The metallurgical properties and the microstructure of coke after gasification reaction with pure H₂O and pure CO₂ were investigated in this study. Moreover, the first-principles calculation was conducted to study the reaction process of the carbon with pure H₂O and pure CO₂. The results show that the CRI (coke reaction index) increases sharply and the CSR (coke strength after reaction) decreases sharply, when the cokes are gasified with H₂O as compared to CO₂. The scanning electronic microscopy images and the coke panoramagrams show that H₂O more easily leads to the generation of large pores (>500 μm) and destroys the coke structure than CO₂. The X-ray diffraction results indicate that the arrangement of carbon atoms of coke becomes regular and the ordered degree of coke increases after reaction with CO₂ and H₂O; however, after being gasified with H₂O, the cokes have a higher ordered degree than with CO₂. The results of the first-principles calculation show that the H₂O molecule is more likely to react with carbon as compared to the CO₂ molecule due to the lower energy barriers of H₂O adsorption and H₂ formation. The M2 → FS reaction process is the controlled step of the C-H₂O reaction process, as well as in the C-CO₂ reaction system.

中文翻译：

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H ₂ O / CO ₂气氛下冶金焦的气化反应性和结构演变

研究了纯H ₂ O和纯CO ₂气化反应后焦炭的冶金性能和显微组织。此外，进行了第一性原理计算，以研究碳与纯H ₂ O和纯CO ₂的反应过程。结果表明，与CO ₂相比，H ₂ O气化焦炭时，CRI（焦炭反应指数）急剧上升，CSR（反应后焦炭强度）急剧下降。扫描电子显微镜图像和焦炭全景图显示，与CO ₂相比，H ₂ O更容易导致大孔（> 500μm）的产生并破坏焦炭结构。X射线衍射结果表明，与CO ₂和H ₂ O反应后，焦炭的碳原子排列变得规则，焦炭的有序度增加。然而，在用H ₂ O气化后，焦炭的有序度比用CO _2高。第一性原理的计算结果表明，由于H ₂ O吸附和H ₂形成的能垒较低，因此与CO ₂分子相比，H ₂ O分子更可能与碳发生反应。M2→FS反应过程是CH ₂ O反应过程的受控步骤，也是C-CO ₂ 反应系统。