzle. Over time, the distribution of bubble sizes in the upward-moving zone expands. This expansion is likely due to the merging of bubbles, the increasing penetration depth, and the swelling velocity of the slag.