Study on the Gasification Reaction and Structure Evolution of Metallurgical Coke Under CO ₂ –CO–N ₂ /H ₂ –CO ₂ –CO–N ₂

This study investigated the gasification behavior and structural evolution of metallurgical coke under CO–CO 2 –N 2 /H 2 –CO–CO 2 –N 2 gas mixtures from both macroscopic and microscopic perspectives. The introduction of H 2 into a CO–CO 2 –N 2 mixture significantly enhanced the conversion rates of both tamping coke and top‐charging coke as the CO 2 content increased from 10% to 30%. Specifically, the conversion rates improved by 1.5‐, 1.7‐, and 2.1‐fold for tamping coke, and by 1.3‐, 1.4‐, and 1.5‐fold for top‐charging coke, compared with reactions conducted without H 2 . In contrast, the strength after reaction of coke decreased with increasing CO 2 content in the H 2 –CO–CO 2 –N 2 mixture. Notably, H 2 reacted with CO 2 to generate H 2 O, which in turn promoted the gasification of coke. Comparative analyses of optical texture index, pore structure, micromorphology, elastic modulus, and hardness indicated that gasification in CO–CO 2 –N 2 /H 2 –CO–CO 2 –N 2 mixtures decreased the anisotropic texture, elastic modulus, and hardness of coke, while simultaneously increasing its specific surface area, pore volume, and average pore size. Moreover, under identical reaction conditions, tamping coke exhibited a higher susceptibility to gasification than top‐charging coke. These findings suggest that H 2 promotes coke gasification through its reaction with CO 2 to produce H 2 O, leading to reduced anisotropic structure, enlarged pores, increased surface area, and diminished microstrength.